/* Import Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&family=Poppins:wght@400;500;600;700;800;900&display=swap');

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Dark Mode - Futuristic Color Palette */
    --bg-primary: #121212;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #2a2a2a;
    --bg-card: #1e1e1e;
    --bg-glass: rgba(30, 30, 30, 0.8);
    
    /* Neon Accent Colors */
    --neon-green: #4ADE80;
    --neon-blue: #60A5FA;
    --neon-purple: #A78BFA;
    --neon-pink: #F472B6;
    --neon-orange: #FB923C;
    
    /* Text Colors */
    --text-primary: #ffffff;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;
    --text-accent: #4ADE80;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #4ADE80, #60A5FA);
    --gradient-secondary: linear-gradient(135deg, #A78BFA, #F472B6);
    --gradient-accent: linear-gradient(135deg, #60A5FA, #A78BFA);
    --gradient-glow: linear-gradient(135deg, #4ADE80, #60A5FA, #A78BFA);
    
    /* Shadows and Effects */
    --shadow-neon: 0 0 20px rgba(74, 222, 128, 0.3);
    --shadow-neon-blue: 0 0 20px rgba(96, 165, 250, 0.3);
    --shadow-neon-purple: 0 0 20px rgba(167, 139, 250, 0.3);
    --shadow-glow: 0 0 30px rgba(74, 222, 128, 0.4);
    --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
    --shadow-floating: 0 20px 40px rgba(0, 0, 0, 0.6);
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 50px;
    
    /* Transitions */
    --transition-fast: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

[data-theme="light"] {
    /* Light Mode - Minimal Clean Palette */
    --bg-primary: #F9FAFB;
    --bg-secondary: #F3F4F6;
    --bg-tertiary: #E5E7EB;
    --bg-card: #FFFFFF;
    --bg-glass: rgba(255, 255, 255, 0.9);
    
    /* Light Mode Accent Colors */
    --neon-green: #22C55E;
    --neon-blue: #3B82F6;
    --neon-purple: #8B5CF6;
    --neon-pink: #EC4899;
    --neon-orange: #F97316;
    
    /* Light Mode Text Colors */
    --text-primary: #111827;
    --text-secondary: #6B7280;
    --text-muted: #9CA3AF;
    --text-accent: #3B82F6;
    
    /* Light Mode Gradients */
    --gradient-primary: linear-gradient(135deg, #3B82F6, #22C55E);
    --gradient-secondary: linear-gradient(135deg, #8B5CF6, #EC4899);
    --gradient-accent: linear-gradient(135deg, #3B82F6, #8B5CF6);
    --gradient-glow: linear-gradient(135deg, #3B82F6, #22C55E, #8B5CF6);
    
    /* Light Mode Shadows and Effects */
    --shadow-neon: 0 0 20px rgba(59, 130, 246, 0.2);
    --shadow-neon-blue: 0 0 20px rgba(59, 130, 246, 0.2);
    --shadow-neon-purple: 0 0 20px rgba(139, 92, 246, 0.2);
    --shadow-glow: 0 0 30px rgba(59, 130, 246, 0.3);
    --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-floating: 0 10px 30px rgba(0, 0, 0, 0.12);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: var(--transition-smooth);
}

/* Dark mode background gradients */
body:not([data-theme="light"]) {
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(74, 222, 128, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(96, 165, 250, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(167, 139, 250, 0.1) 0%, transparent 50%);
}

/* Light mode background gradients */
body[data-theme="light"] {
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(59, 130, 246, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(34, 197, 94, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(139, 92, 246, 0.05) 0%, transparent 50%);
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.screen {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Neon Glow Effects */
.neon-glow {
    box-shadow: var(--shadow-neon);
    transition: var(--transition-smooth);
}

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

.neon-border {
    border: 2px solid transparent;
    background: linear-gradient(var(--bg-card), var(--bg-card)) padding-box,
                var(--gradient-primary) border-box;
    border-radius: var(--radius-md);
}

/* Light Mode Specific Adjustments */
[data-theme="light"] .neon-glow {
    box-shadow: 0 0 0 1px rgba(59, 130, 246, 0.2), var(--shadow-card);
}

[data-theme="light"] .neon-glow:hover {
    box-shadow: 0 0 0 1px rgba(59, 130, 246, 0.4), var(--shadow-floating);
}

[data-theme="light"] .neon-border {
    border: 2px solid rgba(59, 130, 246, 0.2);
    background: var(--bg-card);
}

[data-theme="light"] .neon-border:hover {
    border-color: rgba(59, 130, 246, 0.4);
    box-shadow: var(--shadow-card);
}

/* Loading Screen */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    background-image: 
        radial-gradient(circle at 50% 50%, rgba(74, 222, 128, 0.2) 0%, transparent 70%);
}

