/*
================================================================================
HSK LEARNING APP - MODERN DESIGN SYSTEM
================================================================================

Version: 2.1.0
Author: Jose Alejandro Rollano Revollo
Description: Advanced Chinese learning platform with modern UX/UI
Last Updated: 2025

Table of Contents:
1. Design System Variables
2. Reset & Base Styles
3. Typography System
4. Layout & Container System
5. Component Styles
   - Header & Navigation
   - Flashcards
   - Buttons & Forms
   - Statistics & Progress
   - Quiz Interface
   - Vocabulary Browser
6. Theme System (Dark Mode)
7. Micro-interactions & Animations
8. Utility Classes
9. Responsive Design
10. Accessibility & Performance

================================================================================
*/

/* ============================================================================
   1. DESIGN SYSTEM VARIABLES
   ============================================================================ */

:root {
    /* 
    Color System
    --------------------------------------------------------------------------
    A comprehensive color palette with semantic naming and consistent scales.
    Each color has variants from 50 (lightest) to 900 (darkest).
    */
    
    /* Primary Colors - Rose/Pink theme for brand identity */
    --color-primary: #e11d48;
    --color-primary-50: #fdf2f8;
    --color-primary-100: #fce7f3;
    --color-primary-200: #fbcfe8;
    --color-primary-300: #f9a8d4;
    --color-primary-400: #f472b6;
    --color-primary-500: #e11d48;
    --color-primary-600: #be123c;
    --color-primary-700: #9f1239;
    --color-primary-800: #881337;
    --color-primary-900: #4c0519;
    
    /* Secondary Colors - Slate theme for neutral elements */
    --color-secondary: #0f172a;
    --color-secondary-50: #f8fafc;
    --color-secondary-100: #f1f5f9;
    --color-secondary-200: #e2e8f0;
    --color-secondary-300: #cbd5e1;
    --color-secondary-400: #94a3b8;
    --color-secondary-500: #64748b;
    --color-secondary-600: #475569;
    --color-secondary-700: #334155;
    --color-secondary-800: #1e293b;
    --color-secondary-900: #0f172a;
    
    /* Accent Colors - Amber theme for highlights and CTAs */
    --color-accent: #f59e0b;
    --color-accent-50: #fffbeb;
    --color-accent-100: #fef3c7;
    --color-accent-200: #fde68a;
    --color-accent-300: #fcd34d;
    --color-accent-400: #fbbf24;
    --color-accent-500: #f59e0b;
    --color-accent-600: #d97706;
    --color-accent-700: #b45309;
    --color-accent-800: #92400e;
    --color-accent-900: #78350f;
    
    /* Semantic Colors - For status and feedback */
    --color-success: #10b981;
    --color-success-50: #ecfdf5;
    --color-success-100: #d1fae5;
    --color-success-200: #a7f3d0;
    --color-success-300: #6ee7b7;
    --color-success-400: #34d399;
    --color-success-500: #10b981;
    --color-success-600: #059669;
    --color-success-700: #047857;
    --color-success-800: #065f46;
    --color-success-900: #064e3b;
    
    --color-warning: #f59e0b;
    --color-warning-50: #fffbeb;
    --color-warning-100: #fef3c7;
    --color-warning-200: #fde68a;
    --color-warning-300: #fcd34d;
    --color-warning-400: #fbbf24;
    --color-warning-500: #f59e0b;
    --color-warning-600: #d97706;
    --color-warning-700: #b45309;
    --color-warning-800: #92400e;
    --color-warning-900: #78350f;
    
    --color-error: #ef4444;
    --color-error-50: #fef2f2;
    --color-error-100: #fee2e2;
    --color-error-200: #fecaca;
    --color-error-300: #fca5a5;
    --color-error-400: #f87171;
    --color-error-500: #ef4444;
    --color-error-600: #dc2626;
    --color-error-700: #b91c1c;
    --color-error-800: #991b1b;
    --color-error-900: #7f1d1d;
    
    /* 
    Theme Colors - Light Mode
    --------------------------------------------------------------------------
    Semantic color assignments for different UI elements in light theme.
    */
    --bg-primary: #fefefe;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #94a3b8;
    
    --border-color: #e2e8f0;
    
    /* 
    Typography System
    --------------------------------------------------------------------------
    Responsive typography scale using clamp() for fluid scaling.
    Font families optimized for Chinese character display.
    */
    --font-primary: 'JetBrains Mono', 'Noto Sans SC', monospace;
    --font-chinese: 'JetBrains Mono', 'Noto Sans SC', monospace;
    
    /* Responsive font sizes - automatically scale with viewport */
    --font-size-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
    --font-size-sm: clamp(0.875rem, 0.8rem + 0.375vw, 1rem);
    --font-size-base: clamp(1rem, 0.9rem + 0.5vw, 1.125rem);
    --font-size-lg: clamp(1.125rem, 1rem + 0.625vw, 1.25rem);
    --font-size-xl: clamp(1.25rem, 1.1rem + 0.75vw, 1.5rem);
    --font-size-2xl: clamp(1.5rem, 1.3rem + 1vw, 2rem);
    --font-size-3xl: clamp(2rem, 1.7rem + 1.5vw, 3rem);
    --font-size-4xl: clamp(3rem, 2.5rem + 2.5vw, 4rem);
    --font-size-5xl: clamp(3.5rem, 3rem + 3vw, 5rem);
    --font-size-6xl: clamp(4rem, 3.5rem + 3.5vw, 6rem);
    
    /* Line height scale for optimal readability */
    --line-height-tight: 1.1;
    --line-height-snug: 1.2;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.6;
    --line-height-loose: 1.8;
    
    /* Letter spacing for different text styles */
    --letter-spacing-tight: -0.05em;
    --letter-spacing-normal: 0;
    --letter-spacing-wide: 0.025em;
    --letter-spacing-wider: 0.05em;
    --letter-spacing-widest: 0.1em;
    
    /* 
    Spacing System
    --------------------------------------------------------------------------
    Consistent spacing scale using responsive units.
    Based on 8px grid system with fluid scaling.
    */
    --space-px: 1px;
    --space-0: 0;
    --space-xs: clamp(0.25rem, 0.2rem + 0.25vw, 0.375rem);
    --space-sm: clamp(0.5rem, 0.4rem + 0.5vw, 0.75rem);
    --space-md: clamp(1rem, 0.8rem + 1vw, 1.5rem);
    --space-lg: clamp(1.5rem, 1.2rem + 1.5vw, 2.25rem);
    --space-xl: clamp(2rem, 1.6rem + 2vw, 3rem);
    --space-2xl: clamp(3rem, 2.4rem + 3vw, 4.5rem);
    --space-3xl: clamp(4rem, 3.2rem + 4vw, 6rem);
    --space-4xl: clamp(5rem, 4rem + 5vw, 7.5rem);
    
    /* 
    Border Radius System
    --------------------------------------------------------------------------
    Consistent border radius scale for different component sizes.
    */
    --radius-xs: 0.25rem;
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Legacy support */
    --border-radius: var(--radius-lg);
    --border-radius-sm: var(--radius-sm);
    --border-radius-lg: var(--radius-xl);
    
    /* 
    Shadow System
    --------------------------------------------------------------------------
    Layered shadow system for depth and elevation.
    Optimized for both light and dark themes.
    */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 10px 10px -5px rgb(0 0 0 / 0.04);
    --shadow-2xl: 0 25px 50px -12px rgb(0 0 0 / 0.25);
    
    /* 
    Animation System
    --------------------------------------------------------------------------
    Consistent timing functions and durations for smooth animations.
    */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 300ms cubic-bezier(0.68, -0.55, 0.265, 1.55);
    
    /* 
    Layout System
    --------------------------------------------------------------------------
    Container sizes and layout constraints.
    */
    --container-xs: 20rem;
    --container-sm: 24rem;
    --container-md: 28rem;
    --container-lg: 32rem;
    --container-xl: 36rem;
    --container-2xl: 42rem;
    --container-3xl: 48rem;
    --container-4xl: 56rem;
    --container-5xl: 64rem;
    --container-6xl: 72rem;
    --container-7xl: 80rem;
    
    /* 
    Z-Index System
    --------------------------------------------------------------------------
    Consistent layering system for overlapping elements.
    */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
    
    /* 
    Interactive States
    --------------------------------------------------------------------------
    Consistent opacity and focus ring styles.
    */
    --hover-opacity: 0.8;
    --disabled-opacity: 0.5;
    --focus-ring: 0 0 0 3px rgba(225, 29, 72, 0.1);
    --focus-ring-dark: 0 0 0 3px rgba(251, 191, 36, 0.2);
}
/*
 ============================================================================
   2. RESET & BASE STYLES
   ============================================================================ */

/*
Modern CSS Reset
--------------------------------------------------------------------------
Removes browser inconsistencies and provides a clean foundation.
*/
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/*
Base HTML Elements
--------------------------------------------------------------------------
Foundation styles for semantic HTML elements.
*/
html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
    -ms-text-size-adjust: 100%;
}

body {
    font-family: var(--font-primary);
    background: var(--bg-secondary);
    color: var(--text-primary);
    line-height: var(--line-height-relaxed);
    font-size: var(--font-size-base);
    font-weight: 400;
    letter-spacing: var(--letter-spacing-wide);
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    min-height: 100vh;
    position: relative;
    transition: background-color var(--transition-base), color var(--transition-base);
}

/*
Background Effects
--------------------------------------------------------------------------
Subtle background patterns and overlays for visual depth.
*/
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: url('logo_background.png');
    background-repeat: no-repeat;
    background-position: center center;
    background-size: cover;
    opacity: 0.15;
    z-index: -2;
    pointer-events: none;
}

body::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.9) 0%, 
        rgba(249, 250, 251, 0.85) 100%);
    z-index: -1;
    pointer-events: none;
}

/* ============================================================================
   3. TYPOGRAPHY SYSTEM
   ============================================================================ */

/*
Heading Hierarchy
--------------------------------------------------------------------------
Semantic heading styles with consistent spacing and typography.
*/
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-primary);
    font-weight: 700;
    line-height: var(--line-height-tight);
    color: var(--text-primary);
    letter-spacing: var(--letter-spacing-tight);
    margin-bottom: var(--space-md);
    text-wrap: balance;
}

h1 { 
    font-size: var(--font-size-5xl); 
    line-height: var(--line-height-tight);
    margin-bottom: var(--space-lg);
}

h2 { 
    font-size: var(--font-size-4xl); 
    line-height: var(--line-height-tight);
    margin-bottom: var(--space-lg);
}

h3 { 
    font-size: var(--font-size-3xl); 
    line-height: var(--line-height-snug);
    margin-bottom: var(--space-md);
}

h4 { 
    font-size: var(--font-size-2xl); 
    line-height: var(--line-height-snug);
    margin-bottom: var(--space-md);
}

h5 { 
    font-size: var(--font-size-xl); 
    line-height: var(--line-height-normal);
    margin-bottom: var(--space-sm);
}

h6 { 
    font-size: var(--font-size-lg); 
    line-height: var(--line-height-normal);
    margin-bottom: var(--space-sm);
}

/*
Body Text Elements
--------------------------------------------------------------------------
Paragraph and inline text styling.
*/
p {
    font-size: var(--font-size-base);
    line-height: var(--line-height-relaxed);
    margin-bottom: var(--space-md);
    letter-spacing: var(--letter-spacing-normal);
}

small {
    font-size: var(--font-size-sm);
    line-height: var(--line-height-normal);
    letter-spacing: var(--letter-spacing-wide);
}

/*
Typography Utility Classes
--------------------------------------------------------------------------
Utility classes for quick typography adjustments.
*/
.text-xs { font-size: var(--font-size-xs); }
.text-sm { font-size: var(--font-size-sm); }
.text-base { font-size: var(--font-size-base); }
.text-lg { font-size: var(--font-size-lg); }
.text-xl { font-size: var(--font-size-xl); }
.text-2xl { font-size: var(--font-size-2xl); }
.text-3xl { font-size: var(--font-size-3xl); }
.text-4xl { font-size: var(--font-size-4xl); }

.leading-tight { line-height: var(--line-height-tight); }
.leading-snug { line-height: var(--line-height-snug); }
.leading-normal { line-height: var(--line-height-normal); }
.leading-relaxed { line-height: var(--line-height-relaxed); }
.leading-loose { line-height: var(--line-height-loose); }

.tracking-tight { letter-spacing: var(--letter-spacing-tight); }
.tracking-normal { letter-spacing: var(--letter-spacing-normal); }
.tracking-wide { letter-spacing: var(--letter-spacing-wide); }
.tracking-wider { letter-spacing: var(--letter-spacing-wider); }
.tracking-widest { letter-spacing: var(--letter-spacing-widest); }

/*
Chinese Text Utilities
--------------------------------------------------------------------------
Specialized typography for Chinese characters with optimal spacing.
*/
.chinese-text-sm { 
    font-size: var(--font-size-lg);
    font-family: var(--font-chinese);
    letter-spacing: var(--letter-spacing-wider);
}

.chinese-text-base { 
    font-size: var(--font-size-xl);
    font-family: var(--font-chinese);
    letter-spacing: var(--letter-spacing-wider);
}

.chinese-text-lg { 
    font-size: var(--font-size-2xl);
    font-family: var(--font-chinese);
    letter-spacing: var(--letter-spacing-wider);
}

.chinese-text-xl { 
    font-size: var(--font-size-3xl);
    font-family: var(--font-chinese);
    letter-spacing: var(--letter-spacing-wider);
}

.chinese-text-2xl { 
    font-size: var(--font-size-4xl);
    font-family: var(--font-chinese);
    letter-spacing: var(--letter-spacing-wider);
}

/* ============================================================================
   4. LAYOUT & CONTAINER SYSTEM
   ============================================================================ */

/*
Main Container
--------------------------------------------------------------------------
Primary application container with responsive padding.
*/
.app-container {
    max-width: var(--container-6xl);
    margin: 0 auto;
    padding: var(--space-lg);
    width: 100%;
    animation: pageLoad 0.8s ease-out;
}

/*
Container Variants
--------------------------------------------------------------------------
Different container sizes for various content types.
*/
.container-xs { max-width: var(--container-xs); }
.container-sm { max-width: var(--container-sm); }
.container-md { max-width: var(--container-md); }
.container-lg { max-width: var(--container-lg); }
.container-xl { max-width: var(--container-xl); }
.container-2xl { max-width: var(--container-2xl); }
.container-3xl { max-width: var(--container-3xl); }
.container-4xl { max-width: var(--container-4xl); }
.container-5xl { max-width: var(--container-5xl); }
.container-6xl { max-width: var(--container-6xl); }
.container-7xl { max-width: var(--container-7xl); }/*

Spacing Utilities
--------------------------------------------------------------------------
Utility classes for consistent margin, padding, and gap spacing.
*/

/* Margin utilities */
.m-0 { margin: var(--space-0); }
.m-xs { margin: var(--space-xs); }
.m-sm { margin: var(--space-sm); }
.m-md { margin: var(--space-md); }
.m-lg { margin: var(--space-lg); }
.m-xl { margin: var(--space-xl); }
.m-2xl { margin: var(--space-2xl); }

.mt-0 { margin-top: var(--space-0); }
.mt-xs { margin-top: var(--space-xs); }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }

.mb-0 { margin-bottom: var(--space-0); }
.mb-xs { margin-bottom: var(--space-xs); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }

/* Padding utilities */
.p-0 { padding: var(--space-0); }
.p-xs { padding: var(--space-xs); }
.p-sm { padding: var(--space-sm); }
.p-md { padding: var(--space-md); }
.p-lg { padding: var(--space-lg); }
.p-xl { padding: var(--space-xl); }
.p-2xl { padding: var(--space-2xl); }

/* Gap utilities for flexbox and grid */
.gap-0 { gap: var(--space-0); }
.gap-xs { gap: var(--space-xs); }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }
.gap-xl { gap: var(--space-xl); }
.gap-2xl { gap: var(--space-2xl); }

/* ============================================================================
   5. COMPONENT STYLES
   ============================================================================ */

/* 
Header & Navigation Components
============================================================================ */

