/* JLEARN FLAWLESS DESIGN SYSTEM v3.0 */
/* Loaded AFTER styles.css and modern-enhancements.css */

/* === 1. ROOT TOKENS === */
:root {
    --primary-color: #4f46e5;
    --primary-dark: #3730a3;
    --primary-light: #eef2ff;
    --primary-50: #eef2ff;
    --primary-100: #e0e7ff;
    --primary-200: #c7d2fe;
    --primary-500: #6366f1;
    --primary-600: #4f46e5;
    --primary-700: #4338ca;
    --secondary-color: #06b6d4;
    --secondary-dark: #0891b2;
    --secondary-light: #cffafe;
    --success-color: #10b981;
    --success-light: #d1fae5;
    --warning-color: #f59e0b;
    --warning-light: #fef3c7;
    --danger-color: #ef4444;
    --danger-light: #fee2e2;
    --info-color: #3b82f6;
    --info-light: #dbeafe;
    --bg-color: #f8fafc;
    --bg-secondary: #f1f5f9;
    --surface-color: #ffffff;
    --surface-elevated: #ffffff;
    --text-color: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border-color: #e2e8f0;
    --border-light: #f1f5f9;
    --hover-bg: #f8fafc;
    --shadow-xs: 0 1px 2px rgba(15,23,42,.04);
    --shadow-sm: 0 1px 3px rgba(15,23,42,.06),0 1px 2px rgba(15,23,42,.04);
    --shadow: 0 4px 6px -1px rgba(15,23,42,.07),0 2px 4px -2px rgba(15,23,42,.05);
    --shadow-md: 0 6px 12px -2px rgba(15,23,42,.08),0 3px 6px -2px rgba(15,23,42,.04);
    --shadow-lg: 0 12px 24px -4px rgba(15,23,42,.10),0 6px 12px -4px rgba(15,23,42,.06);
    --shadow-xl: 0 24px 48px -8px rgba(15,23,42,.14),0 12px 24px -6px rgba(15,23,42,.08);
    --shadow-primary: 0 4px 14px rgba(79,70,229,.25);
    --shadow-primary-lg: 0 8px 24px rgba(79,70,229,.30);
    --radius-xs: 6px;
    --radius-sm: 8px;
    --radius: 12px;
    --radius-md: 14px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-2xl: 24px;
    --radius-full: 9999px;
    --transition: all .25s cubic-bezier(.4,0,.2,1);
    --transition-fast: all .15s cubic-bezier(.4,0,.2,1);
    --font-sans: 'Poppins',-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
    --font-display: 'Poppins',-apple-system,BlinkMacSystemFont,sans-serif;
}

[data-theme="dark"] {
    --primary-color: #818cf8;
    --primary-dark: #6366f1;
    --primary-light: #312e81;
    --primary-50: #1e1b4b;
    --primary-100: #312e81;
    --primary-200: #3730a3;
    --primary-500: #6366f1;
    --primary-600: #818cf8;
    --primary-700: #a5b4fc;
    --secondary-color: #22d3ee;
    --secondary-dark: #06b6d4;
    --secondary-light: #155e75;
    --bg-color: #0b1120;
    --bg-secondary: #0f172a;
    --surface-color: #1e293b;
    --surface-elevated: #243044;
    --text-color: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --border-color: #334155;
    --border-light: #1e293b;
    --hover-bg: #243044;
    --shadow-xs: 0 1px 2px rgba(0,0,0,.2);
    --shadow-sm: 0 1px 3px rgba(0,0,0,.3),0 1px 2px rgba(0,0,0,.2);
    --shadow: 0 4px 6px -1px rgba(0,0,0,.3),0 2px 4px -2px rgba(0,0,0,.2);
    --shadow-md: 0 6px 12px -2px rgba(0,0,0,.35),0 3px 6px -2px rgba(0,0,0,.2);
    --shadow-lg: 0 12px 24px -4px rgba(0,0,0,.4),0 6px 12px -4px rgba(0,0,0,.25);
    --shadow-xl: 0 24px 48px -8px rgba(0,0,0,.45),0 12px 24px -6px rgba(0,0,0,.3);
    --shadow-primary: 0 4px 14px rgba(99,102,241,.3);
    --shadow-primary-lg: 0 8px 24px rgba(99,102,241,.35);
}