.loading-content {
    text-align: center;
    color: var(--text-primary);
}

.app-icon {
    width: 4rem;
    height: 4rem;
    margin-bottom: 1rem;
    color: var(--neon-green);
    filter: drop-shadow(0 0 20px rgba(74, 222, 128, 0.5));
    animation: pulse 2s ease-in-out infinite;
}

.app-icon svg {
    width: 100%;
    height: 100%;
}

.loading-content h1 {
    font-size: 2.5rem;
    font-weight: 900;
    margin-bottom: 2rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 3px solid rgba(74, 222, 128, 0.2);
    border-top: 3px solid var(--neon-green);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto;
    box-shadow: var(--shadow-neon);
}

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

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

/* Authentication Screen */
.auth-container {
    max-width: 400px;
    margin: 0 auto;
    padding: 2rem 1rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.auth-header {
    text-align: center;
    margin-bottom: 3rem;
}

.auth-header .app-icon {
    width: 3.5rem;
    height: 3.5rem;
    margin-bottom: 1rem;
}

.auth-header h1 {
    font-size: 2.5rem;
    font-weight: 900;
    margin-bottom: 0.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.auth-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 500;
}

.auth-options {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.auth-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    padding: 1.2rem;
    border: none;
    border-radius: var(--radius-lg);
    background: var(--bg-card);
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth);
    width: 100%;
    position: relative;
    overflow: hidden;
}

.auth-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    transition: var(--transition-smooth);
}

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

.auth-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-card);
}

.google-btn {
    background: linear-gradient(135deg, #4285f4, #34a853);
    box-shadow: 0 0 20px rgba(66, 133, 244, 0.3);
}

.email-btn {
    background: var(--gradient-primary);
    box-shadow: var(--shadow-neon);
}

.phone-btn {
    background: var(--gradient-secondary);
    box-shadow: var(--shadow-neon-purple);
}

.auth-icon {
    font-size: 1.25rem;
}

.auth-form {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    padding: 2rem;
    border-radius: var(--radius-xl);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
}

.auth-form h3 {
    margin-bottom: 1.5rem;
    text-align: center;
    color: var(--text-primary);
    font-weight: 700;
    font-size: 1.5rem;
}

.auth-form input {
    width: 100%;
    padding: 1rem 1.2rem;
    border: 2px solid rgba(74, 222, 128, 0.2);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 1rem;
    transition: var(--transition-smooth);
}

.auth-form input:focus {
    outline: none;
    border-color: var(--neon-green);
    box-shadow: var(--shadow-neon);
    background: var(--bg-tertiary);
}

.primary-btn {
    background: var(--gradient-primary);
    color: white;
    border: none;
    margin-bottom: 0.5rem;
    box-shadow: var(--shadow-neon);
}

.secondary-btn {
    background: transparent;
    color: var(--neon-green);
    border: 2px solid var(--neon-green);
    margin-bottom: 1rem;
}

.secondary-btn:hover {
    background: var(--neon-green);
    color: var(--bg-primary);
    box-shadow: var(--shadow-neon);
}

.back-btn {
    background: transparent;
    color: var(--text-secondary);
    border: none;
    padding: 0.5rem;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition-fast);
}

.back-btn:hover {
    color: var(--text-primary);
}

/* App Header */
.app-header {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(74, 222, 128, 0.1);
    padding: 1rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 100%;
}

.header-content h1 {
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.header-actions {
    display: flex;
    gap: 0.5rem;
}

.icon-btn {
    width: 44px;
    height: 44px;
    border: none;
    background: var(--bg-card);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-smooth);
    font-size: 1.2rem;
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.icon-btn:hover {
    background: var(--bg-tertiary);
    transform: scale(1.05);
    box-shadow: var(--shadow-neon);
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 1.5rem;
    padding-bottom: 120px;
    max-width: 100%;
    overflow-x: hidden;
}

.content-screen {
    max-width: 100%;
}

/* Home Screen */
.welcome-section {
    text-align: center;
    margin-bottom: 2rem;
    padding: 2rem;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
    position: relative;
    overflow: hidden;
}

.welcome-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0.1;
    z-index: -1;
}

.welcome-section h2 {
    font-size: 1.8rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-section p {
    opacity: 0.9;
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.quick-actions {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    margin-bottom: 2rem;
}

.quick-action-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
    padding: 2rem 1.5rem;
    background: var(--bg-card);
    border: 1px solid rgba(74, 222, 128, 0.2);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition-smooth);
    text-decoration: none;
    color: var(--text-primary);
    position: relative;
    overflow: hidden;
}

.quick-action-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition-smooth);
    z-index: -1;
}

.quick-action-btn:hover::before {
    opacity: 0.1;
}

.quick-action-btn:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-floating);
    border-color: var(--neon-green);
}