/*
Application Header
--------------------------------------------------------------------------
Main header with branding and controls.
*/
.app-header {
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.95) 0%, 
        rgba(249, 250, 251, 0.9) 100%);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-2xl);
    padding: var(--space-2xl);
    margin-bottom: var(--space-xl);
    box-shadow: var(--shadow-lg);
    position: relative;
    border: 1px solid rgba(229, 231, 235, 0.5);
    animation: pageLoad 0.8s ease-out 0.1s both;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-xl);
    flex-wrap: wrap;
}

/*
Brand Section
--------------------------------------------------------------------------
Logo and application title styling.
*/
.brand {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
}

.logo {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.brand-text h1 {
    font-size: var(--font-size-2xl);
    background: linear-gradient(135deg, var(--color-primary-500) 0%, var(--color-secondary-500) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.brand-text p {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    margin-top: var(--space-xs);
}

/*
Header Controls
--------------------------------------------------------------------------
Theme toggle, language selector, and other header controls.
*/
.header-controls {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    flex-wrap: wrap;
}

.btn-icon {
    width: 2.75rem;
    height: 2.75rem;
    border: 2px solid var(--border-color);
    background: linear-gradient(145deg, var(--bg-primary), var(--bg-secondary));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-base);
    color: var(--text-primary);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(10px);
}

.btn-icon::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, 
        transparent, 
        rgba(255, 255, 255, 0.1), 
        transparent);
    transform: translateX(-100%);
    transition: transform var(--transition-base);
}

.btn-icon:hover::before {
    transform: translateX(100%);
}

.btn-icon:hover {
    background: linear-gradient(145deg, var(--bg-tertiary), var(--color-primary-50));
    border-color: var(--color-primary-300);
    transform: translateY(-2px) scale(1.05);
    box-shadow: var(--shadow-lg);
    color: var(--color-primary-600);
}

/*
Theme Toggle Animation
--------------------------------------------------------------------------
Smooth transition between light and dark mode icons.
*/
.theme-icon {
    position: absolute;
    transition: all var(--transition-base);
    font-size: 1.2rem;
}

.theme-icon.light-icon {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

.theme-icon.dark-icon {
    opacity: 0;
    transform: rotate(180deg) scale(0.5);
}

/*
Navigation System
--------------------------------------------------------------------------
Tab-based navigation with enhanced visual feedback.
*/
.nav-container {
    background: linear-gradient(145deg, 
        rgba(255, 255, 255, 0.95), 
        rgba(248, 250, 252, 0.9));
    backdrop-filter: blur(20px);
    border: 1px solid rgba(226, 232, 240, 0.6);
    border-radius: var(--radius-2xl);
    padding: var(--space-sm);
    margin-bottom: var(--space-xl);
    box-shadow: var(--shadow-xl);
    position: relative;
    overflow: hidden;
    animation: pageLoad 0.8s ease-out 0.2s both;
}

.nav-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, 
        var(--color-primary-500), 
        var(--color-accent-500), 
        var(--color-success-500));
    background-size: 200% 100%;
    animation: gradientFlow 3s ease infinite;
}

.nav-tabs {
    display: flex;
    gap: var(--space-xs);
    position: relative;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-xl);
    padding: var(--space-xs);
}

.nav-tab {
    flex: 1;
    padding: var(--space-md) var(--space-lg);
    border: none;
    background: transparent;
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
    font-family: var(--font-primary);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-base);
    font-size: var(--font-size-sm);
    position: relative;
    overflow: hidden;
    letter-spacing: var(--letter-spacing-wide);
    text-transform: uppercase;
    min-height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.nav-tab::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.1), 
        rgba(255, 255, 255, 0.05));
    transform: translateX(-100%);
    transition: transform var(--transition-base);
    border-radius: var(--radius-lg);
}

.nav-tab:hover::before {
    transform: translateX(0);
}

.nav-tab:hover {
    color: var(--text-primary);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.nav-tab.active {
    background: linear-gradient(135deg, 
        var(--color-primary-500), 
        var(--color-primary-600));
    color: white;
    box-shadow: 
        var(--shadow-lg),
        0 0 20px rgba(225, 29, 72, 0.3);
    transform: translateY(-2px);
    position: relative;
    z-index: 2;
}

.nav-tab.active::before {
    display: none;
}

.nav-tab.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 50%;
    transform: translateX(-50%);
    width: 60%;
    height: 3px;
    background: linear-gradient(90deg, 
        var(--color-accent-500), 
        var(--color-accent-400));
    border-radius: var(--radius-full);
    box-shadow: 0 2px 8px rgba(245, 158, 11, 0.4);
}

/*
Content Area
--------------------------------------------------------------------------
Main content container with backdrop effects.
*/
.content-area {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(229, 231, 235, 0.5);
    border-radius: var(--radius-2xl);
    padding: var(--space-2xl);
    box-shadow: var(--shadow-lg);
    position: relative;
    animation: pageLoad 0.8s ease-out 0.3s both;
}

/*
Tab Panel System
--------------------------------------------------------------------------
Content panels with smooth transitions.
*/
.tab-panel {
    display: none;
    opacity: 0;
    transform: translateY(20px);
    transition: all var(--transition-base);
}

.tab-panel.active {
    display: block;
    animation: tabPanelReveal 0.6s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

/* Enhanced tab panel transitions */
.tab-panel {
    transition: opacity 0.3s ease, transform 0.3s ease;
    transform: translateY(10px);
}

.tab-panel.active {
    opacity: 1 !important;
    transform: translateY(0) !important;
}

/* Theme transition system */
.theme-transition {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease !important;
}

.theme-transition * {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease !important;
}

.theme-changing {
    pointer-events: none;
}

.theme-changing * {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1) !important;
}

/* Enhanced theme toggle button */
#theme-toggle {
    position: relative;
    overflow: hidden;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

#theme-toggle::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s ease;
}

#theme-toggle:hover::before {
    left: 100%;
}

.theme-icon {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: inline-block;
}

/* Dark theme improvements */
[data-theme="dark"] {
    --current-bg-primary: #0f172a;
    --current-text-primary: #f8fafc;
    --current-border-color: #475569;
}

[data-theme="light"] {
    --current-bg-primary: #ffffff;
    --current-text-primary: #1e293b;
    --current-border-color: #e2e8f0;
}

/* Tab content staggered animation */
.tab-panel.active > * {
    animation: contentStagger 0.8s ease-out forwards;
    opacity: 0;
    transform: translateY(20px);
}

.tab-panel.active > *:nth-child(1) { animation-delay: 0.1s; }
.tab-panel.active > *:nth-child(2) { animation-delay: 0.2s; }
.tab-panel.active > *:nth-child(3) { animation-delay: 0.3s; }
.tab-panel.active > *:nth-child(4) { animation-delay: 0.4s; }

/* Improved tab button transitions */
.nav-tab {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.nav-tab:hover {
    transform: translateY(-2px) scale(1.02);
}

.nav-tab.active {
    transform: translateY(-3px) scale(1.05);
}

/* Loading state for tab buttons */
.nav-tab:disabled {
    pointer-events: none;
    opacity: 0.7;
}

/* Tab switch loading indicator */
.nav-tab.switching::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, 
        transparent, 
        rgba(255, 255, 255, 0.3), 
        transparent);
    animation: tabSwitchLoading 1s ease-in-out infinite;
}

@keyframes tabSwitchLoading {
    0% { left: -100%; }
    100% { left: 100%; }
}/* 
Butt
on System
============================================================================ */

/*
Base Button Styles
--------------------------------------------------------------------------
Foundation styles for all button variants.
*/
.btn {
    padding: var(--space-md) var(--space-xl);
    border: 2px solid transparent;
    border-radius: var(--radius-lg);
    font-family: var(--font-primary);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-base);
    font-size: var(--font-size-sm);
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
    letter-spacing: var(--letter-spacing-wide);
    text-transform: uppercase;
    min-height: 48px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    backdrop-filter: blur(10px);
}

/* Button shimmer effect */
.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, 
        transparent, 
        rgba(255, 255, 255, 0.3), 
        transparent);
    transition: left var(--transition-slow);
    z-index: 1;
}

.btn:hover::before {
    left: 100%;
}

/* Button ripple effect */
.btn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.3s, height 0.3s;
    z-index: 0;
}

.btn:active::after {
    width: 300px;
    height: 300px;
}

.btn:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow: var(--shadow-xl);
}

.btn:active {
    transform: translateY(-1px) scale(0.98);
    box-shadow: var(--shadow-lg);
}

.btn:disabled {
    opacity: var(--disabled-opacity);
    cursor: not-allowed;
    transform: none;
    box-shadow: var(--shadow-sm);
}

/*
Button Variants
--------------------------------------------------------------------------
Different button styles for various use cases.
*/
.btn-primary {
    background: linear-gradient(135deg, 
        var(--color-primary-500), 
        var(--color-primary-600));
    color: white;
    border-color: var(--color-primary-600);
    box-shadow: 
        var(--shadow-md),
        0 0 20px rgba(225, 29, 72, 0.2);
}

.btn-primary:hover {
    background: linear-gradient(135deg, 
        var(--color-primary-600), 
        var(--color-primary-700));
    border-color: var(--color-primary-700);
    box-shadow: 
        var(--shadow-xl),
        0 0 30px rgba(225, 29, 72, 0.4);
}

.btn-secondary {
    background: linear-gradient(135deg, 
        var(--bg-primary), 
        var(--bg-tertiary));
    color: var(--text-primary);
    border-color: var(--border-color);
}

.btn-secondary:hover {
    background: linear-gradient(135deg, 
        var(--bg-tertiary), 
        var(--color-secondary-100));
    border-color: var(--color-secondary-300);
    color: var(--color-secondary-700);
}

.btn-success {
    background: linear-gradient(135deg, 
        var(--color-success-500), 
        var(--color-success-600));
    color: white;
    border-color: var(--color-success-600);
    box-shadow: 
        var(--shadow-md),
        0 0 20px rgba(16, 185, 129, 0.2);
}

.btn-success:hover {
    background: linear-gradient(135deg, 
        var(--color-success-600), 
        var(--color-success-700));
    border-color: var(--color-success-700);
    box-shadow: 
        var(--shadow-xl),
        0 0 30px rgba(16, 185, 129, 0.4);
}

.btn-warning {
    background: linear-gradient(135deg, 
        var(--color-warning-500), 
        var(--color-warning-600));
    color: white;
    border-color: var(--color-warning-600);
    box-shadow: 
        var(--shadow-md),
        0 0 20px rgba(245, 158, 11, 0.2);
}

.btn-warning:hover {
    background: linear-gradient(135deg, 
        var(--color-warning-600), 
        var(--color-accent-700));
    border-color: var(--color-accent-700);
    box-shadow: 
        var(--shadow-xl),
        0 0 30px rgba(245, 158, 11, 0.4);
}

.btn-error {
    background: linear-gradient(135deg, 
        var(--color-error-500), 
        var(--color-error-600));
    color: white;
    border-color: var(--color-error-600);
    box-shadow: 
        var(--shadow-md),
        0 0 20px rgba(239, 68, 68, 0.2);
}

.btn-error:hover {
    background: linear-gradient(135deg, 
        var(--color-error-600), 
        var(--color-error-700));
    border-color: var(--color-error-700);
    box-shadow: 
        var(--shadow-xl),
        0 0 30px rgba(239, 68, 68, 0.4);
}

/*
Button Sizes
--------------------------------------------------------------------------
Different button sizes for various contexts.
*/
.btn-sm {
    padding: var(--space-sm) var(--space-lg);
    font-size: var(--font-size-xs);
    min-height: 36px;
}

.btn-lg {
    padding: var(--space-lg) var(--space-2xl);
    font-size: var(--font-size-base);
    min-height: 56px;
}

/*
Form Elements
============================================================================ */

/*
Input Fields
--------------------------------------------------------------------------
Text inputs, selects, and other form controls.
*/
.select-input,
.search-input {
    padding: var(--space-md) var(--space-lg);
    border: 2px solid var(--border-color);
    background: linear-gradient(145deg, var(--bg-primary), var(--bg-secondary));
    border-radius: var(--radius-lg);
    font-family: var(--font-primary);
    font-size: var(--font-size-sm);
    color: var(--text-primary);
    transition: all var(--transition-base);
    letter-spacing: var(--letter-spacing-wide);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(10px);
    min-height: 48px;
}

.select-input:hover,
.search-input:hover {
    border-color: var(--color-primary-300);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.select-input:focus,
.search-input:focus {
    outline: none;
    border-color: var(--color-primary-500);
    box-shadow: 
        var(--shadow-lg),
        0 0 0 4px rgba(225, 29, 72, 0.1);
    transform: translateY(-2px);
    background: var(--bg-primary);
}

/*
Custom Select Styling
--------------------------------------------------------------------------
Enhanced select elements with custom arrows.
*/
.select-input,
.select-control {
    appearance: none;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='m6 8 4 4 4-4'/%3e%3c/svg%3e");
    background-position: right 12px center;
    background-repeat: no-repeat;
    background-size: 16px;
    padding-right: 40px;
}

.select-input:focus,
.select-control:focus {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%23e11d48' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='m6 8 4 4 4-4'/%3e%3c/svg%3e");
}

.select-control {
    padding: var(--space-sm) var(--space-md);
    min-width: 100px;
    font-weight: 500;
    padding-right: 32px;
    background-size: 14px;
    background-position: right 8px center;
}

/*
Search Input Enhancement
--------------------------------------------------------------------------
Search input with integrated icon.
*/
.search-container {
    position: relative;
}

.search-container::before {
    content: '🔍';
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 16px;
    color: var(--text-tertiary);
    z-index: 1;
    pointer-events: none;
}

.search-container .search-input {
    padding-left: 40px;
}

.search-input::placeholder {
    color: var(--text-tertiary);
    font-style: italic;
}

/* ============================================================================
   6. DARK THEME SYSTEM
   ============================================================================ */

/*
Dark Theme Variables
--------------------------------------------------------------------------
Complete dark theme color system with enhanced contrast.
*/
[data-theme="dark"] {
    /* Dark theme backgrounds */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    
    /* Dark theme text colors */
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-tertiary: #94a3b8;
    
    /* Dark theme borders */
    --border-color: #475569;
    
    /* Enhanced dark theme shadows with more depth */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.6);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.6), 0 1px 2px -1px rgb(0 0 0 / 0.6);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.6), 0 2px 4px -2px rgb(0 0 0 / 0.6);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.6), 0 4px 6px -4px rgb(0 0 0 / 0.6);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.6), 0 10px 10px -5px rgb(0 0 0 / 0.4);
    
    /* Dark theme specific color adjustments for better contrast */
    --color-primary-300: #fda4af;
    --color-primary-400: #fb7185;
    --color-primary-500: #f43f5e;
    
    --color-accent: #fbbf24;
    --color-accent-300: #fcd34d;
    --color-accent-400: #fbbf24;
    --color-accent-500: #f59e0b;
    
    --color-success: #34d399;
    --color-success-300: #6ee7b7;
    --color-success-400: #4ade80;
    --color-success-500: #22c55e;
    
    --color-warning: #fbbf24;
    --color-error: #f87171;
    --color-error-300: #fca5a5;
    --color-error-400: #f87171;
    --color-error-500: #ef4444;
    
    /* Dark theme specific secondary colors */
    --color-secondary-100: #475569;
    --color-secondary-200: #64748b;
    --color-secondary-300: #94a3b8;
    --color-secondary-600: #334155;
    --color-secondary-700: #1e293b;
    --color-secondary-800: #0f172a;
    --color-secondary-900: #020617;
}

/*
Dark Theme Component Overrides
--------------------------------------------------------------------------
Specific styling adjustments for dark theme.
*/

/* Background effects */
[data-theme="dark"] body::after {
    background: linear-gradient(135deg, 
        rgba(15, 23, 42, 0.98) 0%, 
        rgba(30, 41, 59, 0.95) 100%);
}

/* Header components */
[data-theme="dark"] .app-header {
    background: linear-gradient(145deg, 
        rgba(15, 23, 42, 0.95), 
        rgba(30, 41, 59, 0.9));
    border: 1px solid rgba(71, 85, 105, 0.6);
}