/* === 2. BASE TYPOGRAPHY === */
*{ -webkit-font-smoothing:antialiased; -moz-osx-font-smoothing:grayscale; text-rendering:optimizeLegibility; }

body {
    font-family: var(--font-sans);
    font-size: 15px;
    line-height: 1.65;
    color: var(--text-color);
    background-color: var(--bg-color);
    letter-spacing: -.01em;
}

h1,h2,h3,h4,h5,h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.25;
    letter-spacing: -.02em;
    color: var(--text-color);
}
h1{font-size:clamp(2rem,5vw,3.5rem);font-weight:800;}
h2{font-size:clamp(1.5rem,4vw,2.5rem);font-weight:700;}
h3{font-size:clamp(1.25rem,3vw,1.75rem);font-weight:700;}
h4{font-size:clamp(1.1rem,2.5vw,1.375rem);font-weight:600;}
h5{font-size:1.125rem;font-weight:600;}
h6{font-size:1rem;font-weight:600;}
p{line-height:1.7;color:var(--text-secondary);}
a{color:var(--primary-color);transition:var(--transition-fast);}
a:hover{color:var(--primary-dark);}
strong,b{font-weight:700;color:var(--text-color);}
small{font-size:.8125rem;color:var(--text-muted);}
::selection{background:var(--primary-100);color:var(--primary-700);}
[data-theme="dark"] ::selection{background:rgba(129,140,248,.3);color:#c7d2fe;}

/* === 3. SCROLLBAR === */
::-webkit-scrollbar{width:10px;height:10px;}
::-webkit-scrollbar-track{background:var(--bg-secondary);}
::-webkit-scrollbar-thumb{background:var(--border-color);border-radius:var(--radius-full);border:2px solid var(--bg-secondary);}
::-webkit-scrollbar-thumb:hover{background:var(--text-muted);}
[data-theme="dark"] ::-webkit-scrollbar-track{background:#0b1120;}
[data-theme="dark"] ::-webkit-scrollbar-thumb{background:#334155;border-color:#0b1120;}
*{scrollbar-width:thin;scrollbar-color:var(--border-color) var(--bg-secondary);}

/* === 4. NAVBAR === */
.navbar {
    background: rgba(255,255,255,.85);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid rgba(226,232,240,.8);
    box-shadow: 0 1px 3px rgba(15,23,42,.04);
    padding: .875rem 0;
}
[data-theme="dark"] .navbar {
    background: rgba(15,23,42,.85);
    border-bottom: 1px solid rgba(51,65,85,.6);
}
.nav-brand {
    font-family: var(--font-display);
    font-weight: 800;
    font-size: 1.5rem;
    letter-spacing: -.03em;
    background: linear-gradient(135deg,var(--primary-color),var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    gap: .625rem;
}
.nav-brand i {
    background: linear-gradient(135deg,var(--primary-color),var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 1.6rem;
}
.theme-toggle {
    width: 40px; height: 40px;
    border-radius: var(--radius-full);
    display: flex; align-items: center; justify-content: center;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}
.theme-toggle:hover {
    background: var(--primary-50);
    border-color: var(--primary-color);
    transform: rotate(15deg);
}
[data-theme="dark"] .theme-toggle:hover { background: var(--primary-100); }
#teacher-name-display, #student-name-display {
    font-weight: 600; font-size: .875rem;
    color: var(--text-secondary);
    padding: .5rem .875rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-full);
    border: 1px solid var(--border-color);
}

/* === 5. HERO === */
.hero {
    padding: 5rem 0 4rem;
    background: linear-gradient(135deg,#4f46e5 0%,#6366f1 30%,#06b6d4 100%);
    color: white; position: relative; overflow: hidden;
}
.hero::before {
    content: ''; position: absolute;
    top: -50%; left: -20%; width: 600px; height: 600px;
    background: radial-gradient(circle,rgba(255,255,255,.08) 0%,transparent 70%);
    border-radius: 50%; animation: heroFloat 20s ease-in-out infinite;
}
.hero::after {
    content: ''; position: absolute;
    bottom: -30%; right: -10%; width: 500px; height: 500px;
    background: radial-gradient(circle,rgba(6,182,212,.12) 0%,transparent 70%);
    border-radius: 50%; animation: heroFloat 25s ease-in-out infinite reverse;
}
@keyframes heroFloat {
    0%,100%{transform:translate(0,0) scale(1);}
    50%{transform:translate(30px,-30px) scale(1.1);}
}
.hero-content { text-align: center; max-width: 640px; margin: 0 auto; position: relative; z-index: 1; }
.hero h1 { color: white; font-size: clamp(2.25rem,5vw,3.5rem); font-weight: 800; margin-bottom: 1rem; text-shadow: 0 2px 20px rgba(0,0,0,.15); }
.hero p { color: rgba(255,255,255,.92); font-size: 1.2rem; margin-bottom: 2rem; font-weight: 400; }
.hero-buttons { gap: 1rem; }
.hero-illustration { position: relative; z-index: 1; }
.hero-illustration i { font-size: 8rem; opacity: .15; animation: heroFloat 15s ease-in-out infinite; }

