/* ==================== BASE STYLES ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #10b981;
    --accent: #f59e0b;
    --danger: #ef4444;
    --bg-dark: #0f172a;
    --bg-card: #1e293b;
    --bg-input: #334155;
    --border: #475569;
    --text: #f8fafc;
    --text-muted: #94a3b8;
    --text-dark: #64748b;
    --success: #22c55e;
    --warning: #eab308;
    --radius: 12px;
    --radius-sm: 8px;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    --transition: all 0.2s ease;
}

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background: var(--bg-dark);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ==================== LOADING ==================== */
.loading-screen {
    position: fixed;
    inset: 0;
    background: var(--bg-dark);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 16px;
    z-index: 9999;
}

.loading-screen.hidden { display: none; }

.loader {
    width: 40px;
    height: 40px;
    border: 3px solid var(--bg-card);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ==================== SCREENS ==================== */
.screen {
    display: none;
    min-height: 100vh;
}

.screen.active { display: block; }

/* ==================== AUTH SCREENS ==================== */
.auth-screen {
    display: none;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, var(--bg-dark) 0%, #1a1a3e 100%);
}

.auth-screen.active { display: flex; }

.auth-card {
    width: 100%;
    max-width: 420px;
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 40px;
    box-shadow: var(--shadow);
}

.auth-header {
    text-align: center;
    margin-bottom: 32px;
}

.logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
}

.auth-header h1 {
    font-size: 24px;
    margin: 16px 0 8px;
}

.auth-header p { color: var(--text-muted); }

.auth-footer {
    text-align: center;
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
}

.auth-footer p {
    margin: 8px 0;
    color: var(--text-muted);
}

.auth-footer a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}

/* Password Toggle */
.password-input-wrapper {
    position: relative;
    display: flex;
}

.password-input-wrapper input {
    flex: 1;
    padding-right: 50px;
}

.toggle-password {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    font-size: 18px;
    opacity: 0.6;
    transition: var(--transition);
}

.toggle-password:hover { opacity: 1; }
.toggle-password.active { opacity: 1; color: var(--primary); }

/* ==================== FORMS ==================== */
.form-group { margin-bottom: 20px; }

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-muted);
    font-size: 14px;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px 16px;
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text);
    font-family: inherit;
    font-size: 16px;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.form-group textarea {
    min-height: 100px;
    resize: vertical;
}

.form-group small {
    display: block;
    margin-top: 6px;
    color: var(--text-dark);
    font-size: 12px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.form-notice {
    background: rgba(99, 102, 241, 0.1);
    border: 1px solid rgba(99, 102, 241, 0.3);
    border-radius: var(--radius-sm);
    padding: 12px 16px;
    margin-top: 16px;
}

.form-notice p {
    font-size: 13px;
    color: var(--text-muted);
    margin: 0;
}

@media (max-width: 600px) {
    .form-row { grid-template-columns: 1fr; }
    .auth-card { padding: 24px; }
}

/* ==================== BUTTONS ==================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    white-space: nowrap;
}

.btn-primary {
    background: var(--primary);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
}

.btn-primary:disabled {
    background: var(--text-dark);
    cursor: not-allowed;
    transform: none;
}

.btn-secondary {
    background: var(--secondary);
    color: white;
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text);
}

.btn-outline:hover { background: var(--bg-input); }

.btn-ghost {
    background: transparent;
    color: var(--text-muted);
}

.btn-ghost:hover {
    color: var(--text);
    background: var(--bg-input);
}

.btn-danger { background: var(--danger); color: white; }
.btn-block { width: 100%; }
.btn-lg { padding: 16px 32px; font-size: 16px; }
.btn-sm { padding: 8px 16px; font-size: 13px; }

/* ==================== HEADER ==================== */
.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 20px;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    gap: 16px;
}

.header-left,
.header-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.header-nav {
    display: flex;
    gap: 4px;
}

.nav-link {
    padding: 8px 16px;
    color: var(--text-muted);
    text-decoration: none;
    border-radius: var(--radius-sm);
    font-weight: 500;
    font-size: 14px;
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--text);
    background: var(--bg-input);
}

.nav-link.active {
    color: var(--primary);
    background: rgba(99, 102, 241, 0.1);
}

.user-name {
    color: var(--text-muted);
    font-size: 14px;
}

.admin-badge {
    background: var(--accent);
    color: #000;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 11px;
    font-weight: 600;
    margin-left: 8px;
}