.action-icon {
    width: 2.5rem;
    height: 2.5rem;
    color: var(--neon-green);
    filter: drop-shadow(0 0 10px rgba(74, 222, 128, 0.5));
}

.quick-action-btn span:last-child {
    font-weight: 600;
    font-size: 1rem;
    letter-spacing: -0.01em;
}

.stats-section, .recent-section {
    margin-bottom: 2rem;
}

.stats-section h3, .recent-section h3 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-size: 1.4rem;
    font-weight: 700;
    letter-spacing: -0.01em;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

.stat-card {
    background: var(--bg-card);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    text-align: center;
    border: 1px solid rgba(74, 222, 128, 0.2);
    transition: var(--transition-smooth);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition-smooth);
    z-index: -1;
}

.stat-card:hover::before {
    opacity: 0.05;
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-card);
    border-color: var(--neon-green);
}

.stat-number {
    display: block;
    font-size: 1.8rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
}

.activity-list {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    overflow: hidden;
    box-shadow: var(--shadow-card);
}

.activity-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.2rem;
    border-bottom: 1px solid rgba(74, 222, 128, 0.1);
    transition: var(--transition-fast);
}

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

.activity-item:hover {
    background: var(--bg-tertiary);
}

.activity-icon {
    width: 1.5rem;
    height: 1.5rem;
    color: var(--neon-green);
    filter: drop-shadow(0 0 8px rgba(74, 222, 128, 0.4));
}

.activity-text {
    color: var(--text-secondary);
    font-weight: 500;
}

/* Calendar */
.calendar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.calendar-header h2 {
    font-size: 1.4rem;
    color: var(--text-primary);
    font-weight: 700;
    letter-spacing: -0.01em;
}

.nav-btn {
    width: 44px;
    height: 44px;
    border: none;
    background: var(--bg-card);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-smooth);
    font-size: 1.2rem;
    color: var(--text-primary);
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.nav-btn:hover {
    background: var(--bg-tertiary);
    box-shadow: var(--shadow-neon);
    transform: scale(1.05);
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 1px;
    background: rgba(74, 222, 128, 0.2);
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow-card);
}

.calendar-day {
    background: var(--bg-card);
    padding: 0.75rem 0.5rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition-smooth);
    min-height: 60px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    font-weight: 600;
}

.calendar-day:hover {
    background: var(--bg-tertiary);
    box-shadow: var(--shadow-neon);
}

.calendar-day.other-month {
    color: var(--text-muted);
    background: var(--bg-secondary);
}

.calendar-day.today {
    background: var(--gradient-primary);
    color: var(--bg-primary);
    box-shadow: var(--shadow-neon);
}

.calendar-day.has-event {
    background: var(--gradient-secondary);
    color: var(--bg-primary);
    box-shadow: var(--shadow-neon-purple);
}

.calendar-day-header {
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    font-weight: 700;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Flashcards, Notes, Quizzes, Subjects and Groups */
.flashcards-header, .notes-header, .quizzes-header, .subjects-header, .groups-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.flashcards-header h2, .notes-header h2, .quizzes-header h2, .subjects-header h2, .groups-header h2 {
    font-size: 1.6rem;
    color: var(--text-primary);
    font-weight: 800;
    letter-spacing: -0.01em;
}

/* Light Mode Card Enhancements */
[data-theme="light"] .flashcard-item,
[data-theme="light"] .note-item,
[data-theme="light"] .quiz-item,
[data-theme="light"] .subject-item,
[data-theme="light"] .group-item {
    border: 1px solid rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow-card);
}

[data-theme="light"] .flashcard-item:hover,
[data-theme="light"] .note-item:hover,
[data-theme="light"] .quiz-item:hover,
[data-theme="light"] .subject-item:hover,
[data-theme="light"] .group-item:hover {
    border-color: rgba(59, 130, 246, 0.3);
    box-shadow: var(--shadow-floating);
}

[data-theme="light"] .stat-card {
    border: 1px solid rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow-card);
}

[data-theme="light"] .stat-card:hover {
    border-color: rgba(59, 130, 246, 0.3);
    box-shadow: var(--shadow-floating);
}

.action-btn {
    background: var(--gradient-primary);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-full);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth);
    box-shadow: var(--shadow-neon);
    font-size: 0.9rem;
}

.action-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

.flashcards-list, .notes-list, .quizzes-list, .subjects-list, .groups-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.flashcard-item, .note-item, .quiz-item, .subject-item, .group-item {
    background: var(--bg-card);
    border: 1px solid rgba(74, 222, 128, 0.2);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    cursor: pointer;
    transition: var(--transition-smooth);
    position: relative;
    overflow: hidden;
}

.flashcard-item::before, .note-item::before, .quiz-item::before, .subject-item::before, .group-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition-smooth);
    z-index: -1;
}