/* === 6. BUTTONS === */
.btn {
    padding: .75rem 1.5rem;
    border: none;
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: .9375rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: .5rem;
    min-height: 42px;
    box-sizing: border-box;
    position: relative;
    overflow: hidden;
    white-space: nowrap;
    text-decoration: none;
    letter-spacing: -.01em;
}
.btn::after {
    content: ''; position: absolute;
    top: 0; left: -100%; width: 100%; height: 100%;
    background: linear-gradient(90deg,transparent,rgba(255,255,255,.2),transparent);
    transition: left .5s;
}
.btn:hover::after { left: 100%; }
.btn-primary {
    background: linear-gradient(135deg,var(--primary-color),var(--primary-500));
    color: white;
    box-shadow: var(--shadow-primary);
}
.btn-primary:hover {
    background: linear-gradient(135deg,var(--primary-dark),var(--primary-color));
    transform: translateY(-2px);
    box-shadow: var(--shadow-primary-lg);
}
.btn-primary:active { transform: translateY(0); }
.btn-secondary {
    background: linear-gradient(135deg,var(--secondary-color),var(--secondary-dark));
    color: white;
    box-shadow: 0 4px 14px rgba(6,182,212,.25);
}
.btn-secondary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(6,182,212,.3);
}
.btn-success {
    background: linear-gradient(135deg,#10b981,#059669);
    color: white;
    box-shadow: 0 4px 14px rgba(16,185,129,.25);
}
.btn-success:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(16,185,129,.3); }
.btn-danger {
    background: linear-gradient(135deg,#ef4444,#dc2626);
    color: white;
    box-shadow: 0 4px 14px rgba(239,68,68,.25);
}
.btn-danger:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(239,68,68,.3); }
.btn-info {
    background: linear-gradient(135deg,#3b82f6,#2563eb);
    color: white;
    box-shadow: 0 4px 14px rgba(59,130,246,.25);
}
.btn-info:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(59,130,246,.3); }
.btn-text { background: none; color: var(--text-secondary); }
.btn-text:hover { background: var(--bg-secondary); color: var(--text-color); }
.btn:disabled, .btn[disabled] { opacity: .55; cursor: not-allowed; transform: none !important; pointer-events: none; }
.btn:focus-visible { outline: 3px solid var(--primary-200); outline-offset: 2px; }
.btn-block { width: 100%; }
.btn-large { padding: 1rem 2rem; font-size: 1.1rem; min-width: 200px; min-height: 50px; }
.btn-sm { padding: .5rem 1rem; font-size: .8125rem; min-height: 34px; }

/* === 7. CARDS & SURFACES === */
.feature-card, .login-card, .stat-card, .lesson-card, .completion-card, .video-card, .table-container {
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-light);
    transition: var(--transition);
}
.feature-card {
    padding: 2rem;
    border-radius: var(--radius-lg);
    text-align: center;
}
.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-200);
}
.feature-card i { font-size: 2.5rem; color: var(--primary-color); margin-bottom: 1rem; }
.feature-card h3 { margin-bottom: .5rem; font-size: 1.25rem; }
.feature-card p { color: var(--text-secondary); font-size: .9375rem; }

/* === 8. LOGIN CARDS === */
.login-card {
    padding: 2.5rem;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    max-width: 460px;
    width: 100%;
    border: 1px solid var(--border-light);
}
.login-header { text-align: center; margin-bottom: 2rem; }
.login-header i {
    font-size: 3.5rem;
    background: linear-gradient(135deg,var(--primary-color),var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1rem;
}
.login-header h2 { margin-bottom: .5rem; font-size: 1.75rem; }
.login-header p { color: var(--text-secondary); font-size: .9375rem; }
.login-help {
    margin-top: 1.5rem; padding: 1rem;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    text-align: center;
    font-size: .875rem;
    color: var(--text-secondary);
    border: 1px solid var(--border-light);
}

/* === 9. FORMS === */
.form-group { margin-bottom: 1.25rem; }
.form-group label {
    display: flex; align-items: center; gap: .5rem;
    margin-bottom: .5rem;
    font-weight: 600; font-size: .875rem;
    color: var(--text-color);
    letter-spacing: -.01em;
}
.form-group label i { color: var(--primary-color); font-size: .9rem; }
.form-group input, .form-group textarea, .form-group select {
    width: 100%;
    padding: .75rem .875rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: .9375rem;
    background-color: var(--surface-color);
    color: var(--text-color);
    transition: var(--transition-fast);
}
.form-group input:focus, .form-group textarea:focus, .form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px var(--primary-50);
}
[data-theme="dark"] .form-group input:focus,
[data-theme="dark"] .form-group textarea:focus,
[data-theme="dark"] .form-group select:focus {
    box-shadow: 0 0 0 4px rgba(99,102,241,.15);
}
.form-group input::placeholder, .form-group textarea::placeholder {
    color: var(--text-muted);
}
.form-group small { display: block; margin-top: .25rem; color: var(--text-muted); font-size: .8125rem; }

/* === 10. STAT CARDS === */
.stat-card {
    padding: 1.75rem;
    border-radius: var(--radius-lg);
    display: flex; align-items: center; gap: 1.25rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-light);
    transition: var(--transition);
}
.stat-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.stat-card i {
    font-size: 2.5rem;
    width: 56px; height: 56px;
    display: flex; align-items: center; justify-content: center;
    border-radius: var(--radius);
    background: var(--primary-50);
    color: var(--primary-color);
    flex-shrink: 0;
}
[data-theme="dark"] .stat-card i { background: var(--primary-100); }
.stat-info h3 { font-size: 1.75rem; margin-bottom: .125rem; font-weight: 800; }
.stat-info p { font-size: .875rem; color: var(--text-secondary); margin: 0; }