/* Navigation */
[data-theme="dark"] .nav-container {
    background: linear-gradient(145deg, 
        rgba(15, 23, 42, 0.95), 
        rgba(30, 41, 59, 0.9));
    border: 1px solid rgba(71, 85, 105, 0.6);
}

/* Content area */
[data-theme="dark"] .content-area {
    background: rgba(15, 23, 42, 0.95);
    border: 1px solid rgba(71, 85, 105, 0.6);
}

/* Theme toggle icons */
[data-theme="dark"] .theme-icon.light-icon {
    opacity: 0;
    transform: rotate(180deg) scale(0.5);
}

[data-theme="dark"] .theme-icon.dark-icon {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

/* Form elements in dark theme */
[data-theme="dark"] .select-input,
[data-theme="dark"] .select-control,
[data-theme="dark"] .search-input {
    background: linear-gradient(145deg, 
        var(--color-secondary-800), 
        var(--color-secondary-700));
    border-color: var(--color-secondary-600);
    color: var(--text-primary);
}

[data-theme="dark"] .btn-icon {
    background: linear-gradient(145deg, 
        var(--color-secondary-800), 
        var(--color-secondary-700));
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .btn-secondary {
    background: linear-gradient(135deg, 
        var(--color-secondary-700), 
        var(--color-secondary-800));
    color: var(--text-primary);
    border-color: var(--color-secondary-600);
}

/* Focus states for dark theme */
[data-theme="dark"] .btn:focus,
[data-theme="dark"] .nav-tab:focus,
[data-theme="dark"] .select-control:focus,
[data-theme="dark"] .select-input:focus,
[data-theme="dark"] .search-input:focus {
    box-shadow: var(--focus-ring-dark);
}

/* ============================================================================
   7. ANIMATION SYSTEM
   ============================================================================ */

/*
Core Animations
--------------------------------------------------------------------------
Essential animations used throughout the application.
*/

/* Page load animation */
@keyframes pageLoad {
    0% {
        opacity: 0;
        transform: translateY(20px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Tab panel reveal */
@keyframes tabPanelReveal {
    0% {
        opacity: 0;
        transform: translateY(30px) scale(0.95);
    }
    50% {
        opacity: 0.7;
        transform: translateY(10px) scale(0.98);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Content stagger animation */
@keyframes contentStagger {
    0% {
        opacity: 0;
        transform: translateY(20px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Gradient flow animation */
@keyframes gradientFlow {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

/* Gradient rotation */
@keyframes gradientRotate {
    0%, 100% { background-position: 0% 50%; }
    25% { background-position: 100% 50%; }
    50% { background-position: 100% 100%; }
    75% { background-position: 0% 100%; }
}

/* Shimmer effect */
@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

/* Spin animation */
@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Pulse animation */
@keyframes pulse {
    0%, 100% {
        transform: scale(1);
        opacity: 1;
    }
    50% {
        transform: scale(1.05);
        opacity: 0.9;
    }
}

/* Bounce animation */
@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-10px); }
    60% { transform: translateY(-5px); }
}

/* Float animation */
@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-10px) rotate(1deg); }
}

/*
Utility Animation Classes
--------------------------------------------------------------------------
Reusable animation classes for common effects.
*/
.fade-in { animation: pageLoad 0.6s ease-out; }
.pulse { animation: pulse 2s ease-in-out infinite; }
.float { animation: float 6s ease-in-out infinite; }
.spin { animation: spin 1s linear infinite; }

/* ============================================================================
   8. UTILITY CLASSES
   ============================================================================ */

/*
Color Utilities
--------------------------------------------------------------------------
Quick color application classes.
*/
.text-primary { color: var(--text-primary); }
.text-secondary { color: var(--text-secondary); }
.text-tertiary { color: var(--text-tertiary); }
.text-accent { color: var(--color-accent-500); }
.text-success { color: var(--color-success-500); }
.text-warning { color: var(--color-warning-500); }
.text-error { color: var(--color-error-500); }

.bg-primary { background-color: var(--bg-primary); }
.bg-secondary { background-color: var(--bg-secondary); }
.bg-tertiary { background-color: var(--bg-tertiary); }

/*
Layout Utilities
--------------------------------------------------------------------------
Common layout and positioning utilities.
*/
.w-full { width: 100%; }
.h-full { height: 100%; }
.flex { display: flex; }
.grid { display: grid; }
.hidden { display: none; }
.block { display: block; }
.inline-block { display: inline-block; }

.text-left { text-align: left; }
.text-center { text-align: center; }
.text-right { text-align: right; }

.cursor-pointer { cursor: pointer; }
.cursor-not-allowed { cursor: not-allowed; }

/*
Interactive Utilities
--------------------------------------------------------------------------
Classes for enhanced interactivity.
*/
.hover-lift {
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.hover-lift:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.hover-glow:hover {
    box-shadow: 0 0 20px rgba(225, 29, 72, 0.3);
}

.focus-ring:focus {
    outline: none;
    box-shadow: var(--focus-ring);
}

/* ============================================================================
   9. RESPONSIVE DESIGN
   ============================================================================ */

/*
Responsive Breakpoints
--------------------------------------------------------------------------
Mobile-first responsive design with progressive enhancement.
*/

/* Large screens (1024px and up) */
@media (min-width: 1024px) {
    .app-container {
        padding: var(--space-2xl);
    }
    
    .app-header {
        padding: var(--space-3xl);
    }
}

/* Tablet (768px to 1023px) */
@media (max-width: 1023px) and (min-width: 768px) {
    .app-container {
        padding: var(--space-lg);
    }
    
    .app-header {
        padding: var(--space-xl);
    }
    
    .header-content {
        flex-direction: column;
        gap: var(--space-lg);
    }
    
    .header-controls {
        flex-wrap: wrap;
        justify-content: center;
        gap: var(--space-sm);
    }
    
    /* Adjust font sizes for tablet */
    h1 { font-size: var(--font-size-4xl); }
    h2 { font-size: var(--font-size-3xl); }
    h3 { font-size: var(--font-size-2xl); }
}

/* Mobile landscape (481px to 767px) */
@media (max-width: 767px) and (min-width: 481px) {
    .app-container {
        padding: var(--space-md);
    }
    
    .app-header {
        padding: var(--space-lg);
    }
    
    /* Adjust typography for mobile landscape */
    h1 { font-size: var(--font-size-3xl); }
    h2 { font-size: var(--font-size-2xl); }
    h3 { font-size: var(--font-size-xl); }
    
    body {
        font-size: var(--font-size-sm);
        line-height: var(--line-height-normal);
    }
    
    .nav-tabs {
        flex-direction: column;
        gap: var(--space-xs);
    }
    
    .nav-tab {
        text-align: center;
        padding: var(--space-sm) var(--space-md);
        min-height: 44px;
        font-size: var(--font-size-xs);
    }
}

/* Mobile portrait (up to 480px) */
@media (max-width: 480px) {
    .app-container {
        padding: var(--space-sm);
    }
    
    .app-header {
        padding: var(--space-md);
    }
    
    .brand {
        flex-direction: column;
        text-align: center;
        gap: var(--space-md);
    }
    
    .header-controls {
        width: 100%;
        justify-content: center;
        gap: var(--space-sm);
    }
    
    /* Compact typography for small screens */
    h1 { 
        font-size: var(--font-size-2xl);
        line-height: var(--line-height-snug);
        margin-bottom: var(--space-sm);
    }
    
    h2 { 
        font-size: var(--font-size-xl);
        margin-bottom: var(--space-sm);
    }
    
    h3 { 
        font-size: var(--font-size-lg);
        margin-bottom: var(--space-xs);
    }
    
    body {
        font-size: var(--font-size-sm);
        line-height: var(--line-height-normal);
    }
    
    p {
        margin-bottom: var(--space-sm);
    }
    
    .btn {
        padding: var(--space-sm) var(--space-lg);
        font-size: var(--font-size-xs);
    }
    
    .nav-tab {
        padding: var(--space-sm);
        font-size: var(--font-size-xs);
    }
}

/*
Responsive Utilities
--------------------------------------------------------------------------
Responsive-specific utility classes.
*/
@media (max-width: 768px) {
    .mobile\:hidden { display: none; }
    .mobile\:block { display: block; }
    .mobile\:text-center { text-align: center; }
    .mobile\:p-sm { padding: var(--space-sm); }
    .mobile\:m-sm { margin: var(--space-sm); }
}

@media (min-width: 769px) {
    .desktop\:hidden { display: none; }
    .desktop\:block { display: block; }
    .desktop\:flex { display: flex; }
}

/* ============================================================================
   10. ACCESSIBILITY & PERFORMANCE
   ============================================================================ */

/*
Accessibility Enhancements
--------------------------------------------------------------------------
Improved accessibility for all users.
*/

/* Focus management */
.focus-trap {
    outline: none;
}

.focus-trap:focus-visible {
    outline: 2px solid var(--color-accent-500);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --shadow: 0 2px 4px 0 rgb(0 0 0 / 0.3);
        --shadow-md: 0 4px 8px 0 rgb(0 0 0 / 0.3);
        --shadow-lg: 0 8px 16px 0 rgb(0 0 0 / 0.3);
    }
    
    .btn {
        border: 2px solid currentColor;
    }
}

/* Reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/*
Performance Optimizations
--------------------------------------------------------------------------
GPU acceleration and performance hints.
*/
.gpu-accelerated {
    transform: translateZ(0);
    will-change: transform;
}

/* Smooth transitions for theme switching */
* {
    transition: background-color var(--transition-base), 
                color var(--transition-base), 
                border-color var(--transition-base),
                box-shadow var(--transition-base);
}

/*
Print Styles
--------------------------------------------------------------------------
Optimized styles for printing.
*/
@media print {
    .no-print {
        display: none !important;
    }
    
    * {
        animation: none !important;
        transition: none !important;
        box-shadow: none !important;
        text-shadow: none !important;
    }
    
    body {
        background: white !important;
        color: black !important;
    }
    
    .app-header,
    .nav-container {
        box-shadow: none !important;
        border: 1px solid #ccc !important;
    }
}

/*
Dark Theme Scrollbar
--------------------------------------------------------------------------
Custom scrollbar styling for dark theme.
*/
[data-theme="dark"] ::-webkit-scrollbar {
    width: 8px;
}

[data-theme="dark"] ::-webkit-scrollbar-track {
    background: var(--color-secondary-800);
}

[data-theme="dark"] ::-webkit-scrollbar-thumb {
    background: var(--color-secondary-600);
    border-radius: var(--radius-full);
}

[data-theme="dark"] ::-webkit-scrollbar-thumb:hover {
    background: var(--color-secondary-500);
}

/* Enhanced dark theme flashcards */
[data-theme="dark"] .flashcard {
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    border: 1px solid rgba(71, 85, 105, 0.3);
}

[data-theme="dark"] .flashcard:hover {
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.5);
    border-color: rgba(71, 85, 105, 0.5);
}

[data-theme="dark"] .card-front {
    background: linear-gradient(145deg, 
        var(--color-primary-600), 
        var(--color-primary-700));
    color: white;
}

[data-theme="dark"] .card-back {
    background: linear-gradient(145deg, 
        var(--color-secondary-800), 
        var(--color-secondary-900));
    color: white;
}

/* Enhanced dark theme buttons */
[data-theme="dark"] .btn-primary {
    background: linear-gradient(135deg, 
        var(--color-primary-600), 
        var(--color-primary-700));
    border-color: var(--color-primary-500);
}

[data-theme="dark"] .btn-primary:hover {
    background: linear-gradient(135deg, 
        var(--color-primary-500), 
        var(--color-primary-600));
    box-shadow: 0 4px 20px rgba(225, 29, 72, 0.3);
}

[data-theme="dark"] .btn-success {
    background: linear-gradient(135deg, 
        var(--color-success-600), 
        var(--color-success-700));
}

[data-theme="dark"] .btn-success:hover {
    background: linear-gradient(135deg, 
        var(--color-success-500), 
        var(--color-success-600));
}

[data-theme="dark"] .btn-error {
    background: linear-gradient(135deg, 
        var(--color-error-600), 
        var(--color-error-700));
}

[data-theme="dark"] .btn-error:hover {
    background: linear-gradient(135deg, 
        var(--color-error-500), 
        var(--color-error-600));
}

[data-theme="dark"] .btn-warning {
    background: linear-gradient(135deg, 
        var(--color-warning-600), 
        var(--color-warning-700));
}

[data-theme="dark"] .btn-warning:hover {
    background: linear-gradient(135deg, 
        var(--color-warning-500), 
        var(--color-warning-600));
}

/* Enhanced dark theme navigation */
[data-theme="dark"] .nav-tab {
    background: linear-gradient(135deg, 
        var(--color-secondary-800), 
        var(--color-secondary-700));
    color: var(--color-secondary-200);
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .nav-tab:hover {
    background: linear-gradient(135deg, 
        var(--color-secondary-700), 
        var(--color-secondary-600));
    color: white;
    transform: translateY(-2px);
}

[data-theme="dark"] .nav-tab.active {
    background: linear-gradient(135deg, 
        var(--color-primary-600), 
        var(--color-primary-700));
    color: white;
    box-shadow: 0 4px 20px rgba(225, 29, 72, 0.3);
}

/* Enhanced dark theme statistics */
[data-theme="dark"] .stat-card {
    background: linear-gradient(145deg, 
        var(--color-secondary-800), 
        var(--color-secondary-900));
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .stat-card:hover {
    background: linear-gradient(145deg, 
        var(--color-secondary-700), 
        var(--color-secondary-800));
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

/* Enhanced dark theme vocabulary cards */
[data-theme="dark"] .vocab-card {
    background: linear-gradient(145deg, 
        var(--color-secondary-800), 
        var(--color-secondary-900));
    border-color: var(--color-secondary-600);
    color: var(--color-secondary-100);
}

[data-theme="dark"] .vocab-card:hover {
    background: linear-gradient(145deg, 
        var(--color-secondary-700), 
        var(--color-secondary-800));
    border-color: var(--color-primary-500);
    transform: translateY(-2px);
}

/* Enhanced dark theme quiz interface */
[data-theme="dark"] .quiz-option {
    background: linear-gradient(145deg, 
        var(--color-secondary-800), 
        var(--color-secondary-900));
    border-color: var(--color-secondary-600);
    color: var(--color-secondary-100);
}

[data-theme="dark"] .quiz-option:hover {
    background: linear-gradient(145deg, 
        var(--color-secondary-700), 
        var(--color-secondary-800));
    border-color: var(--color-primary-500);
}

[data-theme="dark"] .quiz-option.selected {
    background: linear-gradient(135deg, 
        var(--color-primary-600), 
        var(--color-primary-700));
    border-color: var(--color-primary-400);
    color: white;
}

[data-theme="dark"] .quiz-option.correct {
    background: linear-gradient(135deg, 
        var(--color-success-600), 
        var(--color-success-700));
    border-color: var(--color-success-400);
}

[data-theme="dark"] .quiz-option.incorrect {
    background: linear-gradient(135deg, 
        var(--color-error-600), 
        var(--color-error-700));
    border-color: var(--color-error-400);
}

/* ============================================================================
   END OF ORGANIZED CSS SYSTEM
   ============================================================================ */

/*
Development Notes:
- This CSS system follows BEM-like naming conventions
- All colors use CSS custom properties for easy theming
- Responsive design uses mobile-first approach
- Animations are optimized for performance using transform and opacity
- Dark theme is fully supported with proper contrast ratios
- Accessibility features include focus management and reduced motion support
- The system is modular and can be easily extended

Maintenance Guidelines:
- Always use CSS custom properties for colors and spacing
- Follow the established naming conventions
- Test all changes in both light and dark themes
- Ensure responsive behavior on all screen sizes
- Validate accessibility with screen readers
- Keep animations performant and respectful of user preferences
*/
/* ====
===============================
   VOCABULARY BROWSE & SEARCH STYLES
   =================================== */