.flashcard-item:hover::before, .note-item:hover::before, .quiz-item:hover::before, .subject-item:hover::before, .group-item:hover::before {
    opacity: 0.05;
}

.flashcard-item:hover, .note-item:hover, .quiz-item:hover, .subject-item:hover, .group-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-floating);
    border-color: var(--neon-green);
}

.item-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.75rem;
}

.item-title {
    font-weight: 700;
    color: var(--text-primary);
    font-size: 1.2rem;
    letter-spacing: -0.01em;
}

.item-actions {
    display: flex;
    gap: 0.5rem;
}

.item-action-btn {
    width: 36px;
    height: 36px;
    border: none;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-smooth);
    font-size: 1rem;
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.item-action-btn:hover {
    background: var(--neon-green);
    color: var(--bg-primary);
    box-shadow: var(--shadow-neon);
    transform: scale(1.1);
}

.item-meta {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0.75rem;
    font-weight: 500;
}

.item-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
    font-weight: 500;
}

/* Profile */
.profile-header {
    text-align: center;
    margin-bottom: 2rem;
    padding: 2rem;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
}

.profile-avatar {
    width: 100px;
    height: 100px;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 3rem;
    line-height: 1;
    box-shadow: var(--shadow-neon);
    border: 3px solid var(--bg-primary);
}

.profile-header h2 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-weight: 800;
    font-size: 1.8rem;
    letter-spacing: -0.01em;
}

.profile-header p {
    color: var(--text-secondary);
    font-weight: 500;
}

.profile-actions {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.profile-btn {
    padding: 1.2rem;
    border: 1px solid rgba(74, 222, 128, 0.2);
    background: var(--bg-card);
    color: var(--text-primary);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition-smooth);
    font-weight: 600;
    font-size: 1rem;
}

.profile-btn:hover {
    background: var(--bg-tertiary);
    border-color: var(--neon-green);
    box-shadow: var(--shadow-neon);
    transform: translateY(-2px);
}

.logout-btn {
    background: linear-gradient(135deg, #ef4444, #dc2626);
    color: white;
    border-color: #ef4444;
    box-shadow: 0 0 20px rgba(239, 68, 68, 0.3);
}

.logout-btn:hover {
    background: linear-gradient(135deg, #dc2626, #b91c1c);
    box-shadow: 0 0 30px rgba(239, 68, 68, 0.4);
}

/* Bottom Navigation */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-top: 1px solid rgba(74, 222, 128, 0.2);
    display: flex;
    padding: 0.5rem 0;
    z-index: 100;
    overflow-x: auto;
    scrollbar-width: none;
    -ms-overflow-style: none;
}

.bottom-nav::-webkit-scrollbar {
    display: none;
}

.nav-item {
    flex: 1;
    min-width: 60px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.2rem;
    padding: 0.5rem 0.25rem;
    border: none;
    background: transparent;
    cursor: pointer;
    transition: var(--transition-smooth);
    color: var(--text-muted);
    border-radius: var(--radius-md);
    margin: 0 0.1rem;
}

.nav-item.active {
    color: var(--neon-green);
    background: rgba(74, 222, 128, 0.1);
    box-shadow: var(--shadow-neon);
}

.nav-item:hover {
    color: var(--neon-green);
    background: rgba(74, 222, 128, 0.05);
    transform: translateY(-2px);
}

.nav-icon {
    width: 1.2rem;
    height: 1.2rem;
    color: var(--text-secondary);
    filter: drop-shadow(0 0 8px rgba(74, 222, 128, 0.3));
}

.nav-label {
    font-size: 0.6rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.3px;
    text-align: center;
    line-height: 1.1;
}

/* Modals */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(18, 18, 18, 0.8);
    backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 1rem;
}

.modal-content {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    max-width: 500px;
    width: 100%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--shadow-floating);
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(18, 18, 18, 0.8);
    backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 1rem;
}

/* Pomodoro Timer */
.pomodoro-container {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    padding: 2.5rem;
    text-align: center;
    max-width: 400px;
    width: 100%;
    box-shadow: var(--shadow-floating);
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.pomodoro-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.pomodoro-header h2 {
    color: var(--text-primary);
    font-weight: 800;
    font-size: 1.5rem;
    letter-spacing: -0.01em;
}

.close-btn {
    width: 36px;
    height: 36px;
    border: none;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.2rem;
    color: var(--text-secondary);
    transition: var(--transition-smooth);
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.close-btn:hover {
    background: var(--neon-green);
    color: var(--bg-primary);
    box-shadow: var(--shadow-neon);
}

.timer-circle {
    width: 220px;
    height: 220px;
    border: 4px solid rgba(74, 222, 128, 0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 2rem;
    background: var(--bg-card);
    position: relative;
    box-shadow: var(--shadow-card);
}