/* === 11. TABLES === */
.table-container {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-light);
    overflow: hidden;
}
.data-table { width: 100%; border-collapse: collapse; font-size: .875rem; }
.data-table thead {
    background: var(--bg-secondary);
    border-bottom: 2px solid var(--border-color);
}
.data-table th {
    padding: .875rem 1rem;
    font-weight: 700;
    font-size: .8125rem;
    text-transform: uppercase;
    letter-spacing: .03em;
    color: var(--text-secondary);
    border-bottom: 2px solid var(--border-color);
    white-space: nowrap;
}
.data-table td {
    padding: .875rem 1rem;
    border-bottom: 1px solid var(--border-light);
    color: var(--text-color);
}
.data-table tbody tr { transition: var(--transition-fast); }
.data-table tbody tr:hover { background: var(--hover-bg); }
.data-table tbody tr:last-child td { border-bottom: none; }

/* === 12. DASHBOARD SIDEBAR === */
.dashboard-sidebar {
    background: var(--surface-color);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    padding: 1.25rem;
    height: fit-content;
    position: sticky;
    top: 100px;
}
.sidebar-menu { gap: .375rem; }
.menu-item {
    padding: .875rem 1rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: .9rem;
    color: var(--text-secondary);
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: .75rem;
    border: none;
    background: none;
    text-align: left;
    cursor: pointer;
    width: 100%;
    letter-spacing: -.01em;
}
.menu-item i { font-size: 1.15rem; width: 22px; text-align: center; transition: var(--transition); }
.menu-item:hover {
    background: var(--bg-secondary);
    color: var(--text-color);
    transform: translateX(3px);
}
.menu-item:hover i { color: var(--primary-color); transform: scale(1.1); }
.menu-item.active {
    background: linear-gradient(135deg,var(--primary-color),var(--primary-500));
    color: white;
    box-shadow: var(--shadow-primary);
}
.menu-item.active i { color: white; }

/* === 13. LESSON CARDS === */
.lesson-card {
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-light);
    transition: var(--transition);
}
.lesson-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-200);
}
.lesson-card-header { margin-bottom: 1rem; }
.lesson-card-body h3 { font-size: 1.15rem; margin-bottom: .5rem; }
.lesson-code {
    background: linear-gradient(135deg,var(--primary-color),var(--primary-500));
    color: white;
    padding: .3rem .75rem;
    border-radius: var(--radius-full);
    font-size: .75rem;
    font-weight: 700;
    letter-spacing: .02em;
    box-shadow: var(--shadow-xs);
}
.lesson-card-footer { margin-top: 1.25rem; gap: .5rem; }

/* === 14. SECTION HEADERS === */
.section-header {
    margin-bottom: 1.75rem;
}
.section-header h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
}

/* === 15. ASSESSMENT SECTION === */
.assessment-section {
    background: var(--surface-color);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-light);
}
.assessment-header h3 { font-size: 1.35rem; }
.sticky-timer {
    position: sticky;
    top: 70px;
    background: var(--surface-color);
    padding: .875rem 1.25rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    border: 2px solid var(--primary-100);
    display: flex;
    align-items: center;
    gap: .625rem;
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--primary-color);
    z-index: 5;
    transition: var(--transition);
}
[data-theme="dark"] .sticky-timer { border-color: var(--primary-200); }
.sticky-timer i { font-size: 1.25rem; }
.question-card {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius);
    margin-bottom: 1.25rem;
    border: 1px solid var(--border-light);
    transition: var(--transition-fast);
}
.question-card:hover { border-color: var(--primary-200); }
.question-text { font-weight: 600; margin-bottom: 1rem; font-size: 1.05rem; line-height: 1.6; color: var(--text-color); }
.question-number { color: var(--primary-color); font-weight: 800; font-size: 1.1rem; }
.answer-option {
    display: flex;
    align-items: center;
    padding: .875rem 1rem;
    background: var(--surface-color);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    margin-bottom: .5rem;
    cursor: pointer;
    transition: var(--transition-fast);
}
.answer-option:hover {
    border-color: var(--primary-color);
    background: var(--primary-50);
    transform: translateX(4px);
}
[data-theme="dark"] .answer-option:hover { background: rgba(99,102,241,.1); }
.answer-option input[type="radio"] { margin-right: .75rem; flex-shrink: 0; width: 18px; height: 18px; accent-color: var(--primary-color); }
.option-letter { font-weight: 700; color: var(--primary-color); margin-right: .75rem; font-size: 1rem; flex-shrink: 0; min-width: 28px; }
.option-text { flex: 1; line-height: 1.5; color: var(--text-color); }