/* Browse Stats */
.browse-stats {
    padding: var(--space-sm) var(--space-md);
    background: var(--color-surface);
    border-radius: var(--border-radius-md);
    margin-bottom: var(--space-md);
    font-size: 0.875rem;
    color: var(--text-secondary);
    text-align: center;
    border: 1px solid var(--border-color);
}

/* Vocabulary Grid */
.vocabulary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--space-md);
    padding: var(--space-md) 0;
    min-height: 200px;
}

/* Vocabulary Item */
.vocab-item {
    background: var(--color-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: var(--space-lg);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    position: relative;
    overflow: hidden;
    animation: fadeInUp 0.5s ease-out forwards;
    opacity: 0;
    transform: translateY(20px);
}

.vocab-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary-300);
}

.vocab-item:active {
    transform: translateY(-2px);
}

/* Vocabulary Item Header */
.vocab-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--space-md);
}

.vocab-character {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary-600);
    font-family: 'Noto Sans SC', sans-serif;
    line-height: 1;
    transition: all 0.3s ease;
}

.vocab-character:hover {
    color: var(--color-primary-700);
    transform: scale(1.1);
}

.vocab-level-badge {
    background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-600));
    color: white;
    padding: 4px 8px;
    border-radius: var(--border-radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Vocabulary Content */
.vocab-content {
    margin-bottom: var(--space-md);
}

.vocab-pinyin {
    font-size: 1.25rem;
    color: var(--color-accent-600);
    font-weight: 500;
    margin-bottom: var(--space-sm);
    font-family: var(--font-family-primary);
}

.vocab-translation {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.5;
    font-weight: 400;
}

/* Vocabulary Actions */
.vocab-actions {
    display: flex;
    gap: var(--space-sm);
    justify-content: flex-end;
}

.vocab-action-btn {
    background: var(--color-gray-100);
    border: 1px solid var(--color-gray-300);
    border-radius: var(--border-radius-md);
    padding: 6px 12px;
    font-size: 0.875rem;
    cursor: pointer;
    transition: all 0.2s ease;
    color: var(--text-primary);
    font-weight: 500;
}

.vocab-action-btn:hover {
    background: var(--color-primary-500);
    color: white;
    border-color: var(--color-primary-500);
    transform: translateY(-1px);
}

/* Search Suggestions */
.search-suggestions {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-surface);
    border: 1px solid var(--border-color);
    border-top: none;
    border-radius: 0 0 var(--border-radius-md) var(--border-radius-md);
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    max-height: 200px;
    overflow-y: auto;
}

.search-suggestion-item {
    padding: var(--space-sm) var(--space-md);
    cursor: pointer;
    transition: background-color 0.2s ease;
    border-bottom: 1px solid var(--color-gray-100);
}

.search-suggestion-item:hover {
    background: var(--color-primary-50);
    color: var(--color-primary-700);
}

.search-suggestion-item:last-child {
    border-bottom: none;
}

/* Search Highlight */
.search-highlight {
    background: var(--color-accent-200);
    color: var(--color-accent-800);
    padding: 2px 4px;
    border-radius: 3px;
    font-weight: 600;
}

/* Browse Loading State */
.browse-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-xl);
    color: var(--text-secondary);
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--color-gray-200);
    border-top: 3px solid var(--color-primary-500);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: var(--space-md);
}

/* Empty States */
.browse-empty-state,
.search-no-results,
.browse-error-state {
    text-align: center;
    padding: var(--space-xl);
    color: var(--text-secondary);
}

.empty-state-icon,
.no-results-icon,
.error-icon {
    font-size: 3rem;
    margin-bottom: var(--space-md);
    opacity: 0.7;
}

.search-suggestions ul {
    list-style: none;
    padding: 0;
    margin: var(--space-sm) 0;
}

.search-suggestions li {
    padding: var(--space-xs) 0;
    color: var(--text-tertiary);
}

/* Pagination Controls */
.browse-pagination {
    margin-top: var(--space-lg);
    padding-top: var(--space-lg);
    border-top: 1px solid var(--border-color);
}

.pagination-controls {
    display: flex;
    justify-content: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-md);
}

.pagination-btn {
    background: var(--color-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    padding: var(--space-sm) var(--space-md);
    cursor: pointer;
    transition: all 0.2s ease;
    font-weight: 500;
    color: var(--text-primary);
}

.pagination-btn:hover {
    background: var(--color-primary-50);
    border-color: var(--color-primary-300);
    color: var(--color-primary-700);
}

.pagination-btn.active {
    background: var(--color-primary-500);
    color: white;
    border-color: var(--color-primary-500);
}

.pagination-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.pagination-info {
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Search Container Enhancements */
.search-container {
    position: relative;
    display: flex;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.search-container.search-focused .search-input {
    border-color: var(--color-primary-500);
    box-shadow: var(--focus-ring);
}

/* Animations */
@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Dark Theme Overrides */
[data-theme="dark"] .vocab-item {
    background: var(--color-secondary-800);
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .vocab-item:hover {
    border-color: var(--color-primary-400);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

[data-theme="dark"] .vocab-character {
    color: var(--color-primary-400);
}

[data-theme="dark"] .vocab-character:hover {
    color: var(--color-primary-300);
}

[data-theme="dark"] .vocab-action-btn {
    background: var(--color-secondary-700);
    border-color: var(--color-secondary-600);
    color: var(--text-primary);
}

[data-theme="dark"] .vocab-action-btn:hover {
    background: var(--color-primary-600);
    border-color: var(--color-primary-600);
}

[data-theme="dark"] .search-suggestions {
    background: var(--color-secondary-800);
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .search-suggestion-item:hover {
    background: var(--color-primary-900);
    color: var(--color-primary-300);
}

[data-theme="dark"] .browse-stats {
    background: var(--color-secondary-800);
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .pagination-btn {
    background: var(--color-secondary-800);
    border-color: var(--color-secondary-600);
    color: var(--text-primary);
}

[data-theme="dark"] .pagination-btn:hover {
    background: var(--color-primary-900);
    border-color: var(--color-primary-600);
    color: var(--color-primary-300);
}

/* Responsive Design */
@media (max-width: 768px) {
    .vocabulary-grid {
        grid-template-columns: 1fr;
        gap: var(--space-sm);
    }
    
    .search-container {
        flex-direction: column;
    }
    
    .vocab-item {
        padding: var(--space-md);
    }
    
    .vocab-character {
        font-size: 2rem;
    }
    
    .pagination-controls {
        flex-wrap: wrap;
        gap: var(--space-xs);
    }
    
    .pagination-btn {
        padding: var(--space-xs) var(--space-sm);
        font-size: 0.875rem;
    }
}

@media (max-width: 480px) {
    .vocab-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-sm);
    }
    
    .vocab-actions {
        justify-content: flex-start;
    }
    
    .vocab-character {
        font-size: 1.75rem;
    }
}/* ====
===============================
   WORD DETAILS MODAL STYLES
   =================================== */

.word-detail-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10000;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.word-detail-modal.modal-open {
    opacity: 1;
    visibility: visible;
}

.modal-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.modal-content {
    position: relative;
    background: var(--color-surface);
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-2xl);
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow: hidden;
    transform: scale(0.9) translateY(20px);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.word-detail-modal.modal-open .modal-content {
    transform: scale(1) translateY(0);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-lg);
    border-bottom: 1px solid var(--border-color);
    background: linear-gradient(135deg, var(--color-primary-50), var(--color-primary-100));
}

.modal-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary-700);
    font-family: 'Noto Sans SC', sans-serif;
    margin: 0;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    padding: var(--space-sm);
    border-radius: var(--border-radius-md);
    transition: all 0.2s ease;
}

.modal-close:hover {
    background: var(--color-gray-200);
    color: var(--text-primary);
}

.modal-body {
    padding: var(--space-lg);
    max-height: 60vh;
    overflow-y: auto;
}

.word-detail-section {
    margin-bottom: var(--space-lg);
}

.word-detail-section:last-child {
    margin-bottom: 0;
}

.word-detail-section h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: var(--space-sm);
}

.word-pinyin {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: 1.5rem;
    color: var(--color-accent-600);
    font-weight: 500;
}

.word-translation {
    font-size: 1.25rem;
    color: var(--text-primary);
    line-height: 1.5;
}

.word-level {
    display: inline-block;
    background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-600));
    color: white;
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--border-radius-full);
    font-weight: 600;
    font-size: 1rem;
}

.word-stats {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.btn-icon {
    background: var(--color-gray-100);
    border: 1px solid var(--color-gray-300);
    border-radius: var(--border-radius-md);
    padding: var(--space-xs);
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 1rem;
}

.btn-icon:hover {
    background: var(--color-primary-500);
    color: white;
    border-color: var(--color-primary-500);
}

.modal-footer {
    display: flex;
    gap: var(--space-sm);
    padding: var(--space-lg);
    border-top: 1px solid var(--border-color);
    background: var(--color-gray-50);
}

.modal-footer .btn {
    flex: 1;
}

/* Dark Theme Modal */
[data-theme="dark"] .modal-content {
    background: var(--color-secondary-800);
}

[data-theme="dark"] .modal-header {
    background: linear-gradient(135deg, var(--color-secondary-700), var(--color-secondary-600));
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .modal-header h2 {
    color: var(--color-primary-400);
}

[data-theme="dark"] .modal-close:hover {
    background: var(--color-secondary-600);
}

[data-theme="dark"] .modal-footer {
    background: var(--color-secondary-700);
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .btn-icon {
    background: var(--color-secondary-700);
    border-color: var(--color-secondary-600);
    color: var(--text-primary);
}

[data-theme="dark"] .btn-icon:hover {
    background: var(--color-primary-600);
    border-color: var(--color-primary-600);
}

/* Responsive Modal */
@media (max-width: 768px) {
    .modal-content {
        width: 95%;
        max-height: 90vh;
    }
    
    .modal-header {
        padding: var(--space-md);
    }
    
    .modal-header h2 {
        font-size: 2rem;
    }
    
    .modal-body {
        padding: var(--space-md);
    }
    
    .modal-footer {
        padding: var(--space-md);
        flex-direction: column;
    }
    
    .word-pinyin {
        font-size: 1.25rem;
    }
    
    .word-translation {
        font-size: 1.125rem;
    }
}/
* ===================================
   QUIZ SYSTEM STYLES
   =================================== */

/* Quiz Setup */
.quiz-setup {
    text-align: center;
    padding: var(--space-xl);
    background: var(--color-surface);
    border-radius: var(--border-radius-xl);
    border: 1px solid var(--border-color);
}

.quiz-setup h3 {
    color: var(--color-primary-600);
    margin-bottom: var(--space-lg);
    font-size: 1.75rem;
    font-weight: 600;
}

.quiz-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-lg);
    margin-bottom: var(--space-xl);
}

/* Quiz Container */
.quiz-container {
    background: var(--color-surface);
    border-radius: var(--border-radius-xl);
    border: 1px solid var(--border-color);
    overflow: hidden;
    animation: slideInUp 0.5s ease-out;
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-lg);
    background: linear-gradient(135deg, var(--color-primary-50), var(--color-primary-100));
    border-bottom: 1px solid var(--border-color);
}

.quiz-progress {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-primary-700);
}

.quiz-score {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-accent-600);
}

/* Quiz Content */
.quiz-content {
    padding: var(--space-xl);
}

.question-display {
    text-align: center;
    padding: var(--space-xl);
    margin-bottom: var(--space-xl);
    background: linear-gradient(135deg, var(--color-gray-50), var(--color-gray-100));
    border-radius: var(--border-radius-lg);
    border: 2px solid var(--color-primary-200);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary-700);
    font-family: 'Noto Sans SC', sans-serif;
    min-height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.question-display::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(225, 29, 72, 0.05) 1px, transparent 1px);
    background-size: 30px 30px;
    animation: backgroundFloat 20s linear infinite;
    pointer-events: none;
}

/* Quiz Options */
.quiz-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
}

.quiz-option {
    background: linear-gradient(145deg, var(--color-surface), var(--color-gray-50));
    border: 2px solid var(--color-gray-200);
    border-radius: var(--border-radius-lg);
    padding: var(--space-lg);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-size: 1.125rem;
    font-weight: 500;
    text-align: center;
    position: relative;
    overflow: hidden;
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.quiz-option:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary-300);
    background: linear-gradient(145deg, var(--color-primary-50), var(--color-primary-100));
}

.quiz-option.selected {
    background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-600));
    color: white;
    border-color: var(--color-primary-500);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.quiz-option.correct {
    background: linear-gradient(135deg, var(--color-success-500), var(--color-success-600));
    color: white;
    border-color: var(--color-success-500);
    animation: correctPulse 0.6s ease-out;
}

.quiz-option.incorrect {
    background: linear-gradient(135deg, var(--color-error-500), var(--color-error-600));
    color: white;
    border-color: var(--color-error-500);
    animation: incorrectShake 0.6s ease-out;
}

.quiz-option::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s ease;
}

.quiz-option:hover::before {
    left: 100%;
}

/* Quiz Actions */
.quiz-actions {
    display: flex;
    justify-content: center;
    gap: var(--space-md);
    padding: var(--space-lg);
    background: var(--color-gray-50);
    border-top: 1px solid var(--border-color);
}

.quiz-actions .btn {
    min-width: 120px;
    font-weight: 600;
}

/* Quiz Results */
.quiz-results {
    text-align: center;
    padding: var(--space-xl);
    background: var(--color-surface);
    border-radius: var(--border-radius-xl);
    border: 1px solid var(--border-color);
    animation: slideInUp 0.5s ease-out;
}

.quiz-results h3 {
    color: var(--color-primary-600);
    margin-bottom: var(--space-lg);
    font-size: 2rem;
    font-weight: 700;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-lg);
    margin-bottom: var(--space-xl);
}

.result-card {
    background: linear-gradient(135deg, var(--color-primary-50), var(--color-primary-100));
    border: 1px solid var(--color-primary-200);
    border-radius: var(--border-radius-lg);
    padding: var(--space-lg);
    text-align: center;
}

.result-label {
    font-size: 0.875rem;
    color: var(--color-primary-600);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: var(--space-sm);
}

.result-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary-700);
    font-family: 'JetBrains Mono', monospace;
}

/* Quiz Animations */
@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes correctPulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

@keyframes incorrectShake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

@keyframes backgroundFloat {
    0% { transform: translate(0, 0) rotate(0deg); }
    100% { transform: translate(30px, 30px) rotate(360deg); }
}

/* Dark Theme Quiz Styles */
[data-theme="dark"] .quiz-setup,
[data-theme="dark"] .quiz-container,
[data-theme="dark"] .quiz-results {
    background: var(--color-secondary-800);
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .quiz-header {
    background: linear-gradient(135deg, var(--color-secondary-700), var(--color-secondary-600));
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .quiz-progress {
    color: var(--color-primary-400);
}

[data-theme="dark"] .quiz-score {
    color: var(--color-accent-400);
}

[data-theme="dark"] .question-display {
    background: linear-gradient(135deg, var(--color-secondary-700), var(--color-secondary-600));
    border-color: var(--color-primary-500);
    color: var(--color-primary-400);
}

[data-theme="dark"] .quiz-option {
    background: linear-gradient(145deg, var(--color-secondary-800), var(--color-secondary-700));
    border-color: var(--color-secondary-600);
    color: var(--text-primary);
}

[data-theme="dark"] .quiz-option:hover {
    border-color: var(--color-primary-400);
    background: linear-gradient(145deg, var(--color-secondary-700), var(--color-secondary-600));
}

[data-theme="dark"] .quiz-option.selected {
    background: linear-gradient(135deg, var(--color-primary-600), var(--color-primary-700));
    border-color: var(--color-primary-600);
}

[data-theme="dark"] .quiz-option.correct {
    background: linear-gradient(135deg, var(--color-success-600), var(--color-success-700));
    border-color: var(--color-success-600);
}

[data-theme="dark"] .quiz-option.incorrect {
    background: linear-gradient(135deg, var(--color-error-600), var(--color-error-700));
    border-color: var(--color-error-600);
}