.timer-circle::before {
    content: '';
    position: absolute;
    top: -4px;
    left: -4px;
    right: -4px;
    bottom: -4px;
    border: 4px solid transparent;
    border-top: 4px solid var(--neon-green);
    border-radius: 50%;
    transform: rotate(-90deg);
    transition: transform 0.3s ease;
    box-shadow: var(--shadow-neon);
}

#timer-display {
    font-size: 2.8rem;
    font-weight: 800;
    color: var(--text-primary);
    font-family: 'Inter', monospace;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.timer-controls {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.timer-controls button {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius-full);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth);
    font-size: 0.9rem;
}

#timer-start {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-neon);
}

#timer-pause {
    background: linear-gradient(135deg, #f59e0b, #d97706);
    color: white;
    box-shadow: 0 0 20px rgba(245, 158, 11, 0.3);
}

#timer-reset {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.timer-controls button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

.pomodoro-session-info p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

/* Flashcard Modal Styles */
.flashcard-modal {
    padding: 2rem;
}

.flashcard-content {
    margin-bottom: 2rem;
}

.flashcard-front, .flashcard-back {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
    transition: var(--transition-smooth);
}

.flashcard-front h3, .flashcard-back h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    line-height: 1.4;
}

.flashcard-actions {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.difficulty-buttons {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
}

.difficulty-btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius-full);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth);
    font-size: 0.9rem;
}

.difficulty-btn.easy {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-neon);
}

.difficulty-btn.medium {
    background: linear-gradient(135deg, #f59e0b, #d97706);
    color: white;
    box-shadow: 0 0 20px rgba(245, 158, 11, 0.3);
}

.difficulty-btn.hard {
    background: linear-gradient(135deg, #ef4444, #dc2626);
    color: white;
    box-shadow: 0 0 20px rgba(239, 68, 68, 0.3);
}

.difficulty-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

/* Quiz Modal Styles */
.quiz-modal {
    padding: 2rem;
}

.quiz-header {
    text-align: center;
    margin-bottom: 2rem;
}

.quiz-header h3 {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.quiz-header p {
    color: var(--text-secondary);
    font-weight: 500;
}

.quiz-question {
    margin-bottom: 2rem;
}

.quiz-question h4 {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    line-height: 1.4;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.quiz-option {
    padding: 1rem 1.5rem;
    border: 2px solid rgba(74, 222, 128, 0.2);
    background: var(--bg-card);
    color: var(--text-primary);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition-smooth);
    font-weight: 600;
    text-align: left;
    font-size: 1rem;
}

.quiz-option:hover {
    border-color: var(--neon-green);
    background: var(--bg-tertiary);
    box-shadow: var(--shadow-neon);
    transform: translateY(-2px);
}

/* Group Modal Styles */
.group-modal {
    padding: 2rem;
    max-width: 600px;
    width: 100%;
}

.group-header {
    text-align: center;
    margin-bottom: 1.5rem;
}

.group-header h3 {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.group-meta {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
}

.group-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid rgba(74, 222, 128, 0.2);
}

.tab-btn {
    padding: 0.75rem 1rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth);
    border-bottom: 2px solid transparent;
}

.tab-btn.active {
    color: var(--neon-green);
    border-bottom-color: var(--neon-green);
}

.tab-btn:hover {
    color: var(--neon-green);
}

.group-overview {
    text-align: center;
}

.group-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.stat-item {
    background: var(--bg-card);
    padding: 1rem;
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
}

.stat-item .stat-number {
    display: block;
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.25rem;
}

.stat-item .stat-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
}

.group-description {
    margin-bottom: 1.5rem;
    text-align: left;
}

.group-description h4 {
    color: var(--text-primary);
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.group-description p {
    color: var(--text-secondary);
    line-height: 1.6;
}

.group-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.group-calendar {
    text-align: center;
}

.group-events {
    margin-top: 1.5rem;
    text-align: left;
}

.group-events h4 {
    color: var(--text-primary);
    font-weight: 700;
    margin-bottom: 1rem;
}

.group-event {
    background: var(--bg-card);
    padding: 1rem;
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
    margin-bottom: 0.75rem;
}

.event-date {
    font-size: 0.8rem;
    color: var(--neon-green);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.25rem;
}

.event-title {
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.event-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.no-events {
    color: var(--text-muted);
    font-style: italic;
    text-align: center;
    padding: 2rem;
}

.group-content-tab {
    text-align: left;
}

.content-section {
    background: var(--bg-card);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
    margin-bottom: 1rem;
}

.content-section h4 {
    color: var(--text-primary);
    font-weight: 700;
    margin-bottom: 1rem;
}

.group-members {
    text-align: left;
}

.members-list {
    margin-bottom: 1.5rem;
}

.member-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
    margin-bottom: 0.75rem;
}