.admin-header {
    background: linear-gradient(90deg, var(--bg-card) 0%, #1e1e3f 100%);
}

/* Burger Menu */
.burger-menu {
    display: none;
    background: none;
    border: none;
    color: var(--text);
    font-size: 24px;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    z-index: 99;
}

.mobile-menu-overlay.active { display: block; }

@media (max-width: 768px) {
    .burger-menu { display: block; }
    
    .header-nav {
        position: fixed;
        top: 0;
        left: -280px;
        width: 280px;
        height: 100vh;
        background: var(--bg-card);
        flex-direction: column;
        padding: 80px 20px 20px;
        gap: 8px;
        z-index: 101;
        transition: left 0.3s ease;
        border-right: 1px solid var(--border);
    }
    
    .header-nav.active { left: 0; }
    
    .nav-link {
        padding: 12px 16px;
        width: 100%;
    }
    
    .user-name { display: none; }
    
    .logo { font-size: 20px; }
}

/* ==================== MAIN CONTENT ==================== */
.main-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 24px 20px;
}

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
    flex-wrap: wrap;
    gap: 16px;
}

.section { margin-bottom: 40px; }

.section h2 {
    font-size: 20px;
    margin-bottom: 16px;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.view-all {
    color: var(--primary);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
}

.subtitle {
    color: var(--text-muted);
    margin-bottom: 24px;
}

.welcome-banner {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    padding: 32px;
    border-radius: var(--radius);
    margin-bottom: 32px;
}

.welcome-banner h1 { font-size: 24px; margin-bottom: 8px; }
.welcome-banner p { opacity: 0.9; }

.empty-state {
    text-align: center;
    padding: 48px 24px;
    color: var(--text-muted);
}

/* ==================== COURSES GRID ==================== */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}

.course-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    transition: var(--transition);
    cursor: pointer;
}

.course-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: 0 12px 40px rgba(99, 102, 241, 0.15);
}

.course-thumb {
    position: relative;
    aspect-ratio: 16/9;
    background: var(--bg-input);
    overflow: hidden;
}

.course-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.course-badge {
    position: absolute;
    top: 12px;
    left: 12px;
    background: var(--primary);
    color: white;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

.course-badge.owned { background: var(--secondary); }

.course-progress-bar {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: rgba(255,255,255,0.2);
}

.course-progress-fill {
    height: 100%;
    background: var(--secondary);
}

.course-body { padding: 16px; }

.course-title {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 8px;
    line-height: 1.4;
}

.course-meta {
    display: flex;
    gap: 16px;
    color: var(--text-muted);
    font-size: 13px;
    margin-bottom: 12px;
}

.course-price {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary);
}

.course-actions {
    display: flex;
    gap: 8px;
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid var(--border);
    flex-wrap: wrap;
}

/* ==================== COURSE DETAIL ==================== */
.course-detail-header {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    margin-bottom: 40px;
}

@media (max-width: 900px) {
    .course-detail-header { grid-template-columns: 1fr; }
}

.course-detail-img {
    width: 100%;
    aspect-ratio: 16/9;
    object-fit: cover;
    border-radius: var(--radius);
    background: var(--bg-card);
}

.course-detail-info h1 {
    font-size: 28px;
    margin-bottom: 12px;
}

.course-desc {
    color: var(--text-muted);
    margin-bottom: 20px;
    line-height: 1.7;
}

.facilitator-info {
    background: var(--bg-input);
    border-radius: var(--radius-sm);
    padding: 16px;
    margin-bottom: 20px;
}

.facilitator-info h4 {
    font-size: 14px;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.facilitator-info .name {
    font-size: 16px;
    font-weight: 600;
}

.facilitator-info .bio {
    font-size: 13px;
    color: var(--text-muted);
    margin-top: 8px;
}

.course-detail-info .course-price {
    font-size: 28px;
    margin-bottom: 20px;
}

.course-detail-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

/* Lessons List */
.lessons-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.lesson-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    padding: 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
}

.lesson-item:hover {
    border-color: var(--primary);
    background: var(--bg-input);
}

.lesson-item.completed .lesson-number { background: var(--secondary); }
.lesson-item.locked { opacity: 0.5; cursor: not-allowed; }
.lesson-item.locked:hover { border-color: var(--border); background: var(--bg-card); }