/* === 16. RESULTS === */
.results-section {
    background: var(--surface-color);
    padding: 2.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-light);
}
.results-card { text-align: center; max-width: 640px; margin: 0 auto; }
.results-icon { font-size: 4.5rem; margin-bottom: 1rem; }
.score-display { margin: 2rem 0; }
.score-circle {
    width: 140px; height: 140px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg,var(--primary-color),var(--secondary-color));
    display: flex; align-items: center; justify-content: center;
    margin: 0 auto 1rem;
    box-shadow: var(--shadow-primary-lg);
}
.score-circle span { font-size: 2.25rem; font-weight: 800; color: white; }
.results-details { text-align: left; margin: 2rem 0; }

/* === 17. MODALS === */
.modal-overlay {
    background: rgba(15,23,42,.5);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
}
.modal {
    background-color: var(--surface-color);
    color: var(--text-color);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-2xl);
    border: 1px solid var(--border-light);
}
.modal-header {
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--border-light);
}
.modal-header h3 { font-size: 1.25rem; font-weight: 700; }
.modal-close {
    width: 36px; height: 36px;
    border-radius: var(--radius-sm);
    display: flex; align-items: center; justify-content: center;
    transition: var(--transition-fast);
}
.modal-close:hover { background: var(--danger-light); color: var(--danger-color); }
.modal form, .result-details-content { padding: 1.5rem; }
.modal-actions { gap: .75rem; margin-top: 1.5rem; }

/* === 18. VIDEO & MATERIALS === */
.video-section {
    background: linear-gradient(135deg,var(--surface-color) 0%,rgba(79,70,229,.03) 100%);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
    border: 1px solid var(--border-light);
}
[data-theme="dark"] .video-section { background: linear-gradient(135deg,var(--surface-color) 0%,rgba(99,102,241,.05) 100%); }
.video-card {
    background: var(--surface-color);
    padding: 1.25rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-xs);
    border: 1px solid var(--border-light);
}
.materials-section {
    background: linear-gradient(135deg,var(--surface-color) 0%,rgba(16,185,129,.03) 100%);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
    border: 1px solid var(--border-light);
}
[data-theme="dark"] .materials-section { background: linear-gradient(135deg,var(--surface-color) 0%,rgba(16,185,129,.05) 100%); }
.section-title { border-bottom: 3px solid var(--primary-color); padding-bottom: .75rem; margin-bottom: 1.5rem; }
.section-title i { font-size: 1.5rem; color: var(--primary-color); }
.section-title h3 { font-size: 1.35rem; font-weight: 700; }
.completion-card {
    padding: 2.5rem 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    text-align: center;
    border: 1px solid var(--border-light);
}
.completion-icon { font-size: 3.5rem; margin-bottom: 1.25rem; }

/* === 19. TABS === */
.tab-btn {
    padding: .75rem 1rem;
    border: none;
    border-bottom: 3px solid transparent;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition-fast);
    font-size: .875rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: .5rem;
    background: none;
}
.tab-btn:hover { color: var(--primary-color); }
.tab-btn.active { color: var(--primary-color); border-bottom-color: var(--primary-color); font-weight: 700; }
.page-tab {
    padding: .625rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition-fast);
    font-size: .875rem;
    font-weight: 600;
    background: var(--surface-color);
}
.page-tab:hover { border-color: var(--primary-color); color: var(--primary-color); transform: translateY(-1px); }
.page-tab.active {
    background: linear-gradient(135deg,var(--primary-color),var(--primary-500));
    border-color: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-primary);
}

/* === 20. EMPTY STATES === */
.empty-state, .empty-state-card {
    text-align: center;
    padding: 3rem 1.5rem;
    color: var(--text-muted);
}
.empty-state i, .empty-state-card i { font-size: 3.5rem; margin-bottom: 1rem; opacity: .4; }
.empty-state p, .empty-state-card p { font-size: .9375rem; }

/* === 21. ERROR & SUCCESS MESSAGES === */
.error-message {
    border-radius: var(--radius);
    border-left: 4px solid var(--danger-color);
    background: linear-gradient(135deg,#fef2f2,#fee2e2);
    color: #991b1b;
    padding: 1rem 1.25rem;
    font-size: .9rem;
    box-shadow: var(--shadow-sm);
}
[data-theme="dark"] .error-message { background: rgba(239,68,68,.1); color: #fca5a5; }
.success-message {
    border-radius: var(--radius);
    background: var(--success-light);
    color: #065f46;
    padding: .875rem 1rem;
    border: 1px solid rgba(16,185,129,.3);
    font-size: .9rem;
}
[data-theme="dark"] .success-message { background: rgba(16,185,129,.1); color: #6ee7b7; }
.instructions-warning {
    border-radius: var(--radius);
    border-left: 4px solid var(--warning-color);
    background: var(--warning-light);
    color: #92400e;
    padding: 1rem;
    font-size: .9rem;
}
[data-theme="dark"] .instructions-warning { background: rgba(245,158,11,.1); color: #fcd34d; }