[data-theme="dark"] .quiz-actions {
    background: var(--color-secondary-700);
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .result-card {
    background: linear-gradient(135deg, var(--color-secondary-700), var(--color-secondary-600));
    border-color: var(--color-secondary-500);
}

[data-theme="dark"] .result-label {
    color: var(--color-primary-400);
}

[data-theme="dark"] .result-value {
    color: var(--color-primary-300);
}

/* Responsive Quiz Design */
@media (max-width: 768px) {
    .quiz-options {
        grid-template-columns: 1fr;
    }
    
    .quiz-header {
        flex-direction: column;
        gap: var(--space-sm);
        text-align: center;
    }
    
    .question-display {
        font-size: 2rem;
        padding: var(--space-lg);
        min-height: 100px;
    }
    
    .quiz-option {
        padding: var(--space-md);
        font-size: 1rem;
        min-height: 60px;
    }
    
    .results-grid {
        grid-template-columns: 1fr;
    }
    
    .result-value {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .quiz-content {
        padding: var(--space-lg);
    }
    
    .question-display {
        font-size: 1.5rem;
        padding: var(--space-md);
        min-height: 80px;
    }
    
    .quiz-actions {
        flex-direction: column;
    }
    
    .quiz-actions .btn {
        width: 100%;
    }
}/* =
==================================
   FOOTER STYLES
   =================================== */

.app-footer {
    background: var(--color-surface);
    border-top: 1px solid var(--border-color);
    padding: var(--space-md) 0;
    margin-top: auto;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-md);
}

.footer-main p {
    margin: 0;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.dev-signature {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.footer-logo {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--color-primary-200);
}

.signature-text {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    line-height: 1.4;
}

.signature-text p {
    margin: 0;
}

.signature-text .version {
    font-size: 0.7rem;
    opacity: 0.7;
}

/* Dark theme footer */
[data-theme="dark"] .app-footer {
    background: var(--color-secondary-800);
    border-color: var(--color-secondary-600);
}

[data-theme="dark"] .footer-logo {
    border-color: var(--color-primary-400);
}

/* Responsive footer */
@media (max-width: 768px) {
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .dev-signature {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-logo {
        width: 28px;
        height: 28px;
    }
}

/* ===================================
   FLASHCARD IMPROVEMENTS
   =================================== */

.character-large {
    font-size: 4rem;
    font-weight: 700;
    color: var(--color-primary-600);
    font-family: 'Noto Sans SC', sans-serif;
    margin-bottom: var(--space-md);
    text-align: center;
}

.pinyin-large {
    font-size: 1.5rem;
    color: var(--color-accent-600);
    font-weight: 500;
    margin-bottom: var(--space-sm);
    text-align: center;
}

.translation-large {
    font-size: 1.25rem;
    color: var(--text-primary);
    font-weight: 400;
    margin-bottom: var(--space-sm);
    text-align: center;
}

.level-badge {
    background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-600));
    color: white;
    padding: 4px 12px;
    border-radius: var(--border-radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    display: inline-block;
    margin-top: var(--space-sm);
}

/* Dark theme flashcard improvements */
[data-theme="dark"] .character-large {
    color: var(--color-primary-400);
}

[data-theme="dark"] .pinyin-large {
    color: var(--color-accent-400);
}/* =
==================================
   ADDITIONAL FIXES FOR CARDS AND TABS
   =================================== */

/* Ensure flashcard is visible and properly styled */
#flashcard {
    min-height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-surface);
    border: 2px solid var(--color-primary-200);
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-lg);
    cursor: pointer;
    transition: all 0.3s ease;
    margin: var(--space-lg) 0;
}

#flashcard:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
    border-color: var(--color-primary-300);
}

.card-front {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-xl);
    text-align: center;
}

/* Tab panels should be visible when active */
.tab-panel {
    display: none;
    padding: var(--space-lg);
    min-height: 400px;
}

.tab-panel.active {
    display: block;
    animation: fadeIn 0.3s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Ensure navigation tabs are properly styled */
.nav-tab {
    background: var(--color-gray-100);
    border: 1px solid var(--color-gray-300);
    color: var(--text-secondary);
    transition: all 0.2s ease;
}

.nav-tab.active {
    background: var(--color-primary-500);
    color: white;
    border-color: var(--color-primary-500);
}

.nav-tab:hover {
    background: var(--color-primary-100);
    color: var(--color-primary-700);
    border-color: var(--color-primary-300);
}

.nav-tab.active:hover {
    background: var(--color-primary-600);
    color: white;
}

/* Quiz option selected state */
.quiz-option.selected {
    background: var(--color-primary-500);
    color: white;
    border-color: var(--color-primary-500);
}

.quiz-option.correct {
    background: var(--color-success-500);
    color: white;
    border-color: var(--color-success-500);
}

.quiz-option.incorrect {
    background: var(--color-error-500);
    color: white;
    border-color: var(--color-error-500);
}

/* Dark theme adjustments */
[data-theme="dark"] #flashcard {
    background: var(--color-secondary-800);
    border-color: var(--color-primary-400);
}

[data-theme="dark"] .nav-tab {
    background: var(--color-secondary-700);
    border-color: var(--color-secondary-600);
    color: var(--text-primary);
}

[data-theme="dark"] .nav-tab.active {
    background: var(--color-primary-600);
    border-color: var(--color-primary-600);
}

[data-theme="dark"] .nav-tab:hover {
    background: var(--color-secondary-600);
    border-color: var(--color-primary-400);
}

/* Responsive improvements */
@media (max-width: 768px) {
    #flashcard {
        min-height: 250px;
        margin: var(--space-md) 0;
    }
    
    .character-large {
        font-size: 3rem;
    }
    
    .pinyin-large {
        font-size: 1.25rem;
    }
    
    .translation-large {
        font-size: 1.125rem;
    }
}/* ========
===========================
   IMPROVED HEADER STYLES - FIXED
   =================================== */
.app-header {
    background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-600)) !important;
    color: white !important;
    padding: var(--space-lg) 0 !important;
    box-shadow: var(--shadow-lg) !important;
    position: sticky !important;
    top: 0 !important;
    z-index: 100 !important;
    border-bottom: 3px solid var(--color-primary-700) !important;
}

.header-content {
    max-width: 1200px !important;
    margin: 0 auto !important;
    padding: 0 var(--space-md) !important;
    display: flex !important;
    justify-content: space-between !important;
    align-items: center !important;
    gap: var(--space-lg) !important;
}

.header-left {
    display: flex !important;
    align-items: center !important;
    gap: var(--space-lg) !important;
}

.app-logo {
    display: flex !important;
    align-items: center !important;
    gap: var(--space-md) !important;
    text-decoration: none !important;
    color: white !important;
    transition: all 0.3s ease !important;
}

.app-logo:hover {
    transform: translateY(-2px) !important;
    filter: brightness(1.1) !important;
}

.app-logo img {
    width: 48px !important;
    height: 48px !important;
    border-radius: 12px !important;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2) !important;
    transition: all 0.3s ease !important;
}

.app-logo:hover img {
    transform: scale(1.05) !important;
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.3) !important;
}

.app-title {
    display: flex !important;
    flex-direction: column !important;
    gap: 2px !important;
}

.app-title h1 {
    font-size: 1.75rem !important;
    font-weight: 700 !important;
    margin: 0 !important;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2) !important;
    color: white !important;
}

.app-subtitle {
    font-size: 0.875rem !important;
    opacity: 0.9 !important;
    font-weight: 400 !important;
    margin: 0 !important;
    color: white !important;
}

.header-center {
    flex: 1 !important;
    display: flex !important;
    justify-content: center !important;
}

.header-search {
    position: relative !important;
    max-width: 400px !important;
    width: 100% !important;
}

.header-search-input {
    width: 100% !important;
    padding: 12px 16px 12px 44px !important;
    border: 2px solid rgba(255, 255, 255, 0.2) !important;
    border-radius: 25px !important;
    background: rgba(255, 255, 255, 0.1) !important;
    color: white !important;
    font-size: 0.875rem !important;
    backdrop-filter: blur(10px) !important;
    transition: all 0.3s ease !important;
}

.header-search-input::placeholder {
    color: rgba(255, 255, 255, 0.7) !important;
}

.header-search-input:focus {
    outline: none !important;
    border-color: rgba(255, 255, 255, 0.5) !important;
    background: rgba(255, 255, 255, 0.15) !important;
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.1) !important;
}

.header-search-icon {
    position: absolute !important;
    left: 16px !important;
    top: 50% !important;
    transform: translateY(-50%) !important;
    color: rgba(255, 255, 255, 0.7) !important;
    font-size: 1rem !important;
}

.header-right {
    display: flex !important;
    align-items: center !important;
    gap: var(--space-md) !important;
}

.header-controls {
    display: flex !important;
    align-items: center !important;
    gap: var(--space-sm) !important;
}

.header-control {
    background: rgba(255, 255, 255, 0.1) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
    border-radius: 8px !important;
    padding: 8px 12px !important;
    color: white !important;
    font-size: 0.875rem !important;
    cursor: pointer !important;
    transition: all 0.3s ease !important;
    backdrop-filter: blur(10px) !important;
    display: flex !important;
    align-items: center !important;
    gap: 6px !important;
}

.header-control:hover {
    background: rgba(255, 255, 255, 0.2) !important;
    border-color: rgba(255, 255, 255, 0.4) !important;
    transform: translateY(-1px) !important;
}

.header-control.active {
    background: rgba(255, 255, 255, 0.25) !important;
    border-color: rgba(255, 255, 255, 0.5) !important;
}

.header-stats {
    display: flex !important;
    align-items: center !important;
    gap: var(--space-md) !important;
    font-size: 0.875rem !important;
}

.header-stat {
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
    gap: 2px !important;
}

.header-stat-value {
    font-weight: 700 !important;
    font-size: 1.125rem !important;
    color: white !important;
}

.header-stat-label {
    opacity: 0.8 !important;
    font-size: 0.75rem !important;
    text-transform: uppercase !important;
    letter-spacing: 0.5px !important;
    color: white !important;
}

.header-progress {
    width: 120px !important;
    height: 6px !important;
    background: rgba(255, 255, 255, 0.2) !important;
    border-radius: 3px !important;
    overflow: hidden !important;
    margin-top: 4px !important;
}

.header-progress-fill {
    height: 100% !important;
    background: linear-gradient(90deg, #10b981, #34d399) !important;
    border-radius: 3px !important;
    transition: width 0.5s ease !important;
}

/* Dark theme header adjustments */
[data-theme="dark"] .app-header {
    background: linear-gradient(135deg, var(--color-secondary-800), var(--color-secondary-700)) !important;
    border-color: var(--color-secondary-600) !important;
}

/* Responsive header */
@media (max-width: 1024px) {
    .header-center {
        display: none !important;
    }
    .header-stats {
        display: none !important;
    }
}

@media (max-width: 768px) {
    .app-header {
        padding: var(--space-md) 0 !important;
    }
    .header-content {
        flex-direction: column !important;
        gap: var(--space-md) !important;
    }
    .header-left {
        width: 100% !important;
        justify-content: center !important;
    }
    .header-right {
        width: 100% !important;
        justify-content: center !important;
    }
    .app-title h1 {
        font-size: 1.5rem !important;
    }
    .app-logo img {
        width: 40px !important;
        height: 40px !important;
    }
}

@media (max-width: 480px) {
    .header-controls {
        flex-wrap: wrap !important;
        justify-content: center !important;
    }
    .header-control {
        padding: 6px 10px !important;
        font-size: 0.8rem !important;
    }
    .app-title {
        text-align: center !important;
    }
}

/* Header animations */
@keyframes headerSlideIn {
    from {
        transform: translateY(-100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.app-header {
    animation: headerSlideIn 0.5s ease-out !important;
}

/* Navigation improvements */
.nav-tabs {
    background: rgba(255, 255, 255, 0.1) !important;
    border-radius: 12px !important;
    padding: 4px !important;
    backdrop-filter: blur(10px) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
}

.nav-tab {
    background: transparent !important;
    border: none !important;
    color: rgba(255, 255, 255, 0.8) !important;
    padding: 10px 16px !important;
    border-radius: 8px !important;
    font-size: 0.875rem !important;
    font-weight: 500 !important;
    cursor: pointer !important;
    transition: all 0.3s ease !important;
    position: relative !important;
    overflow: hidden !important;
}

.nav-tab::before {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: -100% !important;
    width: 100% !important;
    height: 100% !important;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.1), transparent) !important;
    transition: left 0.5s ease !important;
}

.nav-tab:hover::before {
    left: 100% !important;
}

.nav-tab:hover {
    color: white !important;
    background: rgba(255, 255, 255, 0.1) !important;
    transform: translateY(-1px) !important;
}

.nav-tab.active {
    background: rgba(255, 255, 255, 0.2) !important;
    color: white !important;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1) !important;
}

.nav-tab.active::after {
    content: '' !important;
    position: absolute !important;
    bottom: 0 !important;
    left: 50% !important;
    transform: translateX(-50%) !important;
    width: 20px !important;
    height: 2px !important;
    background: white !important;
    border-radius: 1px !important;
}

/* Vocabulary grid styles */
.vocabulary-grid {
    display: grid !important;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)) !important;
    gap: var(--space-md) !important;
    padding: var(--space-md) 0 !important;
}

.vocab-card {
    background: var(--color-surface) !important;
    border: 1px solid var(--color-border) !important;
    border-radius: 12px !important;
    padding: var(--space-md) !important;
    cursor: pointer !important;
    transition: all 0.3s ease !important;
}

.vocab-card:hover {
    transform: translateY(-2px) !important;
    box-shadow: var(--shadow-lg) !important;
    border-color: var(--color-primary-300) !important;
}

.vocab-character {
    font-size: 2rem !important;
    font-weight: 700 !important;
    color: var(--color-primary-600) !important;
    text-align: center !important;
    margin-bottom: var(--space-sm) !important;
}

.vocab-pinyin {
    font-size: 1.125rem !important;
    color: var(--color-accent-600) !important;
    text-align: center !important;
    margin-bottom: var(--space-sm) !important;
}

.vocab-meaning {
    font-size: 0.875rem !important;
    color: var(--text-secondary) !important;
    text-align: center !important;
    margin-bottom: var(--space-sm) !important;
}

.vocab-level {
    font-size: 0.75rem !important;
    color: var(--color-primary-500) !important;
    text-align: center !important;
    font-weight: 600 !important;
    background: var(--color-primary-50) !important;
    padding: 2px 8px !important;
    border-radius: 12px !important;
    display: inline-block !important;
    margin: 0 auto !important;
}

/* Quiz option styles */
.quiz-option {
    display: block !important;
    width: 100% !important;
    padding: var(--space-md) !important;
    margin-bottom: var(--space-sm) !important;
    background: var(--color-surface) !important;
    border: 2px solid var(--color-border) !important;
    border-radius: 8px !important;
    cursor: pointer !important;
    transition: all 0.3s ease !important;
    font-size: 1rem !important;
    text-align: left !important;
}

.quiz-option:hover {
    border-color: var(--color-primary-300) !important;
    background: var(--color-primary-50) !important;
}

.quiz-option.selected {
    border-color: var(--color-primary-500) !important;
    background: var(--color-primary-100) !important;
}

.quiz-option.correct {
    border-color: var(--color-success-500) !important;
    background: var(--color-success-100) !important;
    color: var(--color-success-700) !important;
}

.quiz-option.incorrect {
    border-color: var(--color-error-500) !important;
    background: var(--color-error-100) !important;
    color: var(--color-error-700) !important;
}

/* Level progress styles */
.level-progress-item {
    display: flex !important;
    align-items: center !important;
    gap: var(--space-md) !important;
    margin-bottom: var(--space-sm) !important;
}

.level-label {
    min-width: 60px !important;
    font-weight: 600 !important;
    color: var(--text-primary) !important;
}

.level-progress-item .progress-bar {
    flex: 1 !important;
    height: 8px !important;
    background: var(--color-gray-200) !important;
    border-radius: 4px !important;
    overflow: hidden !important;
}

.level-progress-item .progress-fill {
    height: 100% !important;
    background: linear-gradient(90deg, var(--color-primary-500), var(--color-primary-400)) !important;
    border-radius: 4px !important;
    transition: width 0.5s ease !important;
}