.lesson-number {
    width: 36px;
    height: 36px;
    min-width: 36px;
    background: var(--bg-input);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 14px;
}

.lesson-info { flex: 1; }

.lesson-info h4 {
    font-size: 15px;
    margin-bottom: 4px;
}

.lesson-description {
    font-size: 13px;
    color: var(--text-muted);
    margin: 6px 0;
    line-height: 1.5;
}

.lesson-meta {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 12px;
    color: var(--text-dark);
    background: var(--bg-dark);
    padding: 4px 10px;
    border-radius: 4px;
    margin-top: 8px;
}

/* ==================== VIDEO PLAYER ==================== */
.player-header {
    background: rgba(15, 23, 42, 0.98);
    padding: 10px 16px;
}

.player-course-title {
    font-weight: 600;
    font-size: 14px;
    color: var(--text-muted);
}

.progress-badge {
    background: var(--secondary);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
}

.player-layout {
    display: flex;
    height: calc(100vh - 57px);
    position: relative;
}

.player-main {
    flex: 1;
    overflow-y: auto;
    background: var(--bg-dark);
}

/* Video Container */
.video-container {
    background: #000;
    position: relative;
}

.video-wrapper {
    position: relative;
    width: 100%;
    aspect-ratio: 16/9;
    max-height: 70vh;
    background: #000;
    user-select: none;
    overflow: hidden;
}

#youtubePlayer {
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.video-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 60px;
    z-index: 5;
    cursor: pointer;
}

/* Video Controls */
.video-controls {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(transparent, rgba(0,0,0,0.95));
    padding: 40px 16px 12px;
    z-index: 20;
    opacity: 1;
    transition: opacity 0.3s ease;
}

.video-wrapper.controls-hidden .video-controls {
    opacity: 0;
    pointer-events: none;
}

.video-wrapper:hover .video-controls,
.video-wrapper.controls-visible .video-controls {
    opacity: 1;
    pointer-events: auto;
}

.progress-bar {
    position: relative;
    height: 20px;
    cursor: pointer;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
}

.progress-bar::before {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    height: 5px;
    background: rgba(255,255,255,0.2);
    border-radius: 3px;
}

.progress-fill {
    position: absolute;
    left: 0;
    height: 5px;
    background: var(--primary);
    border-radius: 3px;
    width: 0%;
}

.progress-handle {
    position: absolute;
    width: 14px;
    height: 14px;
    background: var(--primary);
    border-radius: 50%;
    left: 0%;
    transform: translateX(-50%);
    opacity: 0;
    transition: opacity 0.2s;
}

.progress-bar:hover .progress-handle { opacity: 1; }

.controls-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
}

.controls-left,
.controls-right {
    display: flex;
    align-items: center;
    gap: 8px;
}

.control-btn {
    width: 40px;
    height: 40px;
    background: rgba(255,255,255,0.1);
    border: none;
    border-radius: 50%;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.control-btn:hover { background: rgba(255,255,255,0.2); }

.control-btn svg {
    width: 20px;
    height: 20px;
    fill: white;
}

.play-btn {
    width: 48px;
    height: 48px;
    background: var(--primary);
}

.play-btn:hover { background: var(--primary-dark); }

.volume-slider-container {
    width: 0;
    overflow: hidden;
    transition: width 0.2s;
}

.controls-left:hover .volume-slider-container,
.volume-slider-container:focus-within {
    width: 80px;
}

.volume-slider {
    width: 80px;
    height: 4px;
    accent-color: var(--primary);
}

.time-display {
    color: white;
    font-size: 13px;
    font-variant-numeric: tabular-nums;
}

.speed-control { position: relative; }

.speed-btn {
    width: auto;
    padding: 0 12px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
}

.speed-menu {
    display: none;
    position: absolute;
    bottom: 100%;
    right: 0;
    margin-bottom: 8px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    z-index: 30;
    min-width: 80px;
}

.speed-menu.active { display: block; }

.speed-option {
    display: block;
    width: 100%;
    padding: 10px 16px;
    background: none;
    border: none;
    color: white;
    text-align: center;
    cursor: pointer;
    font-size: 13px;
}

.speed-option:hover,
.speed-option.active {
    background: var(--primary);
}

/* Mobile Video Controls */
@media (max-width: 600px) {
    .video-controls { padding: 30px 12px 10px; }
    