/* === 22. LOGIN FOOTER LINKS === */
.login-footer { margin-top: 2rem; padding-top: 1.5rem; border-top: 1px solid var(--border-light); }
.login-footer a {
    padding: .5rem 1rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
    background: var(--surface-color);
    color: var(--primary-color);
    font-weight: 600;
    font-size: .875rem;
    transition: var(--transition);
}
.login-footer a:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-primary);
}

/* === 23. FORMAT GUIDE === */
.format-guide {
    border-radius: var(--radius);
    border-left: 4px solid var(--primary-color);
    background: var(--bg-secondary);
    padding: 1rem 1.25rem;
    border: 1px solid var(--border-light);
}
.format-guide strong { color: var(--primary-color); }

/* === 24. INSTRUCTION ITEMS === */
.instruction-item {
    border-radius: var(--radius);
    background: var(--bg-secondary);
    padding: 1rem 1.25rem;
    border: 1px solid var(--border-light);
}
.instruction-item > i { color: var(--primary-color); font-size: 1.35rem; }
.instruction-item strong { font-size: 1rem; color: var(--text-color); }

/* === 25. PAGE TRANSITIONS === */
.page.active { animation: pageFadeIn .35s cubic-bezier(.4,0,.2,1); }
@keyframes pageFadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}
.assessment-tab-content.active, .assessment-page.active, .dashboard-section.active {
    animation: pageFadeIn .3s cubic-bezier(.4,0,.2,1);
}

/* === 26. MOBILE MENU TOGGLE === */
.mobile-menu-toggle {
    display: none;
    width: 42px; height: 42px;
    border-radius: var(--radius-sm);
    align-items: center; justify-content: center;
    transition: var(--transition-fast);
}
.mobile-menu-toggle:hover { background: var(--bg-secondary); }
.mobile-menu-toggle:active { transform: scale(.95); }

/* === 27. FULLSCREEN BUTTON === */
.fullscreen-btn-external {
    border-radius: var(--radius-sm);
    background: linear-gradient(135deg,var(--primary-color),var(--primary-dark));
    box-shadow: var(--shadow-primary);
    padding: .875rem 1.5rem;
    font-weight: 600;
    font-size: .9375rem;
    transition: var(--transition);
}
.fullscreen-btn-external:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-primary-lg);
}

/* === 28. VIDEO PROGRESS BAR === */
.video-progress-bar { height: 6px; border-radius: var(--radius-full); background: var(--border-color); }
.video-progress-fill { border-radius: var(--radius-full); background: linear-gradient(90deg,var(--primary-color),var(--secondary-color)); transition: width .3s ease; }

/* === 29. GROUP HEADER === */
.group-header { background: linear-gradient(135deg,var(--primary-color),var(--primary-500)) !important; }
.group-header td { color: white !important; font-weight: 700 !important; }

/* === 30. RESPONSIVE ENHANCEMENTS === */
@media (max-width: 768px) {
    body { font-size: 15px; }
    p, li, span, div { font-size: 1rem; line-height: 1.6; }
    input, textarea, select { font-size: 16px !important; }
    label { font-size: .95rem; }
    .mobile-menu-toggle { display: flex !important; }
    .hero { padding: 3rem 0 2.5rem; }
    .hero h1 { font-size: 2rem; }
    .hero p { font-size: 1.05rem; }
    .hero-buttons { flex-direction: column; }
    .hero-buttons .btn { width: 100%; }
    .login-card { padding: 1.5rem; border-radius: var(--radius-lg); margin: 1rem; }
    .login-card h2 { font-size: 1.5rem; margin-bottom: 1.5rem; }
    .assessment-section { padding: 1.25rem; border-radius: var(--radius); }
    .results-section { padding: 1.5rem; border-radius: var(--radius); }
    .video-section, .materials-section { padding: 1.25rem; border-radius: var(--radius); }
    .stat-card { padding: 1.25rem; gap: 1rem; border-radius: var(--radius); }
    .stat-card i { width: 48px; height: 48px; font-size: 2rem; }
    .stat-info h3 { font-size: 1.5rem; }
    .feature-card { padding: 1.5rem; }
    .feature-grid, .materials-grid, .stats-grid { grid-template-columns: 1fr; }
    .question-card { padding: 1.25rem; }
    .question-card h4 { font-size: 1.1rem; line-height: 1.4; margin-bottom: 1rem; }
    .question-card p { font-size: .95rem; }
    .answer-option { padding: .75rem; min-height: 54px; }
    .answer-option input[type="radio"] { width: 20px; height: 20px; }
    .option-letter { min-width: 35px; height: 35px; font-size: 1rem; }
    .data-table th { padding: .625rem .75rem; font-size: .75rem; }
    .data-table td { padding: .625rem .75rem; font-size: .8125rem; }
    .menu-item { padding: .75rem .875rem; font-size: .875rem; }
    .modal { border-radius: var(--radius-lg); }
    .modal-header { padding: 1rem 1.25rem; }
    .modal form, .result-details-content { padding: 1.25rem; }
    .modal-actions { gap: .5rem; flex-direction: column-reverse; }
    .modal-actions .btn { width: 100%; min-height: 52px; }
    .score-circle { width: 120px; height: 120px; }
    .score-circle span { font-size: 2rem; }
    .sticky-timer { font-size: 1.15rem; padding: .75rem 1rem; }
    .section-title h3 { font-size: 1.15rem; }
    .section-title { font-size: 1.25rem; margin-bottom: 1rem; padding-bottom: .5rem; }
    .section-description { font-size: .9rem; margin-bottom: 1rem; }
    