.level-progress-item .progress-text {
    min-width: 60px !important;
    font-size: 0.875rem !important;
    color: var(--text-secondary) !important;
    text-align: right !important;
}/*
 ===================================
   IMPROVED BODY AND MAIN CONTENT STYLES
   =================================== */

/* Enhanced body styling */
body {
    margin: 0 !important;
    padding: 0 !important;
    min-height: 100vh !important;
    font-family: var(--font-primary) !important;
    background: linear-gradient(135deg, 
        var(--color-secondary-50) 0%, 
        var(--color-primary-50) 50%, 
        var(--color-accent-50) 100%) !important;
    color: var(--text-primary) !important;
    line-height: 1.6 !important;
    overflow-x: hidden !important;
}

/* Enhanced app container */
.app-container {
    min-height: 100vh !important;
    display: flex !important;
    flex-direction: column !important;
    position: relative !important;
}

/* Main content area improvements */
.main-content {
    flex: 1 !important;
    padding: var(--space-xl) 0 !important;
    background: transparent !important;
    position: relative !important;
}

.content-wrapper {
    max-width: 1200px !important;
    margin: 0 auto !important;
    padding: 0 var(--space-lg) !important;
    position: relative !important;
}

/* Enhanced navigation container */
.nav-container {
    background: rgba(255, 255, 255, 0.95) !important;
    backdrop-filter: blur(20px) !important;
    border: 1px solid rgba(226, 232, 240, 0.6) !important;
    border-radius: 20px !important;
    padding: var(--space-md) !important;
    margin: var(--space-lg) auto !important;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1) !important;
    position: relative !important;
    overflow: hidden !important;
    max-width: 800px !important;
}

.nav-container::before {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    height: 3px !important;
    background: linear-gradient(90deg, 
        var(--color-primary-500), 
        var(--color-accent-500), 
        var(--color-success-500)) !important;
    background-size: 200% 100% !important;
    animation: gradientFlow 3s ease infinite !important;
}

.nav-tabs {
    display: flex !important;
    gap: var(--space-sm) !important;
    position: relative !important;
    background: rgba(255, 255, 255, 0.5) !important;
    border-radius: 16px !important;
    padding: var(--space-sm) !important;
}

.nav-tab {
    flex: 1 !important;
    padding: var(--space-md) var(--space-lg) !important;
    border: none !important;
    background: transparent !important;
    border-radius: 12px !important;
    color: var(--text-secondary) !important;
    font-family: var(--font-primary) !important;
    font-weight: 600 !important;
    cursor: pointer !important;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1) !important;
    font-size: var(--font-size-sm) !important;
    position: relative !important;
    overflow: hidden !important;
    letter-spacing: 0.5px !important;
    text-transform: uppercase !important;
    min-height: 48px !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
}

.nav-tab::before {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.2), 
        rgba(255, 255, 255, 0.1)) !important;
    transform: translateX(-100%) !important;
    transition: transform 0.5s ease !important;
    border-radius: 12px !important;
}

.nav-tab:hover::before {
    transform: translateX(0) !important;
}

.nav-tab:hover {
    color: var(--text-primary) !important;
    transform: translateY(-2px) scale(1.02) !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15) !important;
}

.nav-tab.active {
    background: linear-gradient(135deg, 
        var(--color-primary-500), 
        var(--color-primary-600)) !important;
    color: white !important;
    box-shadow: 
        0 10px 30px rgba(225, 29, 72, 0.4),
        0 0 0 1px rgba(255, 255, 255, 0.2) inset !important;
    transform: translateY(-3px) scale(1.05) !important;
    position: relative !important;
    z-index: 2 !important;
}

.nav-tab.active::before {
    display: none !important;
}

.nav-tab.active::after {
    content: '' !important;
    position: absolute !important;
    bottom: -8px !important;
    left: 50% !important;
    transform: translateX(-50%) !important;
    width: 40% !important;
    height: 4px !important;
    background: linear-gradient(90deg, 
        var(--color-accent-500), 
        var(--color-accent-400)) !important;
    border-radius: 2px !important;
    box-shadow: 0 2px 8px rgba(245, 158, 11, 0.5) !important;
}

/* Enhanced tab panels */
.tab-panel {
    display: none !important;
    opacity: 0 !important;
    transform: translateY(20px) !important;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1) !important;
    background: rgba(255, 255, 255, 0.95) !important;
    backdrop-filter: blur(20px) !important;
    border-radius: 20px !important;
    padding: var(--space-2xl) !important;
    margin-top: var(--space-xl) !important;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
    position: relative !important;
    overflow: hidden !important;
}

.tab-panel::before {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.1) 0%, 
        rgba(255, 255, 255, 0.05) 100%) !important;
    pointer-events: none !important;
}

.tab-panel.active {
    display: block !important;
    animation: tabPanelReveal 0.6s cubic-bezier(0.16, 1, 0.3, 1) forwards !important;
}

/* Enhanced flashcard section */
.flashcard-section {
    margin: var(--space-2xl) 0 !important;
    position: relative !important;
}

.flashcard-container {
    perspective: 1000px !important;
    -webkit-perspective: 1000px !important;
    margin: var(--space-xl) auto !important;
    max-width: 600px !important;
    height: 400px !important;
    position: relative !important;
}

.flashcard {
    width: 100% !important;
    height: 100% !important;
    position: relative !important;
    cursor: pointer !important;
    transition: transform 0.2s ease !important;
}

.flashcard:hover {
    transform: scale(1.02) !important;
}

.flashcard-inner {
    width: 100% !important;
    height: 100% !important;
    position: relative !important;
    transform-style: preserve-3d !important;
    -webkit-transform-style: preserve-3d !important;
    transition: transform 0.6s ease-in-out !important;
    -webkit-transition: -webkit-transform 0.6s ease-in-out !important;
}

.flashcard.flipped .flashcard-inner {
    transform: rotateY(180deg) !important;
    -webkit-transform: rotateY(180deg) !important;
}

.card-face {
    position: absolute !important;
    width: 100% !important;
    height: 100% !important;
    -webkit-backface-visibility: hidden !important;
    backface-visibility: hidden !important;
    border-radius: 20px !important;
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
    justify-content: center !important;
    padding: var(--space-2xl) !important;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
    position: relative !important;
    overflow: hidden !important;
}

.card-face::before {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.1) 0%, 
        rgba(255, 255, 255, 0.05) 100%) !important;
    pointer-events: none !important;
}

.card-front {
    background: linear-gradient(135deg, 
        var(--color-primary-500), 
        var(--color-primary-600)) !important;
    color: white !important;
    transform: rotateY(0deg) !important;
    -webkit-transform: rotateY(0deg) !important;
}

.card-back {
    background: linear-gradient(135deg, 
        var(--color-accent-500), 
        var(--color-accent-600)) !important;
    color: white !important;
    transform: rotateY(180deg) !important;
    -webkit-transform: rotateY(180deg) !important;
}

.card-character {
    font-size: clamp(3rem, 8vw, 6rem) !important;
    font-weight: 700 !important;
    margin-bottom: var(--space-lg) !important;
    text-shadow: 0 4px 8px rgba(0, 0, 0, 0.3) !important;
    font-family: var(--font-chinese) !important;
    letter-spacing: 0.1em !important;
    position: relative !important;
    z-index: 2 !important;
}

.card-hint {
    font-size: var(--font-size-lg) !important;
    opacity: 0.9 !important;
    text-align: center !important;
    margin-top: var(--space-md) !important;
    font-weight: 400 !important;
    position: relative !important;
    z-index: 2 !important;
}

.card-info {
    text-align: center !important;
    position: relative !important;
    z-index: 2 !important;
}

.word-info {
    display: flex !important;
    flex-direction: column !important;
    gap: var(--space-md) !important;
    align-items: center !important;
}

.word-info .character {
    font-size: 3rem !important;
    font-weight: 700 !important;
    font-family: var(--font-chinese) !important;
}

.word-info .pinyin {
    font-size: 1.5rem !important;
    font-weight: 500 !important;
    opacity: 0.9 !important;
}

.word-info .meaning {
    font-size: 1.25rem !important;
    font-weight: 400 !important;
    opacity: 0.8 !important;
}

.word-info .level {
    background: rgba(255, 255, 255, 0.2) !important;
    padding: var(--space-xs) var(--space-sm) !important;
    border-radius: 20px !important;
    font-size: var(--font-size-sm) !important;
    font-weight: 600 !important;
    text-transform: uppercase !important;
    letter-spacing: 0.5px !important;
}

/* Enhanced action buttons */
.action-buttons {
    display: flex !important;
    gap: var(--space-md) !important;
    justify-content: center !important;
    margin: var(--space-xl) 0 !important;
    flex-wrap: wrap !important;
}

.btn {
    padding: var(--space-md) var(--space-xl) !important;
    border: none !important;
    border-radius: 12px !important;
    font-family: var(--font-primary) !important;
    font-weight: 600 !important;
    cursor: pointer !important;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1) !important;
    font-size: var(--font-size-sm) !important;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1) !important;
    position: relative !important;
    overflow: hidden !important;
    letter-spacing: 0.5px !important;
    text-transform: uppercase !important;
    min-height: 48px !important;
    display: inline-flex !important;
    align-items: center !important;
    justify-content: center !important;
    gap: var(--space-xs) !important;
    backdrop-filter: blur(10px) !important;
    min-width: 120px !important;
}

.btn::before {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: -100% !important;
    width: 100% !important;
    height: 100% !important;
    background: linear-gradient(90deg, 
        transparent, 
        rgba(255, 255, 255, 0.3), 
        transparent) !important;
    transition: left 0.5s ease !important;
    z-index: 1 !important;
}

.btn:hover::before {
    left: 100% !important;
}

.btn:hover {
    transform: translateY(-3px) scale(1.05) !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2) !important;
}

.btn:active {
    transform: translateY(-1px) scale(0.98) !important;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.15) !important;
}

.btn:disabled {
    opacity: 0.6 !important;
    cursor: not-allowed !important;
    transform: none !important;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1) !important;
}

.btn-primary {
    background: linear-gradient(135deg, 
        var(--color-primary-500), 
        var(--color-primary-600)) !important;
    color: white !important;
}

.btn-primary:hover {
    background: linear-gradient(135deg, 
        var(--color-primary-600), 
        var(--color-primary-700)) !important;
}

.btn-secondary {
    background: linear-gradient(135deg, 
        var(--color-secondary-100), 
        var(--color-secondary-200)) !important;
    color: var(--text-primary) !important;
    border: 1px solid var(--color-secondary-300) !important;
}

.btn-secondary:hover {
    background: linear-gradient(135deg, 
        var(--color-secondary-200), 
        var(--color-secondary-300)) !important;
    border-color: var(--color-secondary-400) !important;
}

.btn-success {
    background: linear-gradient(135deg, 
        var(--color-success-500), 
        var(--color-success-600)) !important;
    color: white !important;
}

.btn-error {
    background: linear-gradient(135deg, 
        var(--color-error-500), 
        var(--color-error-600)) !important;
    color: white !important;
}

.btn-warning {
    background: linear-gradient(135deg, 
        var(--color-warning-500), 
        var(--color-warning-600)) !important;
    color: white !important;
}

/* Enhanced progress section */
.progress-section {
    margin-top: var(--space-2xl) !important;
    text-align: center !important;
}

.progress-bar {
    width: 100% !important;
    height: 12px !important;
    background: rgba(0, 0, 0, 0.1) !important;
    border-radius: 6px !important;
    overflow: hidden !important;
    margin-bottom: var(--space-md) !important;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1) !important;
}

.progress-fill {
    height: 100% !important;
    background: linear-gradient(90deg, 
        var(--color-success-500), 
        var(--color-success-400)) !important;
    border-radius: 6px !important;
    transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1) !important;
    box-shadow: 0 2px 8px rgba(16, 185, 129, 0.4) !important;
    position: relative !important;
}

.progress-fill::after {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    background: linear-gradient(90deg, 
        transparent, 
        rgba(255, 255, 255, 0.3), 
        transparent) !important;
    animation: progressShimmer 2s ease-in-out infinite !important;
}

.progress-text {
    font-size: var(--font-size-lg) !important;
    font-weight: 600 !important;
    color: var(--text-primary) !important;
}

/* Enhanced practice controls */
.practice-controls {
    background: rgba(255, 255, 255, 0.8) !important;
    backdrop-filter: blur(10px) !important;
    border-radius: 16px !important;
    padding: var(--space-xl) !important;
    margin-bottom: var(--space-xl) !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
}

.control-group {
    margin-bottom: var(--space-lg) !important;
}

.control-label {
    display: block !important;
    font-weight: 600 !important;
    color: var(--text-primary) !important;
    margin-bottom: var(--space-sm) !important;
    font-size: var(--font-size-sm) !important;
    text-transform: uppercase !important;
    letter-spacing: 0.5px !important;
}

.select-input {
    width: 100% !important;
    padding: var(--space-md) !important;
    border: 2px solid var(--color-border) !important;
    border-radius: 8px !important;
    background: rgba(255, 255, 255, 0.9) !important;
    color: var(--text-primary) !important;
    font-size: var(--font-size-sm) !important;
    transition: all 0.3s ease !important;
    cursor: pointer !important;
    backdrop-filter: blur(5px) !important;
}

.select-input:hover {
    border-color: var(--color-primary-300) !important;
    box-shadow: 0 0 0 3px rgba(225, 29, 72, 0.1) !important;
}

.select-input:focus {
    outline: none !important;
    border-color: var(--color-primary-500) !important;
    box-shadow: 0 0 0 3px rgba(225, 29, 72, 0.2) !important;
}

.practice-modes {
    display: grid !important;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)) !important;
    gap: var(--space-md) !important;
}

.mode-option {
    display: flex !important;
    align-items: center !important;
    gap: var(--space-sm) !important;
    padding: var(--space-md) !important;
    background: rgba(255, 255, 255, 0.6) !important;
    border-radius: 8px !important;
    cursor: pointer !important;
    transition: all 0.3s ease !important;
    border: 2px solid transparent !important;
}

.mode-option:hover {
    background: rgba(255, 255, 255, 0.8) !important;
    border-color: var(--color-primary-200) !important;
}

.mode-option input[type="radio"] {
    margin: 0 !important;
    cursor: pointer !important;
}

.mode-option label {
    cursor: pointer !important;
    font-weight: 500 !important;
    color: var(--text-primary) !important;
    margin: 0 !important;
}

.mode-option:has(input:checked) {
    background: var(--color-primary-50) !important;
    border-color: var(--color-primary-500) !important;
    box-shadow: 0 0 0 3px rgba(225, 29, 72, 0.1) !important;
}

/* Enhanced footer */
.app-footer {
    background: linear-gradient(135deg, 
        var(--color-secondary-800), 
        var(--color-secondary-900)) !important;
    color: white !important;
    padding: var(--space-2xl) 0 !important;
    margin-top: var(--space-3xl) !important;
    position: relative !important;
    overflow: hidden !important;
}

.app-footer::before {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    height: 3px !important;
    background: linear-gradient(90deg, 
        var(--color-primary-500), 
        var(--color-accent-500), 
        var(--color-success-500)) !important;
    background-size: 200% 100% !important;
    animation: gradientFlow 3s ease infinite !important;
}

.footer-content {
    max-width: 1200px !important;
    margin: 0 auto !important;
    padding: 0 var(--space-lg) !important;
    display: flex !important;
    justify-content: space-between !important;
    align-items: center !important;
    flex-wrap: wrap !important;
    gap: var(--space-lg) !important;
}

.footer-main p {
    font-size: var(--font-size-lg) !important;
    margin: 0 !important;
    opacity: 0.9 !important;
}

.dev-signature {
    display: flex !important;
    align-items: center !important;
    gap: var(--space-md) !important;
}

.footer-logo {
    width: 32px !important;
    height: 32px !important;
    border-radius: 6px !important;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3) !important;
}

.signature-text p {
    margin: 0 !important;
    font-size: var(--font-size-sm) !important;
    opacity: 0.8 !important;
}