    .control-btn { width: 36px; height: 36px; }
    .control-btn svg { width: 18px; height: 18px; }
    .play-btn { width: 44px; height: 44px; }
    
    .time-display { font-size: 11px; }
    .speed-btn { padding: 0 10px; font-size: 12px; }
    
    .volume-slider-container { display: none; }
}

/* ==================== PLAYER SIDEBAR ==================== */
.player-sidebar {
    width: 340px;
    background: var(--bg-card);
    border-left: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px;
    border-bottom: 1px solid var(--border);
}

.sidebar-header h3 { font-size: 16px; }

.sidebar-close {
    display: none;
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 24px;
    cursor: pointer;
}

.sidebar-lessons {
    flex: 1;
    overflow-y: auto;
}

.sidebar-lesson {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 14px 16px;
    border-bottom: 1px solid var(--border);
    cursor: pointer;
    transition: var(--transition);
}

.sidebar-lesson:hover { background: var(--bg-input); }

.sidebar-lesson.active {
    background: rgba(99, 102, 241, 0.1);
    border-left: 3px solid var(--primary);
}

.sidebar-lesson.completed .lesson-number { background: var(--secondary); }

.sidebar-lesson.locked {
    opacity: 0.4;
    cursor: not-allowed;
}

.sidebar-lesson .lesson-number {
    width: 28px;
    height: 28px;
    min-width: 28px;
    font-size: 12px;
}

.sidebar-lesson .lesson-info h4 { font-size: 13px; }
.sidebar-lesson .lesson-meta { font-size: 11px; padding: 2px 6px; }

/* Sidebar Toggle */
.sidebar-toggle {
    display: none;
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 56px;
    height: 56px;
    background: var(--primary);
    border: none;
    border-radius: 50%;
    color: white;
    font-size: 24px;
    cursor: pointer;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
    z-index: 50;
}

@media (max-width: 900px) {
    .player-sidebar {
        position: fixed;
        top: 57px;
        right: -340px;
        height: calc(100vh - 57px);
        z-index: 100;
        transition: right 0.3s ease;
    }
    
    .player-sidebar.active { right: 0; }
    
    .sidebar-close { display: block; }
    .sidebar-toggle { display: flex; align-items: center; justify-content: center; }
}

/* ==================== LESSON CONTENT ==================== */
.lesson-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 24px 20px;
}

.lesson-content h2 {
    font-size: 22px;
    margin-bottom: 8px;
}

.lesson-desc {
    color: var(--text-muted);
    margin-bottom: 24px;
}

/* Activities */
.activities-section {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 24px;
}

.activities-section h3 { margin-bottom: 16px; }

.activity-item {
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}

.activity-item:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.activity-prompt {
    font-weight: 500;
    margin-bottom: 10px;
}

.activity-input {
    width: 100%;
    padding: 12px;
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text);
    font-family: inherit;
}

.checkbox-group,
.radio-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.checkbox-label,
.radio-label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    padding: 10px 12px;
    background: var(--bg-input);
    border-radius: var(--radius-sm);
}

.checkbox-label input,
.radio-label input {
    width: 18px;
    height: 18px;
    accent-color: var(--primary);
}

/* Feedback */
.feedback-section {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 24px;
}

.feedback-section h3 { margin-bottom: 16px; }

.feedback-list {
    max-height: 300px;
    overflow-y: auto;
    margin-bottom: 20px;
}

.feedback-item {
    background: var(--bg-input);
    border-radius: var(--radius-sm);
    padding: 14px;
    margin-bottom: 10px;
}

.feedback-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 6px;
}

.feedback-name { font-weight: 600; font-size: 14px; }
.feedback-date { color: var(--text-muted); font-size: 12px; }
.feedback-text { color: var(--text-muted); font-size: 14px; margin-bottom: 6px; }
.feedback-rating { color: var(--warning); font-size: 14px; }

.feedback-form { border-top: 1px solid var(--border); padding-top: 16px; }

.rating-input {
    display: flex;
    gap: 6px;
    margin-bottom: 12px;
}

.star {
    font-size: 28px;
    color: var(--text-dark);
    cursor: pointer;
    transition: var(--transition);
}

.star:hover,
.star.active {
    color: var(--warning);
    transform: scale(1.1);
}