.member-avatar {
    font-size: 1.5rem;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 1;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.member-name {
    flex: 1;
    font-weight: 600;
    color: var(--text-primary);
}

.admin-badge {
    background: var(--gradient-primary);
    color: var(--bg-primary);
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-full);
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.member-actions {
    text-align: center;
}

.member-status {
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-full);
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.member-status.online {
    background: rgba(34, 197, 94, 0.2);
    color: #22C55E;
}

.member-status.offline {
    background: rgba(107, 114, 128, 0.2);
    color: #6B7280;
}

.member-status.studying {
    background: rgba(59, 130, 246, 0.2);
    color: #3B82F6;
}

.member-status.away {
    background: rgba(245, 158, 11, 0.2);
    color: #F59E0B;
}

/* Group Chat Styles */
.group-chat {
    display: flex;
    flex-direction: column;
    height: 400px;
    border: 1px solid rgba(74, 222, 128, 0.2);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.chat-messages {
    flex: 1;
    padding: 1rem;
    overflow-y: auto;
    background: var(--bg-tertiary);
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.chat-message {
    display: flex;
    gap: 0.75rem;
    align-items: flex-start;
}

.chat-message.own-message {
    flex-direction: row-reverse;
}

.chat-message.own-message .message-content {
    background: var(--gradient-primary);
    color: var(--bg-primary);
}

.message-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    line-height: 1;
    background: var(--bg-card);
    border: 1px solid rgba(74, 222, 128, 0.2);
    flex-shrink: 0;
}

.message-content {
    background: var(--bg-card);
    padding: 0.75rem 1rem;
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    max-width: 70%;
    box-shadow: var(--shadow-card);
}

.message-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.25rem;
}

.message-sender {
    font-weight: 600;
    font-size: 0.8rem;
    color: var(--text-primary);
}

.message-time {
    font-size: 0.7rem;
    color: var(--text-secondary);
}

.message-text {
    color: var(--text-primary);
    line-height: 1.4;
    word-wrap: break-word;
}

.chat-input {
    display: flex;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--bg-card);
    border-top: 1px solid rgba(74, 222, 128, 0.2);
}

.chat-input input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 1px solid rgba(74, 222, 128, 0.2);
    border-radius: var(--radius-md);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: 0.9rem;
}

.chat-input input:focus {
    outline: none;
    border-color: var(--neon-green);
    box-shadow: var(--shadow-neon);
}

.chat-input .action-btn {
    padding: 0.75rem 1.5rem;
    font-size: 0.9rem;
}

.no-messages {
    text-align: center;
    color: var(--text-muted);
    font-style: italic;
    padding: 2rem;
}

/* Activity Feed Styles */
.activity-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    margin-bottom: 0.5rem;
    font-size: 0.8rem;
}

.activity-user {
    font-weight: 600;
    color: var(--neon-green);
}

.activity-action {
    color: var(--text-secondary);
}

.activity-time {
    color: var(--text-muted);
    font-size: 0.7rem;
    margin-left: auto;
}

/* Profile Modal Styles */
.profile-modal {
    padding: 2rem;
    max-width: 500px;
    width: 100%;
}

.profile-header {
    text-align: center;
    margin-bottom: 1.5rem;
}

.profile-header h3 {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.profile-form {
    text-align: left;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    color: var(--text-primary);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.form-group input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid rgba(74, 222, 128, 0.2);
    border-radius: var(--radius-md);
    background: var(--bg-card);
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 500;
    transition: var(--transition-smooth);
}

.form-group input:focus {
    outline: none;
    border-color: var(--neon-green);
    box-shadow: var(--shadow-neon);
}

.avatar-grid {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    gap: 0.5rem;
    margin-top: 0.5rem;
}

.avatar-option {
    width: 50px;
    height: 50px;
    border: 2px solid rgba(74, 222, 128, 0.2);
    background: var(--bg-card);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-smooth);
    font-size: 1.8rem;
    line-height: 1;
}

.avatar-option:hover {
    border-color: var(--neon-green);
    box-shadow: var(--shadow-neon);
    transform: scale(1.05);
}

.avatar-option.selected {
    border-color: var(--neon-green);
    background: rgba(74, 222, 128, 0.1);
    box-shadow: var(--shadow-neon);
}

.form-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-top: 2rem;
}

.action-btn.secondary {
    background: transparent;
    color: var(--text-secondary);
    border: 2px solid rgba(74, 222, 128, 0.2);
}

.action-btn.secondary:hover {
    background: var(--bg-tertiary);
    border-color: var(--neon-green);
    color: var(--text-primary);
}

/* Subject Item Styles */
.subject-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.subject-icon {
    width: 2rem;
    height: 2rem;
    color: var(--neon-green);
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-tertiary);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.subject-info {
    flex: 1;
}

.subject-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.subject-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.4;
}