.signature-text .version {
    font-size: var(--font-size-xs) !important;
    opacity: 0.6 !important;
    font-style: italic !important;
}

/* Animations */
@keyframes tabPanelReveal {
    0% {
        opacity: 0;
        transform: translateY(30px) scale(0.95);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@keyframes gradientFlow {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

@keyframes progressShimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

/* Dark theme adjustments */
[data-theme="dark"] .tab-panel {
    background: rgba(15, 23, 42, 0.95) !important;
    border-color: rgba(71, 85, 105, 0.3) !important;
}

[data-theme="dark"] .nav-container {
    background: rgba(15, 23, 42, 0.95) !important;
    border-color: rgba(71, 85, 105, 0.3) !important;
}

[data-theme="dark"] .practice-controls {
    background: rgba(15, 23, 42, 0.8) !important;
    border-color: rgba(71, 85, 105, 0.3) !important;
}

[data-theme="dark"] .mode-option {
    background: rgba(71, 85, 105, 0.3) !important;
    color: white !important;
}

[data-theme="dark"] .mode-option:hover {
    background: rgba(71, 85, 105, 0.5) !important;
}

[data-theme="dark"] .select-input {
    background: rgba(15, 23, 42, 0.9) !important;
    border-color: rgba(71, 85, 105, 0.5) !important;
    color: white !important;
}

/* Responsive improvements */
@media (max-width: 768px) {
    .content-wrapper {
        padding: 0 var(--space-md) !important;
    }
    
    .tab-panel {
        padding: var(--space-lg) !important;
        margin-top: var(--space-md) !important;
    }
    
    .flashcard-container {
        height: 300px !important;
        max-width: 100% !important;
    }
    
    .card-character {
        font-size: clamp(2rem, 6vw, 4rem) !important;
    }
    
    .action-buttons {
        flex-direction: column !important;
        align-items: center !important;
    }
    
    .btn {
        width: 100% !important;
        max-width: 300px !important;
    }
    
    .practice-modes {
        grid-template-columns: 1fr !important;
    }
    
    .footer-content {
        flex-direction: column !important;
        text-align: center !important;
    }
}

@media (max-width: 480px) {
    .nav-container {
        margin: var(--space-md) auto !important;
        padding: var(--space-sm) !important;
    }
    
    .nav-tab {
        padding: var(--space-sm) !important;
        font-size: var(--font-size-xs) !important;
    }
    
    .flashcard-container {
        height: 250px !important;
    }
    
    .card-face {
        padding: var(--space-lg) !important;
    }
}/* =======
============================
   WELCOME MESSAGE AND ADDITIONAL COMPONENTS
   =================================== */

/* Welcome message styling */
.welcome-message {
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.95), 
        rgba(248, 250, 252, 0.9)) !important;
    backdrop-filter: blur(20px) !important;
    border-radius: 20px !important;
    padding: var(--space-3xl) !important;
    margin-bottom: var(--space-xl) !important;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
    text-align: center !important;
    position: relative !important;
    overflow: hidden !important;
}

.welcome-message::before {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    height: 4px !important;
    background: linear-gradient(90deg, 
        var(--color-primary-500), 
        var(--color-accent-500), 
        var(--color-success-500)) !important;
    background-size: 200% 100% !important;
    animation: gradientFlow 3s ease infinite !important;
}

.welcome-content h2 {
    font-size: clamp(2rem, 5vw, 3rem) !important;
    font-weight: 700 !important;
    background: linear-gradient(135deg, 
        var(--color-primary-600), 
        var(--color-accent-600)) !important;
    -webkit-background-clip: text !important;
    -webkit-text-fill-color: transparent !important;
    background-clip: text !important;
    margin-bottom: var(--space-md) !important;
}

.welcome-content p {
    font-size: var(--font-size-lg) !important;
    color: var(--text-secondary) !important;
    margin-bottom: var(--space-xl) !important;
}

.welcome-stats {
    display: flex !important;
    justify-content: center !important;
    gap: var(--space-xl) !important;
    margin-bottom: var(--space-xl) !important;
    flex-wrap: wrap !important;
}

.welcome-stat {
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
    gap: var(--space-xs) !important;
    padding: var(--space-lg) !important;
    background: rgba(255, 255, 255, 0.6) !important;
    border-radius: 12px !important;
    backdrop-filter: blur(10px) !important;
    border: 1px solid rgba(255, 255, 255, 0.3) !important;
    min-width: 120px !important;
}

.stat-number {
    font-size: 2rem !important;
    font-weight: 700 !important;
    color: var(--color-primary-600) !important;
}

.stat-label {
    font-size: var(--font-size-sm) !important;
    color: var(--text-secondary) !important;
    text-transform: uppercase !important;
    letter-spacing: 0.5px !important;
    font-weight: 500 !important;
}

/* Enhanced search section */
.search-section {
    background: rgba(255, 255, 255, 0.8) !important;
    backdrop-filter: blur(10px) !important;
    border-radius: 16px !important;
    padding: var(--space-xl) !important;
    margin-bottom: var(--space-xl) !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
}

.search-container {
    display: flex !important;
    gap: var(--space-md) !important;
    align-items: center !important;
    flex-wrap: wrap !important;
}

.search-input {
    flex: 1 !important;
    padding: var(--space-md) var(--space-lg) !important;
    border: 2px solid var(--color-border) !important;
    border-radius: 12px !important;
    background: rgba(255, 255, 255, 0.9) !important;
    color: var(--text-primary) !important;
    font-size: var(--font-size-base) !important;
    transition: all 0.3s ease !important;
    backdrop-filter: blur(5px) !important;
    min-width: 250px !important;
}

.search-input:focus {
    outline: none !important;
    border-color: var(--color-primary-500) !important;
    box-shadow: 0 0 0 3px rgba(225, 29, 72, 0.2) !important;
    background: white !important;
}

.search-input::placeholder {
    color: var(--text-tertiary) !important;
}

.browse-stats {
    text-align: center !important;
    padding: var(--space-md) !important;
    font-size: var(--font-size-sm) !important;
    color: var(--text-secondary) !important;
    background: rgba(255, 255, 255, 0.6) !important;
    border-radius: 8px !important;
    margin-bottom: var(--space-lg) !important;
    backdrop-filter: blur(5px) !important;
}

/* Enhanced quiz setup */
.quiz-setup {
    text-align: center !important;
}

.quiz-setup h3 {
    font-size: var(--font-size-2xl) !important;
    font-weight: 700 !important;
    color: var(--text-primary) !important;
    margin-bottom: var(--space-xl) !important;
}

.quiz-options {
    display: grid !important;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)) !important;
    gap: var(--space-lg) !important;
    margin-bottom: var(--space-xl) !important;
}

/* Enhanced quiz container */
.quiz-container {
    background: rgba(255, 255, 255, 0.8) !important;
    backdrop-filter: blur(10px) !important;
    border-radius: 16px !important;
    padding: var(--space-xl) !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
}

.quiz-header {
    display: flex !important;
    justify-content: space-between !important;
    align-items: center !important;
    margin-bottom: var(--space-xl) !important;
    padding-bottom: var(--space-md) !important;
    border-bottom: 2px solid rgba(0, 0, 0, 0.1) !important;
}

.quiz-progress {
    font-size: var(--font-size-lg) !important;
    font-weight: 600 !important;
    color: var(--text-primary) !important;
}

.quiz-score {
    font-size: var(--font-size-lg) !important;
    font-weight: 600 !important;
    color: var(--color-success-600) !important;
}

.quiz-content {
    text-align: center !important;
    margin-bottom: var(--space-xl) !important;
}

.question-display {
    margin-bottom: var(--space-xl) !important;
}

.quiz-question-text {
    font-size: var(--font-size-lg) !important;
    color: var(--text-secondary) !important;
    margin-bottom: var(--space-md) !important;
}

.quiz-character {
    font-size: clamp(3rem, 8vw, 5rem) !important;
    font-weight: 700 !important;
    color: var(--color-primary-600) !important;
    font-family: var(--font-chinese) !important;
    margin-bottom: var(--space-sm) !important;
}

.quiz-pinyin {
    font-size: var(--font-size-xl) !important;
    color: var(--color-accent-600) !important;
    font-weight: 500 !important;
}

.quiz-options {
    display: grid !important;
    gap: var(--space-md) !important;
    max-width: 600px !important;
    margin: 0 auto !important;
}

.quiz-actions {
    display: flex !important;
    gap: var(--space-md) !important;
    justify-content: center !important;
}

/* Enhanced quiz results */
.quiz-results {
    text-align: center !important;
    background: rgba(255, 255, 255, 0.8) !important;
    backdrop-filter: blur(10px) !important;
    border-radius: 16px !important;
    padding: var(--space-2xl) !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
}

.quiz-results h3 {
    font-size: var(--font-size-3xl) !important;
    font-weight: 700 !important;
    color: var(--color-success-600) !important;
    margin-bottom: var(--space-xl) !important;
}

.results-grid {
    display: grid !important;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)) !important;
    gap: var(--space-lg) !important;
    margin-bottom: var(--space-xl) !important;
}

.result-card {
    background: rgba(255, 255, 255, 0.6) !important;
    border-radius: 12px !important;
    padding: var(--space-lg) !important;
    backdrop-filter: blur(5px) !important;
    border: 1px solid rgba(255, 255, 255, 0.3) !important;
}

.result-label {
    font-size: var(--font-size-sm) !important;
    color: var(--text-secondary) !important;
    text-transform: uppercase !important;
    letter-spacing: 0.5px !important;
    font-weight: 500 !important;
    margin-bottom: var(--space-xs) !important;
}

.result-value {
    font-size: var(--font-size-2xl) !important;
    font-weight: 700 !important;
    color: var(--color-primary-600) !important;
}

/* Enhanced stats grid */
.stats-grid {
    display: grid !important;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)) !important;
    gap: var(--space-lg) !important;
    margin-bottom: var(--space-2xl) !important;
}

.stat-card {
    background: rgba(255, 255, 255, 0.8) !important;
    backdrop-filter: blur(10px) !important;
    border-radius: 16px !important;
    padding: var(--space-xl) !important;
    text-align: center !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
    transition: all 0.3s ease !important;
    position: relative !important;
    overflow: hidden !important;
}

.stat-card::before {
    content: '' !important;
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    height: 4px !important;
    background: linear-gradient(90deg, 
        var(--color-primary-500), 
        var(--color-accent-500)) !important;
}

.stat-card:hover {
    transform: translateY(-5px) !important;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.15) !important;
}

.stat-value {
    font-size: clamp(2rem, 4vw, 3rem) !important;
    font-weight: 700 !important;
    color: var(--color-primary-600) !important;
    margin-bottom: var(--space-sm) !important;
}

.stat-label {
    font-size: var(--font-size-sm) !important;
    color: var(--text-secondary) !important;
    text-transform: uppercase !important;
    letter-spacing: 0.5px !important;
    font-weight: 500 !important;
}

/* Enhanced level progress */
.level-progress {
    background: rgba(255, 255, 255, 0.8) !important;
    backdrop-filter: blur(10px) !important;
    border-radius: 16px !important;
    padding: var(--space-xl) !important;
    margin-bottom: var(--space-xl) !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1) !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
}

.level-progress h4 {
    font-size: var(--font-size-xl) !important;
    font-weight: 600 !important;
    color: var(--text-primary) !important;
    margin-bottom: var(--space-lg) !important;
    text-align: center !important;
}

/* Loading states */
.loading-overlay {
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    background: rgba(0, 0, 0, 0.5) !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    z-index: 10000 !important;
    backdrop-filter: blur(5px) !important;
}

.loading-spinner {
    width: 60px !important;
    height: 60px !important;
    border: 4px solid rgba(255, 255, 255, 0.3) !important;
    border-top: 4px solid var(--color-primary-500) !important;
    border-radius: 50% !important;
    animation: spin 1s linear infinite !important;
}

.loading-text {
    color: white !important;
    font-size: var(--font-size-lg) !important;
    font-weight: 500 !important;
    margin-top: var(--space-md) !important;
    text-align: center !important;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Error states */
.error-message {
    background: linear-gradient(135deg, 
        var(--color-error-50), 
        var(--color-error-100)) !important;
    border: 1px solid var(--color-error-300) !important;
    border-radius: 12px !important;
    padding: var(--space-lg) !important;
    margin: var(--space-md) 0 !important;
    color: var(--color-error-700) !important;
    display: flex !important;
    align-items: center !important;
    gap: var(--space-sm) !important;
}

.error-message::before {
    content: '⚠️' !important;
    font-size: var(--font-size-lg) !important;
}

/* Success states */
.success-message {
    background: linear-gradient(135deg, 
        var(--color-success-50), 
        var(--color-success-100)) !important;
    border: 1px solid var(--color-success-300) !important;
    border-radius: 12px !important;
    padding: var(--space-lg) !important;
    margin: var(--space-md) 0 !important;
    color: var(--color-success-700) !important;
    display: flex !important;
    align-items: center !important;
    gap: var(--space-sm) !important;
}

.success-message::before {
    content: '✅' !important;
    font-size: var(--font-size-lg) !important;
}

/* Responsive adjustments for body */
@media (max-width: 768px) {
    .welcome-stats {
        flex-direction: column !important;
        align-items: center !important;
    }
    
    .welcome-stat {
        width: 100% !important;
        max-width: 200px !important;
    }
    
    .search-container {
        flex-direction: column !important;
    }
    
    .search-input {
        min-width: 100% !important;
    }
    
    .quiz-options {
        grid-template-columns: 1fr !important;
    }
    
    .results-grid {
        grid-template-columns: 1fr !important;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr) !important;
    }
}

@media (max-width: 480px) {
    .welcome-message {
        padding: var(--space-xl) !important;
    }
    
    .stats-grid {
        grid-template-columns: 1fr !important;
    }
    
    .quiz-actions {
        flex-direction: column !important;
    }
    
    .quiz-header {
        flex-direction: column !important;
        gap: var(--space-sm) !important;
        text-align: center !important;
    }
}/* =====
==============================
   BROWSE SECTION INFINITE SCROLL STYLES
   =================================== */

/* Audio button for vocabulary cards */
.vocab-audio-btn {
    position: absolute !important;
    top: var(--space-sm) !important;
    right: var(--space-sm) !important;
    background: rgba(255, 255, 255, 0.9) !important;
    border: 1px solid var(--color-primary-300) !important;
    border-radius: 50% !important;
    width: 32px !important;
    height: 32px !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    cursor: pointer !important;
    font-size: 0.875rem !important;
    transition: all 0.3s ease !important;
    z-index: 2 !important;
}

.vocab-audio-btn:hover {
    background: var(--color-primary-500) !important;
    color: white !important;
    transform: scale(1.1) !important;
    box-shadow: 0 4px 12px rgba(225, 29, 72, 0.3) !important;
}

.vocab-card {
    position: relative !important;
}

/* Loading indicator */
.browse-loading {
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
    justify-content: center !important;
    padding: var(--space-xl) !important;
    margin: var(--space-lg) 0 !important;
    background: rgba(255, 255, 255, 0.8) !important;
    backdrop-filter: blur(10px) !important;
    border-radius: 12px !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1) !important;
}

.browse-loading .loading-spinner {
    width: 40px !important;
    height: 40px !important;
    border: 3px solid rgba(225, 29, 72, 0.2) !important;
    border-top: 3px solid var(--color-primary-500) !important;
    border-radius: 50% !important;
    animation: spin 1s linear infinite !important;
    margin-bottom: var(--space-md) !important;
}

.browse-loading .loading-text {
    color: var(--text-secondary) !important;
    font-size: var(--font-size-sm) !important;
    font-weight: 500 !important;
}

/* No more items indicator */
.browse-no-more {
    text-align: center !important;
    padding: var(--space-xl) !important;
    margin: var(--space-lg) 0 !important;
    background: rgba(16, 185, 129, 0.1) !important;
    border: 1px solid rgba(16, 185, 129, 0.2) !important;
    border-radius: 12px !important;
    color: var(--color-success-700) !important;
}

.no-more-text {
    font-size: var(--font-size-base) !important;
    font-weight: 600 !important;
}