.feedback-form textarea {
    width: 100%;
    padding: 12px;
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text);
    font-family: inherit;
    min-height: 80px;
    margin-bottom: 12px;
    resize: vertical;
}

/* Lesson Nav */
.lesson-nav {
    display: flex;
    justify-content: space-between;
    padding-top: 20px;
    border-top: 1px solid var(--border);
    gap: 12px;
}

.lesson-nav .btn { flex: 1; max-width: 200px; }

@media (max-width: 500px) {
    .lesson-nav { flex-direction: column; }
    .lesson-nav .btn { max-width: 100%; }
}

/* ==================== CERTIFICATE ==================== */
.certificate-page {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 40px 20px;
}

.certificate {
    background: white;
    padding: 16px;
    border-radius: var(--radius);
    max-width: 700px;
    width: 100%;
}

.certificate-border {
    border: 3px solid var(--primary);
    padding: 32px;
}

.certificate-content {
    text-align: center;
    color: #1a1a2e;
}

.certificate-logo { font-size: 40px; margin-bottom: 12px; }

.certificate-content h1 {
    font-size: 28px;
    color: var(--primary);
    margin-bottom: 20px;
}

.certificate-subtitle { font-size: 14px; color: #666; margin-bottom: 6px; }
.certificate-name { font-size: 32px; color: #1a1a2e; margin-bottom: 20px; font-style: italic; }
.certificate-text { font-size: 14px; color: #666; margin-bottom: 6px; }
.certificate-course { font-size: 22px; color: var(--primary); margin-bottom: 20px; }
.certificate-date { color: #666; margin-bottom: 24px; }

.certificate-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 20px;
    border-top: 2px solid #eee;
}

.certificate-brand { font-size: 20px; font-weight: 800; color: var(--primary); }
.certificate-id { font-size: 11px; color: #999; }

.certificate-actions {
    display: flex;
    gap: 12px;
    margin-top: 24px;
    flex-wrap: wrap;
    justify-content: center;
}

/* ==================== ADMIN STYLES ==================== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px;
    margin-bottom: 32px;
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    text-align: center;
}

.stat-card.clickable {
    cursor: pointer;
    transition: var(--transition);
}

.stat-card.clickable:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}

.stat-value {
    font-size: 32px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 4px;
}

.stat-label { color: var(--text-muted); font-size: 14px; }
.stat-sub { color: var(--text-dark); font-size: 12px; margin-top: 8px; }

/* Payment Summary */
.payment-summary {
    display: flex;
    gap: 16px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.summary-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 16px 24px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.summary-label { font-size: 12px; color: var(--text-muted); }
.summary-value { font-size: 20px; font-weight: 700; }
.summary-value.fees { color: var(--danger); }
.summary-value.success { color: var(--success); }

/* Feedback Admin */
.feedback-stats {
    display: flex;
    gap: 24px;
    margin-bottom: 24px;
}

.feedback-stat {
    display: flex;
    align-items: center;
    gap: 8px;
}

.feedback-stat .stat-value {
    font-size: 24px;
    margin-bottom: 0;
}

.feedback-stat .stat-label {
    font-size: 13px;
}

.feedback-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 16px;
}

.admin-feedback-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
}

.admin-feedback-card .course-name {
    font-size: 11px;
    color: var(--primary);
    margin-bottom: 4px;
}

.admin-feedback-card .lesson-name {
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 8px;
}

/* Filters */
.filters {
    display: flex;
    gap: 12px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.filters select,
.filters input {
    padding: 10px 14px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text);
    font-size: 14px;
    min-width: 180px;
}

/* Tables */
.table-wrapper {
    overflow-x: auto;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    -webkit-overflow-scrolling: touch;
}

.data-table {
    width: 100%;
    min-width: 600px;
    border-collapse: collapse;
}

.data-table th,
.data-table td {
    padding: 14px 16px;
    text-align: left;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

.data-table th {
    background: var(--bg-input);
    font-weight: 600;
    font-size: 12px;
    text-transform: uppercase;
    color: var(--text-muted);
}

.data-table tbody tr:hover { background: var(--bg-input); }

.data-table code {
    background: var(--bg-dark);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 12px;
}

.status {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 11px;
    font-weight: 600;
}