.subject-stats {
    display: flex;
    gap: 1rem;
    justify-content: space-around;
    padding-top: 1rem;
    border-top: 1px solid rgba(74, 222, 128, 0.1);
}

.subject-stat {
    text-align: center;
}

.subject-stat .stat-number {
    display: block;
    font-size: 1.2rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.25rem;
}

.subject-stat .stat-label {
    font-size: 0.7rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
}

/* Subject Modal Styles */
.subject-modal {
    padding: 2rem;
    max-width: 700px;
    width: 100%;
}

.subject-modal .subject-header {
    text-align: center;
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid rgba(74, 222, 128, 0.2);
}

.subject-icon-large {
    width: 3rem;
    height: 3rem;
    color: var(--neon-green);
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-tertiary);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    margin: 0 auto 1rem;
}

.subject-modal .subject-info h3 {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subject-modal .subject-description {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.5;
}

.subject-content {
    text-align: left;
}

.content-list {
    margin-bottom: 1rem;
}

.content-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    margin-bottom: 0.5rem;
    cursor: pointer;
    transition: var(--transition-smooth);
    border: 1px solid rgba(74, 222, 128, 0.1);
}

.content-item:hover {
    background: var(--bg-card);
    border-color: rgba(74, 222, 128, 0.3);
    transform: translateX(4px);
}

.content-icon {
    width: 1.2rem;
    height: 1.2rem;
    color: var(--neon-green);
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-card);
    border-radius: var(--radius-sm);
    border: 1px solid rgba(74, 222, 128, 0.2);
}

.content-title {
    flex: 1;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.no-content {
    color: var(--text-muted);
    font-style: italic;
    text-align: center;
    padding: 1rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    border: 1px solid rgba(74, 222, 128, 0.1);
}

.more-content {
    color: var(--neon-green);
    font-weight: 600;
    text-align: center;
    font-size: 0.8rem;
    margin-top: 0.5rem;
}

/* Note Modal Styles */
.note-modal {
    padding: 2rem;
}

.note-header {
    margin-bottom: 1.5rem;
    text-align: center;
}

.note-header h3 {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.note-meta {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
}

.note-content {
    background: var(--bg-card);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.note-content p {
    color: var(--text-primary);
    font-size: 1rem;
    margin: 0;
}

.note-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* Quiz Results */
.quiz-results {
    padding: 2rem;
    text-align: center;
}

.results-header h3 {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 1rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.score-display {
    margin-bottom: 2rem;
}

.score-number {
    display: block;
    font-size: 3rem;
    font-weight: 900;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

.score-percentage {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--neon-green);
}

.results-details p {
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: 1rem;
}

.results-details .success {
    color: var(--neon-green);
    font-weight: 700;
}

.results-details .warning {
    color: #f59e0b;
    font-weight: 700;
}

.results-details .error {
    color: #ef4444;
    font-weight: 700;
}

.results-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-top: 2rem;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem 2rem;
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(74, 222, 128, 0.2);
    box-shadow: var(--shadow-card);
}

.empty-icon {
    width: 4rem;
    height: 4rem;
    margin-bottom: 1.5rem;
    color: var(--neon-green);
    filter: drop-shadow(0 0 20px rgba(74, 222, 128, 0.3));
}

.empty-state h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.empty-state p {
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: 2rem;
}

/* Responsive Design */
@media (max-width: 480px) {
    .main-content {
        padding: 1rem;
        padding-bottom: 100px;
    }
    
    .quick-actions {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }
    
    .quick-action-btn {
        padding: 1.5rem 1rem;
    }
    
    .action-icon {
        width: 2rem;
        height: 2rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }
    
    .stat-card {
        padding: 1rem;
    }
    
    .calendar-day {
        min-height: 45px;
        padding: 0.4rem 0.2rem;
        font-size: 0.8rem;
    }
    
    .timer-circle {
        width: 160px;
        height: 160px;
    }
    
    #timer-display {
        font-size: 2rem;
    }
    
    .welcome-section {
        padding: 1.5rem;
    }
    
    .welcome-section h2 {
        font-size: 1.5rem;
    }
    
    .pomodoro-container {
        padding: 1.5rem;
    }
    
    .bottom-nav {
        padding: 0.4rem 0;
    }
    
    .nav-item {
        min-width: 50px;
        padding: 0.4rem 0.2rem;
    }
    
    .nav-icon {
        width: 1.1rem;
        height: 1.1rem;
    }
    
    .nav-label {
        font-size: 0.55rem;
    }
    
    .flashcards-header, .notes-header, .quizzes-header, .groups-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .flashcards-header h2, .notes-header h2, .quizzes-header h2, .groups-header h2 {
        font-size: 1.4rem;
    }
    
    .flashcard-item, .note-item, .quiz-item, .group-item {
        padding: 1rem;
    }
    