/* No results message */
.no-results {
    grid-column: 1 / -1 !important;
    text-align: center !important;
    padding: var(--space-3xl) !important;
    background: rgba(255, 255, 255, 0.8) !important;
    backdrop-filter: blur(10px) !important;
    border-radius: 16px !important;
    border: 1px solid rgba(255, 255, 255, 0.2) !important;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1) !important;
}

.no-results-icon {
    font-size: 3rem !important;
    margin-bottom: var(--space-md) !important;
    opacity: 0.6 !important;
}

.no-results-text {
    font-size: var(--font-size-xl) !important;
    font-weight: 600 !important;
    color: var(--text-primary) !important;
    margin-bottom: var(--space-sm) !important;
}

.no-results-subtitle {
    font-size: var(--font-size-sm) !important;
    color: var(--text-secondary) !important;
}

/* Enhanced vocabulary grid for infinite scroll */
.vocabulary-grid {
    min-height: 400px !important;
}

/* Dark theme adjustments */
[data-theme="dark"] .vocab-audio-btn {
    background: rgba(15, 23, 42, 0.9) !important;
    border-color: rgba(71, 85, 105, 0.5) !important;
    color: white !important;
}

[data-theme="dark"] .vocab-audio-btn:hover {
    background: var(--color-primary-500) !important;
}

[data-theme="dark"] .browse-loading {
    background: rgba(15, 23, 42, 0.8) !important;
    border-color: rgba(71, 85, 105, 0.3) !important;
}

[data-theme="dark"] .browse-loading .loading-text {
    color: rgba(255, 255, 255, 0.8) !important;
}

[data-theme="dark"] .browse-no-more {
    background: rgba(16, 185, 129, 0.2) !important;
    border-color: rgba(16, 185, 129, 0.3) !important;
    color: var(--color-success-400) !important;
}

[data-theme="dark"] .no-results {
    background: rgba(15, 23, 42, 0.8) !important;
    border-color: rgba(71, 85, 105, 0.3) !important;
}

[data-theme="dark"] .no-results-text {
    color: white !important;
}

[data-theme="dark"] .no-results-subtitle {
    color: rgba(255, 255, 255, 0.7) !important;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .vocab-audio-btn {
        width: 28px !important;
        height: 28px !important;
        font-size: 0.75rem !important;
    }
    
    .browse-loading {
        padding: var(--space-lg) !important;
    }
    
    .browse-loading .loading-spinner {
        width: 32px !important;
        height: 32px !important;
    }
}

@media (max-width: 480px) {
    .no-results {
        padding: var(--space-xl) !important;
    }
    
    .no-results-icon {
        font-size: 2rem !important;
    }
    
    .no-results-text {
        font-size: var(--font-size-lg) !important;
    }
}/* ==
=================================
   QUIZ FEEDBACK AND UI IMPROVEMENTS
   =================================== */

/* Quiz feedback styles */
.quiz-feedback {
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
    justify-content: center !important;
    padding: var(--space-lg) !important;
    margin: var(--space-md) 0 !important;
    border-radius: 12px !important;
    animation: feedbackSlideIn 0.3s ease-out !important;
    transition: opacity 0.3s ease !important;
}

.quiz-feedback.correct {
    background: linear-gradient(135deg, 
        var(--color-success-50), 
        var(--color-success-100)) !important;
    border: 2px solid var(--color-success-300) !important;
    color: var(--color-success-700) !important;
}

.quiz-feedback.incorrect {
    background: linear-gradient(135deg, 
        var(--color-error-50), 
        var(--color-error-100)) !important;
    border: 2px solid var(--color-error-300) !important;
    color: var(--color-error-700) !important;
}

.feedback-icon {
    font-size: 2rem !important;
    margin-bottom: var(--space-sm) !important;
}

.feedback-text {
    font-size: var(--font-size-lg) !important;
    font-weight: 600 !important;
    margin-bottom: var(--space-xs) !important;
}

.feedback-answer {
    font-size: var(--font-size-sm) !important;
    opacity: 0.8 !important;
    font-weight: 500 !important;
}

/* Enhanced quiz option selection */
.quiz-option.selected {
    background: linear-gradient(135deg, 
        var(--color-primary-100), 
        var(--color-primary-200)) !important;
    border-color: var(--color-primary-500) !important;
    color: var(--color-primary-700) !important;
    box-shadow: 0 0 0 3px rgba(225, 29, 72, 0.2) !important;
    transform: scale(1.02) !important;
}

.quiz-option.selected::before {
    content: '✓' !important;
    position: absolute !important;
    right: var(--space-sm) !important;
    top: 50% !important;
    transform: translateY(-50%) !important;
    font-weight: bold !important;
    color: var(--color-primary-600) !important;
}

/* Enhanced submit button states */
.btn.ready {
    background: linear-gradient(135deg, 
        var(--color-success-500), 
        var(--color-success-600)) !important;
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.3) !important;
    animation: buttonPulse 2s ease-in-out infinite !important;
}

/* Quiz progress indicator */
.quiz-progress {
    position: relative !important;
}

.quiz-progress::after {
    content: '' !important;
    position: absolute !important;
    bottom: -4px !important;
    left: 0 !important;
    width: calc(var(--progress, 0) * 1%) !important;
    height: 3px !important;
    background: linear-gradient(90deg, 
        var(--color-primary-500), 
        var(--color-accent-500)) !important;
    border-radius: 2px !important;
    transition: width 0.5s ease !important;
}

/* Enhanced quiz character display */
.quiz-character {
    position: relative !important;
    display: inline-block !important;
}

.quiz-character::after {
    content: '' !important;
    position: absolute !important;
    bottom: -10px !important;
    left: 50% !important;
    transform: translateX(-50%) !important;
    width: 60% !important;
    height: 3px !important;
    background: linear-gradient(90deg, 
        var(--color-accent-400), 
        var(--color-accent-600)) !important;
    border-radius: 2px !important;
}

/* Quiz score highlight */
.quiz-score {
    position: relative !important;
}

.quiz-score span:last-child {
    font-weight: 700 !important;
    color: var(--color-success-600) !important;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.1) !important;
}

/* Animations */
@keyframes feedbackSlideIn {
    0% {
        opacity: 0;
        transform: translateY(-20px) scale(0.9);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@keyframes buttonPulse {
    0%, 100% {
        box-shadow: 0 4px 15px rgba(16, 185, 129, 0.3);
    }
    50% {
        box-shadow: 0 6px 20px rgba(16, 185, 129, 0.5);
    }
}

/* Dark theme adjustments */
[data-theme="dark"] .quiz-feedback.correct {
    background: linear-gradient(135deg, 
        rgba(16, 185, 129, 0.2), 
        rgba(16, 185, 129, 0.3)) !important;
    border-color: var(--color-success-400) !important;
    color: var(--color-success-300) !important;
}

[data-theme="dark"] .quiz-feedback.incorrect {
    background: linear-gradient(135deg, 
        rgba(239, 68, 68, 0.2), 
        rgba(239, 68, 68, 0.3)) !important;
    border-color: var(--color-error-400) !important;
    color: var(--color-error-300) !important;
}

[data-theme="dark"] .quiz-option.selected {
    background: linear-gradient(135deg, 
        rgba(225, 29, 72, 0.2), 
        rgba(225, 29, 72, 0.3)) !important;
    border-color: var(--color-primary-400) !important;
    color: var(--color-primary-300) !important;
}

[data-theme="dark"] .quiz-score span:last-child {
    color: var(--color-success-400) !important;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .quiz-feedback {
        padding: var(--space-md) !important;
        margin: var(--space-sm) 0 !important;
    }
    
    .feedback-icon {
        font-size: 1.5rem !important;
    }
    
    .feedback-text {
        font-size: var(--font-size-base) !important;
    }
    
    .quiz-option.selected::before {
        right: var(--space-xs) !important;
    }
}

@media (max-width: 480px) {
    .quiz-feedback {
        padding: var(--space-sm) !important;
    }
    
    .feedback-icon {
        font-size: 1.25rem !important;
    }
    
    .feedback-text {
        font-size: var(--font-size-sm) !important;
    }
}/*
 ===================================
   STANDARDIZED UI COMPONENTS
   =================================== */

/* Consistent focus states for all interactive elements */
button:focus,
.btn:focus,
input:focus,
select:focus,
.nav-tab:focus,
.quiz-option:focus,
.vocab-card:focus {
    outline: 2px solid var(--color-primary-500) !important;
    outline-offset: 2px !important;
    box-shadow: 0 0 0 4px rgba(225, 29, 72, 0.2) !important;
}

/* Consistent hover effects for all buttons */
button:hover:not(:disabled),
.btn:hover:not(:disabled),
.nav-tab:hover,
.quiz-option:hover:not(:disabled),
.vocab-audio-btn:hover {
    transform: translateY(-2px) !important;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15) !important;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1) !important;
}

/* Consistent disabled states */
button:disabled,
.btn:disabled,
input:disabled,
select:disabled {
    opacity: 0.6 !important;
    cursor: not-allowed !important;
    transform: none !important;
    box-shadow: none !important;
}

/* Loading states for buttons */
.btn.loading {
    position: relative !important;
    color: transparent !important;
    pointer-events: none !important;
}

.btn.loading::after {
    content: '' !important;
    position: absolute !important;
    top: 50% !important;
    left: 50% !important;
    transform: translate(-50%, -50%) !important;
    width: 16px !important;
    height: 16px !important;
    border: 2px solid rgba(255, 255, 255, 0.3) !important;
    border-top: 2px solid white !important;
    border-radius: 50% !important;
    animation: spin 1s linear infinite !important;
}

/* Consistent form input styling */
input[type="text"],
input[type="search"],
input[type="email"],
input[type="password"],
textarea,
select {
    padding: var(--space-md) !important;
    border: 2px solid var(--color-border) !important;
    border-radius: 8px !important;
    background: var(--color-surface) !important;
    color: var(--text-primary) !important;
    font-family: var(--font-primary) !important;
    font-size: var(--font-size-base) !important;
    transition: all 0.3s ease !important;
    width: 100% !important;
    box-sizing: border-box !important;
}

input[type="text"]:hover,
input[type="search"]:hover,
input[type="email"]:hover,
input[type="password"]:hover,
textarea:hover,
select:hover {
    border-color: var(--color-primary-300) !important;
    box-shadow: 0 0 0 3px rgba(225, 29, 72, 0.1) !important;
}

input[type="text"]:focus,
input[type="search"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
textarea:focus,
select:focus {
    border-color: var(--color-primary-500) !important;
    box-shadow: 0 0 0 3px rgba(225, 29, 72, 0.2) !important;
}

/* Placeholder styling */
input::placeholder,
textarea::placeholder {
    color: var(--text-tertiary) !important;
    opacity: 0.7 !important;
}

/* Consistent radio button styling */
input[type="radio"] {
    width: 18px !important;
    height: 18px !important;
    border: 2px solid var(--color-border) !important;
    border-radius: 50% !important;
    background: var(--color-surface) !important;
    cursor: pointer !important;
    position: relative !important;
    margin: 0 !important;
    appearance: none !important;
    -webkit-appearance: none !important;
    transition: all 0.3s ease !important;
}

input[type="radio"]:checked {
    border-color: var(--color-primary-500) !important;
    background: var(--color-primary-500) !important;
}

input[type="radio"]:checked::after {
    content: '' !important;
    position: absolute !important;
    top: 50% !important;
    left: 50% !important;
    transform: translate(-50%, -50%) !important;
    width: 6px !important;
    height: 6px !important;
    border-radius: 50% !important;
    background: white !important;
}

input[type="radio"]:hover {
    border-color: var(--color-primary-300) !important;
    box-shadow: 0 0 0 3px rgba(225, 29, 72, 0.1) !important;
}

/* Consistent checkbox styling */
input[type="checkbox"] {
    width: 18px !important;
    height: 18px !important;
    border: 2px solid var(--color-border) !important;
    border-radius: 4px !important;
    background: var(--color-surface) !important;
    cursor: pointer !important;
    position: relative !important;
    margin: 0 !important;
    appearance: none !important;
    -webkit-appearance: none !important;
    transition: all 0.3s ease !important;
}

input[type="checkbox"]:checked {
    border-color: var(--color-primary-500) !important;
    background: var(--color-primary-500) !important;
}

input[type="checkbox"]:checked::after {
    content: '✓' !important;
    position: absolute !important;
    top: 50% !important;
    left: 50% !important;
    transform: translate(-50%, -50%) !important;
    color: white !important;
    font-size: 12px !important;
    font-weight: bold !important;
}

input[type="checkbox"]:hover {
    border-color: var(--color-primary-300) !important;
    box-shadow: 0 0 0 3px rgba(225, 29, 72, 0.1) !important;
}

/* Consistent label styling */
label {
    font-weight: 500 !important;
    color: var(--text-primary) !important;
    cursor: pointer !important;
    user-select: none !important;
    transition: color 0.3s ease !important;
}

label:hover {
    color: var(--color-primary-600) !important;
}

/* Error and success states for forms */
.form-group.error input,
.form-group.error select,
.form-group.error textarea {
    border-color: var(--color-error-500) !important;
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1) !important;
}

.form-group.success input,
.form-group.success select,
.form-group.success textarea {
    border-color: var(--color-success-500) !important;
    box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.1) !important;
}

.form-error-message {
    color: var(--color-error-600) !important;
    font-size: var(--font-size-sm) !important;
    margin-top: var(--space-xs) !important;
    display: flex !important;
    align-items: center !important;
    gap: var(--space-xs) !important;
}

.form-error-message::before {
    content: '⚠️' !important;
}

.form-success-message {
    color: var(--color-success-600) !important;
    font-size: var(--font-size-sm) !important;
    margin-top: var(--space-xs) !important;
    display: flex !important;
    align-items: center !important;
    gap: var(--space-xs) !important;
}

.form-success-message::before {
    content: '✅' !important;
}

/* Consistent card hover effects */
.vocab-card,
.stat-card,
.result-card,
.welcome-stat {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1) !important;
}

.vocab-card:hover,
.stat-card:hover,
.result-card:hover,
.welcome-stat:hover {
    transform: translateY(-4px) scale(1.02) !important;
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.15) !important;
}

/* Consistent loading animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes slideInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes scaleIn {
    from { opacity: 0; transform: scale(0.9); }
    to { opacity: 1; transform: scale(1); }
}

/* Apply animations to new content */
.vocab-card {
    animation: fadeIn 0.4s ease-out !important;
}

.tab-panel.active {
    animation: slideInUp 0.5s ease-out !important;
}

.quiz-feedback {
    animation: scaleIn 0.3s ease-out !important;
}

/* Dark theme adjustments for forms */
[data-theme="dark"] input[type="text"],
[data-theme="dark"] input[type="search"],
[data-theme="dark"] input[type="email"],
[data-theme="dark"] input[type="password"],
[data-theme="dark"] textarea,
[data-theme="dark"] select {
    background: var(--color-secondary-800) !important;
    border-color: var(--color-secondary-600) !important;
    color: white !important;
}

[data-theme="dark"] input[type="radio"],
[data-theme="dark"] input[type="checkbox"] {
    background: var(--color-secondary-800) !important;
    border-color: var(--color-secondary-600) !important;
}

[data-theme="dark"] label {
    color: white !important;
}

[data-theme="dark"] input::placeholder,
[data-theme="dark"] textarea::placeholder {
    color: rgba(255, 255, 255, 0.5) !important;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    button:hover:not(:disabled),
    .btn:hover:not(:disabled),
    .nav-tab:hover,
    .quiz-option:hover:not(:disabled) {
        transform: none !important; /* Disable hover transforms on mobile */
    }
    
    input[type="text"],
    input[type="search"],
    input[type="email"],
    input[type="password"],
    textarea,
    select {
        font-size: 16px !important; /* Prevent zoom on iOS */
    }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    button:focus,
    .btn:focus,
    input:focus,
    select:focus {
        outline: 3px solid currentColor !important;
        outline-offset: 2px !important;
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    button:hover:not(:disabled),
    .btn:hover:not(:disabled) {
        transform: none !important;
    }
}