.status.success { background: rgba(34, 197, 94, 0.2); color: var(--success); }
.status.failed { background: rgba(239, 68, 68, 0.2); color: var(--danger); }
.status.abandoned { background: rgba(234, 179, 8, 0.2); color: var(--warning); }
.status.pending { background: rgba(148, 163, 184, 0.2); color: var(--text-muted); }

/* Student Detail */
.student-detail { max-width: 900px; }

.student-header {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 32px;
}

.student-avatar {
    width: 72px;
    height: 72px;
    background: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    font-weight: 700;
}

.student-courses,
.student-responses { margin-bottom: 32px; }

.student-courses h2,
.student-responses h2 { margin-bottom: 16px; }

.progress-course-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 12px;
}

.progress-course-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.progress-course-title { font-weight: 600; }
.progress-percent { color: var(--secondary); font-weight: 600; }

.progress-track {
    height: 8px;
    background: var(--bg-input);
    border-radius: 4px;
    overflow: hidden;
}

.progress-track-fill {
    height: 100%;
    background: var(--secondary);
}

.response-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 12px;
}

.response-lesson {
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--primary);
}

.response-item {
    margin-bottom: 12px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
}

.response-item:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.response-question { font-weight: 500; margin-bottom: 6px; font-size: 14px; }

.response-answer {
    color: var(--text-muted);
    background: var(--bg-input);
    padding: 10px;
    border-radius: var(--radius-sm);
    font-size: 14px;
}

/* ==================== MODALS ==================== */
.modal {
    display: none;
    position: fixed;
    inset: 0;
    z-index: 1000;
    align-items: flex-start;
    justify-content: center;
    padding: 20px;
    overflow-y: auto;
}

.modal.active { display: flex; }

.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
}

.modal-content {
    position: relative;
    background: var(--bg-card);
    border-radius: var(--radius);
    width: 100%;
    max-width: 500px;
    margin: auto;
    display: flex;
    flex-direction: column;
    max-height: none;
}

.modal-body {
    padding: 20px;
    overflow-y: visible;
    flex: 1;
    max-height: 60vh;
    overflow-y: auto;
}

@media (max-height: 700px) {
    .modal {
        align-items: flex-start;
        padding: 10px;
    }
    
    .modal-content {
        margin: 10px auto;
    }
    
    .modal-body {
        max-height: 50vh;
    }
}

.modal-lg { max-width: 650px; }
.modal-xl { max-width: 900px; }

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
}

.modal-header h2 { font-size: 18px; }

.btn-close {
    width: 32px;
    height: 32px;
    background: var(--bg-input);
    border: none;
    border-radius: 50%;
    color: var(--text);
    font-size: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-close:hover { background: var(--danger); }

.modal-body {
    padding: 20px;
    overflow-y: auto;
    flex: 1;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    padding: 16px 20px;
    border-top: 1px solid var(--border);
}

/* Course Editor */
.course-editor { padding: 0 !important; }

.editor-tabs {
    display: flex;
    border-bottom: 1px solid var(--border);
    overflow-x: auto;
}

.tab-btn {
    flex: 1;
    min-width: 100px;
    padding: 14px 16px;
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    white-space: nowrap;
}

.tab-btn:hover { color: var(--text); background: var(--bg-input); }

.tab-btn.active {
    color: var(--primary);
    border-bottom: 2px solid var(--primary);
}

.editor-tab-content { padding: 20px; }

.tab-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 12px;
}

.lessons-editor-list,
.activities-editor-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.editor-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px;
    background: var(--bg-input);
    border-radius: var(--radius-sm);
}

.editor-item-info { flex: 1; min-width: 0; }
.editor-item-title { font-weight: 600; margin-bottom: 2px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.editor-item-meta { font-size: 12px; color: var(--text-muted); }

.editor-item-actions {
    display: flex;
    gap: 6px;
    flex-shrink: 0;
}

/* ==================== TOAST ==================== */
.toast-container {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-width: 90vw;
}

.toast {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 14px 18px;
    display: flex;
    align-items: center;
    gap: 10px;
    box-shadow: var(--shadow);
    animation: slideIn 0.3s ease;
    font-size: 14px;
}

.toast.success { border-left: 4px solid var(--success); }
.toast.error { border-left: 4px solid var(--danger); }
.toast.info { border-left: 4px solid var(--primary); }

@keyframes slideIn {
    from { opacity: 0; transform: translateX(100px); }
    to { opacity: 1; transform: translateX(0); }
}