    /* Touch-friendly buttons */
    .btn {
        min-height: 48px;
        font-size: 1rem;
        padding: .875rem 1.5rem;
        font-weight: 600;
        border-radius: 8px;
        touch-action: manipulation;
        -webkit-tap-highlight-color: transparent;
        user-select: none;
        -webkit-user-select: none;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        gap: .5rem;
    }
    .btn:active { transform: scale(.98); }
    .btn-sm { min-height: 44px; font-size: .9rem; padding: .75rem 1rem; }
    .btn-lg { min-height: 56px; font-size: 1.1rem; padding: 1rem 2rem; }
    .btn i { font-size: 1.1rem; }
    .btn-block { width: 100%; }
    
    /* Dashboard button & menu item touch optimization */
    .dashboard-section .btn, .section-header .btn {
        touch-action: manipulation;
        -webkit-tap-highlight-color: transparent;
        position: relative;
        z-index: 1;
        min-height: 48px;
        font-weight: 600;
    }
    .dashboard-section .btn:active, .section-header .btn:active { transform: scale(.98); }
    .dashboard-sidebar .menu-item,
    .dashboard-sidebar.active .menu-item {
        pointer-events: auto !important;
        cursor: pointer !important;
        position: relative !important;
        z-index: 1070 !important;
        touch-action: manipulation !important;
        -webkit-tap-highlight-color: rgba(0,0,0,.1) !important;
        user-select: none !important;
        -webkit-user-select: none !important;
    }
    .dashboard-sidebar .menu-item:active,
    .dashboard-sidebar.active .menu-item:active {
        transform: scale(.95) !important;
        background-color: var(--primary-color) !important;
        color: white !important;
    }
    
    /* Video player mobile */
    #video-container {
        height: auto;
        aspect-ratio: 16 / 9;
        max-height: 80vh !important;
        margin: 0 !important;
        width: 100% !important;
    }
    #youtube-player-container {
        height: auto;
        aspect-ratio: 16 / 9;
        max-height: 80vh !important;
        width: 100% !important;
    }
    #youtube-player { width: 100% !important; height: 100% !important; }
    .video-wrapper { max-height: 80vh !important; width: 100% !important; }
    #lesson-video { max-height: 80vh !important; width: 100% !important; object-fit: contain; }
    .video-controls { flex-wrap: wrap; gap: .5rem; margin-top: 1rem; }
    .video-controls .btn { flex: 1; min-width: 140px; }
    
    /* Quiz & assessment mobile */
    .quiz-container { padding: 1rem; }
    .quiz-header { flex-direction: column; gap: .75rem; padding: 1rem; text-align: center; }
    .quiz-timer { font-size: 1.25rem; padding: .75rem 1.5rem; width: 100%; text-align: center; }
    .quiz-questions { padding: 1rem; }
    .option-label { padding: 1rem; font-size: .95rem; min-height: 48px; display: flex; align-items: center; }
    textarea.form-control { font-size: 16px !important; min-height: 120px; padding: 1rem; }
    input[type="text"].form-control { font-size: 16px !important; min-height: 48px; padding: .875rem; }
    .answer-input { font-size: 16px !important; padding: .875rem; width: 100%; }
    textarea.answer-input { min-height: 120px; }
    
    /* Quiz navigation mobile */
    #quiz-navigation {
        flex-direction: column;
        gap: .75rem;
        padding: 1rem;
        background: var(--surface-color);
        position: relative;
        border-top: 1px solid var(--border-color);
        margin-bottom: 1rem;
    }
    #quiz-navigation .btn { flex: 1; min-width: 0; }
    #page-indicator {
        order: -1;
        width: 100%;
        padding: .75rem;
        background: var(--bg-secondary);
        border-radius: var(--radius);
        font-size: 1rem;
        font-weight: 600;
    }
    #prev-page-btn, #next-page-btn, #submit-quiz-btn {
        width: 100%;
        flex: none;
        min-height: 48px;
        font-size: 1rem;
    }
    
    /* Results mobile */
    .results-container { padding: 1rem; }
    .results-header { padding: 1.25rem; }
    .results-header h2 { font-size: 1.35rem; }
    .score-display { font-size: 2.5rem; padding: 1.5rem; }
    .results-summary { gap: 1rem; }
    .summary-item { padding: 1rem; }
    .summary-item h4 { font-size: .9rem; }
    .summary-item p { font-size: 1.5rem; }
    