    .item-title {
        font-size: 1.1rem;
    }
    
    .header-content h1 {
        font-size: 1.3rem;
    }
    
    .icon-btn {
        width: 40px;
        height: 40px;
        font-size: 1.1rem;
    }
    
    .group-modal {
        padding: 1rem;
        max-width: 100%;
    }
    
    .group-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }
    
    .group-tabs {
        flex-wrap: wrap;
        gap: 0.25rem;
    }
    
    .tab-btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.8rem;
    }
    
    .avatar-grid {
        grid-template-columns: repeat(6, 1fr);
        gap: 0.25rem;
    }
    
    .avatar-option {
        width: 40px;
        height: 40px;
        font-size: 1.4rem;
    }
    
    .profile-modal {
        padding: 1rem;
        max-width: 100%;
    }
    
    .member-item {
        padding: 0.75rem;
    }
    
    .member-avatar {
        width: 35px;
        height: 35px;
        font-size: 1.3rem;
    }
    
    .subject-modal {
        padding: 1rem;
        max-width: 100%;
    }
    
    .subject-icon-large {
        width: 2rem;
        height: 2rem;
    }
    
    .subject-stats {
        gap: 0.5rem;
    }
    
    .subject-stat .stat-number {
        font-size: 1rem;
    }
    
    .subject-stat .stat-label {
        font-size: 0.6rem;
    }
    
    .content-item {
        padding: 0.5rem;
    }
    
    .content-icon {
        width: 1rem;
        height: 1rem;
    }
    
    .group-chat {
        height: 300px;
    }
    
    .chat-message {
        gap: 0.5rem;
    }
    
    .message-avatar {
        width: 28px;
        height: 28px;
        font-size: 1rem;
    }
    
    .message-content {
        max-width: 80%;
        padding: 0.5rem 0.75rem;
    }
    
    .chat-input {
        padding: 0.75rem;
        gap: 0.25rem;
    }
    
    .chat-input input {
        padding: 0.5rem 0.75rem;
        font-size: 0.8rem;
    }
    
    .chat-input .action-btn {
        padding: 0.5rem 1rem;
        font-size: 0.8rem;
    }
}

@media (max-width: 360px) {
    .quick-actions {
        grid-template-columns: 1fr;
    }
    
    .nav-item {
        min-width: 45px;
    }
    
    .nav-label {
        font-size: 0.5rem;
    }
    
    .main-content {
        padding: 0.75rem;
        padding-bottom: 90px;
    }
}

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

@keyframes slideIn {
    from { 
        transform: translateX(100%); 
    }
    to { 
        transform: translateX(0); 
    }
}

@keyframes glow {
    0%, 100% {
        box-shadow: var(--shadow-neon);
    }
    50% {
        box-shadow: var(--shadow-glow);
    }
}

.content-screen {
    animation: fadeIn 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles for keyboard navigation */
button:focus, input:focus {
    outline: 2px solid var(--neon-green);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --bg-primary: #000000;
        --bg-secondary: #1a1a1a;
        --text-primary: #ffffff;
        --text-secondary: #cccccc;
    }
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb {
    background: var(--gradient-primary);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--neon-green);
}

/* Light Mode Scrollbar */
[data-theme="light"] ::-webkit-scrollbar-thumb {
    background: linear-gradient(135deg, #3B82F6, #22C55E);
}

[data-theme="light"] ::-webkit-scrollbar-thumb:hover {
    background: #3B82F6;
}

/* Light Mode Additional Enhancements */
[data-theme="light"] .welcome-section {
    border: 1px solid rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow-card);
}

[data-theme="light"] .quick-action-btn {
    border: 1px solid rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow-card);
}

[data-theme="light"] .quick-action-btn:hover {
    border-color: rgba(59, 130, 246, 0.3);
    box-shadow: var(--shadow-floating);
}

[data-theme="light"] .activity-list {
    border: 1px solid rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow-card);
}

[data-theme="light"] .calendar-grid {
    border: 1px solid rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow-card);
}

[data-theme="light"] .modal-content {
    border: 1px solid rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow-floating);
}

[data-theme="light"] .pomodoro-container {
    border: 1px solid rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow-floating);
}

/* Light Mode Progress Indicators */
[data-theme="light"] .timer-circle::before {
    border-top-color: #3B82F6;
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.2);
}

/* Light Mode Button Enhancements */
[data-theme="light"] .action-btn {
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.2);
}

[data-theme="light"] .action-btn:hover {
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.3);
}

[data-theme="light"] .icon-btn {
    border: 1px solid rgba(59, 130, 246, 0.1);
    box-shadow: var(--shadow-card);
}

[data-theme="light"] .icon-btn:hover {
    border-color: rgba(59, 130, 246, 0.3);
    box-shadow: var(--shadow-floating);
}