/* ==================== UTILITIES ==================== */
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }

/* Scrollbar */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--bg-dark); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-dark); }

/* Print Styles */
@media print {
    .certificate { box-shadow: none; }
    .certificate-actions { display: none; }
    .header { display: none; }
}

/* ==================== ABOUT US PAGE ==================== */
.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-section {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 24px;
}

.about-section h2 {
    margin-bottom: 16px;
    color: var(--primary);
}

.about-section p {
    color: var(--text-muted);
    line-height: 1.8;
    margin-bottom: 12px;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin-top: 16px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: var(--bg-input);
    border-radius: var(--radius-sm);
}

.contact-item .icon {
    font-size: 24px;
}

.contact-item .label {
    font-size: 12px;
    color: var(--text-muted);
}

.contact-item .value {
    font-weight: 600;
}

/* ==================== STUDENT DASHBOARD IMPROVED ==================== */
.dashboard-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 12px;
    margin-bottom: 24px;
}

.dashboard-stat {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 16px;
    text-align: center;
}

.dashboard-stat .value {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}

.dashboard-stat .label {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 4px;
}

.dashboard-stat.completed .value { color: var(--success); }
.dashboard-stat.in-progress .value { color: var(--accent); }

.enrolled-courses-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.enrolled-course-item {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
}

.enrolled-course-item:hover {
    border-color: var(--primary);
}

.enrolled-course-thumb {
    width: 120px;
    height: 68px;
    border-radius: var(--radius-sm);
    object-fit: cover;
    background: var(--bg-input);
}

.enrolled-course-info {
    flex: 1;
}

.enrolled-course-info h4 {
    margin-bottom: 4px;
}

.enrolled-course-info .meta {
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.enrolled-course-info .status-badge {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 11px;
    font-weight: 600;
}

.status-badge.completed {
    background: rgba(34, 197, 94, 0.2);
    color: var(--success);
}

.status-badge.in-progress {
    background: rgba(245, 158, 11, 0.2);
    color: var(--accent);
}

.status-badge.not-started {
    background: rgba(148, 163, 184, 0.2);
    color: var(--text-muted);
}

.enrolled-course-progress {
    width: 100px;
    text-align: right;
}

.enrolled-course-progress .percent {
    font-size: 18px;
    font-weight: 700;
    color: var(--secondary);
}

.enrolled-course-progress .mini-bar {
    height: 4px;
    background: var(--bg-input);
    border-radius: 2px;
    margin-top: 4px;
    overflow: hidden;
}

.enrolled-course-progress .mini-fill {
    height: 100%;
    background: var(--secondary);
}

@media (max-width: 600px) {
    .enrolled-course-item {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .enrolled-course-thumb {
        width: 100%;
        height: auto;
        aspect-ratio: 16/9;
    }
    
    .enrolled-course-progress {
        width: 100%;
        text-align: left;
        margin-top: 8px;
    }
}

/* ==================== ENROLLMENT COUNT & COURSE INFO ==================== */
.course-stats {
    display: flex;
    gap: 16px;
    margin: 16px 0;
    flex-wrap: wrap;
}

.course-stat-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: var(--bg-input);
    border-radius: var(--radius-sm);
    font-size: 14px;
}

.course-stat-item .icon {
    font-size: 18px;
}

/* ==================== COMMUNITY FEEDBACK ==================== */
.community-rating {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    background: var(--bg-input);
    border-radius: var(--radius-sm);
    margin-bottom: 16px;
}

.community-rating .avg-rating {
    font-size: 32px;
    font-weight: 700;
    color: var(--warning);
}

.community-rating .rating-details {
    flex: 1;
}

.community-rating .stars {
    color: var(--warning);
    font-size: 18px;
}

.community-rating .count {
    font-size: 13px;
    color: var(--text-muted);
}

/* ==================== ENROLLMENT DATE ==================== */
.enrollment-date {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 4px;
}

/* Course Feedback Section */
.course-feedback-section {
    margin-top: 32px;
    padding-top: 32px;
    border-top: 1px solid var(--border);
}

.course-feedback-section h2 {
    margin-bottom: 16px;
}

.course-feedback-section .feedback-list {
    max-height: 400px;
    overflow-y: auto;
}

.course-feedback-section .feedback-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 16px;
    margin-bottom: 12px;
}