    /* Empty/loading/alert states */
    .empty-state-card { padding: 2rem 1rem; }
    .empty-state-card i { font-size: 3rem; }
    .empty-state-card p { font-size: 1rem; }
    .loading { font-size: 1rem; padding: 2rem 1rem; }
    .alert { padding: 1rem; font-size: .95rem; border-radius: 8px; }
    
    /* Materials list */
    .materials-list { gap: .75rem; }
    .material-item { padding: 1rem; flex-direction: column; align-items: flex-start; gap: .75rem; }
    .material-info { width: 100%; }
    .material-item .btn { width: 100%; }
    
    /* Documents viewer */
    .documents-viewer { padding: 0; }
    .documents-viewer-header { padding: 1rem; position: sticky; top: 0; background: var(--surface-color); z-index: 10; }
    .documents-list { padding: 1rem; gap: .75rem; }
    .document-item { padding: 1rem; flex-direction: column; align-items: flex-start; gap: .75rem; }
    .document-info { width: 100%; }
    .document-item .btn { width: 100%; }
    
    /* Fullscreen button */
    .fullscreen-btn-external { padding: .75rem 1.25rem; font-size: .95rem; }
    .fullscreen-btn { width: 100%; margin-top: .5rem; }
    
    /* Login footer */
    .login-footer { margin-top: 1.5rem; padding-top: 1rem; gap: .75rem; }
    .login-footer p { font-size: .85rem; flex-direction: column; align-items: stretch; }
    .login-footer a { width: 100%; justify-content: center; padding: .7rem 1rem; font-size: .85rem; }
    
    /* Container */
    .container { padding: 0 16px; }
    .form-group { margin-bottom: 1.25rem; }
    .form-group label { font-size: .95rem; font-weight: 600; }
    .form-control, input[type="text"], input[type="email"], input[type="password"],
    input[type="number"], input[type="datetime-local"], select, textarea {
        font-size: 16px !important;
        padding: .875rem;
        border-radius: 8px;
    }
    textarea { min-height: 150px; resize: vertical; }
    
    /* Body overflow prevention */
    body { overflow-x: hidden !important; max-width: 100vw !important; }
    .container { max-width: 100% !important; width: 100% !important; padding-left: .75rem !important; padding-right: .75rem !important; box-sizing: border-box !important; }
    img, video, iframe { max-width: 100% !important; }
}

@media (max-width: 480px) {
    body { font-size: 14px; }
    .hero h1 { font-size: 1.75rem; }
    .login-card { padding: 1.25rem; }
    .stat-card { flex-direction: column; text-align: center; padding: 1rem; }
    .feature-card { padding: 1.25rem; }
    .assessment-section { padding: 1rem; }
    .results-section { padding: 1.25rem; }
    .video-section, .materials-section { padding: 1rem; }
    .question-card { padding: 1rem; }
    .question-card h4 { font-size: 1rem; }
    .answer-option { padding: .625rem .75rem; font-size: .875rem; }
    .data-table th { padding: .5rem .5rem; font-size: .7rem; }
    .data-table td { padding: .5rem .5rem; font-size: .75rem; }
    .btn { width: 100%; padding: .75rem 1rem; min-height: 44px; }
    .btn-sm { min-height: 36px; padding: .5rem .75rem; font-size: .85rem; }
    #video-container, #youtube-player-container { max-height: 75vh !important; }
    .video-wrapper { max-height: 75vh !important; }
    .video-controls .btn { width: 100%; flex: none; }
    .modal-header { padding: .75rem; flex-direction: column; align-items: stretch; gap: .75rem; }
    .modal-header h3 { font-size: 1.1rem; text-align: center; margin-bottom: .5rem; }
    .modal form { padding: .75rem; padding-bottom: 7rem; }
    .modal-actions { padding: .75rem; gap: .5rem; }
    .modal-actions .btn { padding: 1rem; font-size: .95rem; border-radius: 8px; }
    .form-group div[style*="grid-template-columns"] { grid-template-columns: 1fr !important; gap: 1rem !important; }
    #videos-container { gap: 1rem !important; }
    .video-input-group { padding: 1rem; border: 1px solid var(--border-color); border-radius: 8px; background: var(--bg-color); }
    #documents-container { gap: 1rem !important; }
    .document-input-group { padding: 1rem; border: 1px solid var(--border-color); border-radius: 8px; background: var(--bg-color); }
    .assessment-page { margin-bottom: 1.5rem; }
    .assessment-page textarea { min-height: 200px; font-size: 14px; line-height: 1.5; }
    .btn[onclick*="preview"] { width: 100%; margin-top: .5rem; padding: .75rem; }
}

@media (max-width: 400px) {
    .nav-brand span { display: none !important; }
    .nav-brand i { font-size: 1.5rem !important; }
}