/* ========================================
   TKA SD Kelas 6 - Design System
   ======================================== */

:root {
    /* Colors */
    --primary: #6366f1;
    --primary-light: #818cf8;
    --primary-dark: #4f46e5;
    --primary-50: #eef2ff;
    --primary-100: #e0e7ff;
    --primary-200: #c7d2fe;

    --accent: #a855f7;
    --accent-light: #c084fc;

    --success: #10b981;
    --success-light: #d1fae5;
    --warning: #f59e0b;
    --warning-light: #fef3c7;
    --danger: #ef4444;
    --danger-light: #fee2e2;

    --math-color: #6366f1;
    --math-bg: #eef2ff;
    --science-color: #10b981;
    --science-bg: #d1fae5;
    --indo-color: #f59e0b;
    --indo-bg: #fef3c7;
    --social-color: #ef4444;
    --social-bg: #fee2e2;

    /* Neutrals */
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #94a3b8;
    --border: #e2e8f0;
    --border-light: #f1f5f9;

    /* Spacing */
    --section-padding: 100px 0;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.04);
    --shadow-glow: 0 0 40px rgba(99,102,241,0.15);

    /* Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;

    /* Transitions */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s ease;
    --transition-bounce: all 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* =================== BASE =================== */

*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--text-primary);
    background: var(--bg-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

h1, h2, h3, h4 { line-height: 1.2; font-weight: 700; }
h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.6rem, 3.5vw, 2.5rem); }
h3 { font-size: 1.25rem; }

a { text-decoration: none; color: inherit; }
button { cursor: pointer; border: none; font-family: inherit; }

.hidden { display: none !important; }

/* =================== BUTTONS =================== */

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: var(--radius-full);
    font-size: 0.95rem;
    font-weight: 600;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    box-shadow: 0 4px 15px rgba(99,102,241,0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(99,102,241,0.5);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border);
}

.btn-secondary:hover {
    border-color: var(--primary);
    color: var(--primary);
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: var(--text-secondary);
    border: 2px solid var(--border);
    padding: 12px 24px;
}

.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.btn-outline:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.btn-outline:disabled:hover {
    border-color: var(--border);
    color: var(--text-secondary);
}

/* =================== NAVBAR =================== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(226, 232, 240, 0.5);
    transition: var(--transition);
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    font-size: 1.2rem;
    color: var(--text-primary);
}

.logo-icon {
    display: flex;
}

.nav-links {
    display: flex;
    gap: 8px;
}

.nav-link {
    padding: 8px 16px;
    border-radius: var(--radius-full);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition);
}

.nav-link:hover, .nav-link.active {
    color: var(--primary);
    background: var(--primary-50);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    padding: 8px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

/* =================== HERO =================== */

.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #eef2ff 0%, #f5f3ff 30%, #fdf2f8 60%, #fff7ed 100%);
    overflow: hidden;
    padding-top: 72px;
}

.hero-bg-shapes {
    position: absolute;
    inset: 0;
    overflow: hidden;
    pointer-events: none;
}

.shape {
    position: absolute;
    border-radius: 50%;
    opacity: 0.1;
    animation: float 20s ease-in-out infinite;
}

.shape-1 {
    width: 400px;
    height: 400px;
    background: var(--primary);
    top: -100px;
    right: -100px;
    animation-delay: 0s;
}

.shape-2 {
    width: 300px;
    height: 300px;
    background: var(--accent);
    bottom: -50px;
    left: -50px;
    animation-delay: -5s;
}

.shape-3 {
    width: 200px;
    height: 200px;
    background: var(--warning);
    top: 50%;
    left: 30%;
    animation-delay: -10s;
}

.shape-4 {
    width: 150px;
    height: 150px;
    background: var(--success);
    top: 20%;
    right: 20%;
    animation-delay: -15s;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(30px, -30px) scale(1.05); }
    50% { transform: translate(-20px, 20px) scale(0.95); }
    75% { transform: translate(15px, 10px) scale(1.02); }
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    padding: 60px 24px;
    position: relative;
    z-index: 2;
}

.hero-badge {
    display: inline-block;
    padding: 8px 20px;
    background: var(--bg-secondary);
    border-radius: var(--radius-full);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--primary);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--primary-100);
    margin-bottom: 20px;
    animation: fadeInUp 0.6s ease forwards;
}

.hero-text h1 {
    margin-bottom: 20px;
    animation: fadeInUp 0.6s 0.1s ease both;
}

.gradient-text {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    color: var(--text-secondary);
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 32px;
    max-width: 540px;
    animation: fadeInUp 0.6s 0.2s ease both;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 48px;
    animation: fadeInUp 0.6s 0.3s ease both;
}

.hero-stats {
    display: flex;
    gap: 40px;
    animation: fadeInUp 0.6s 0.4s ease both;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 2rem;
    font-weight: 800;
    color: var(--primary);
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    font-weight: 500;
}

/* Hero Illustration */
.hero-illustration {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeInRight 0.8s 0.3s ease both;
}

.hero-mascot {
    position: relative;
    z-index: 1;
    animation: mascotBounce 3s ease-in-out infinite;
    filter: drop-shadow(0 20px 40px rgba(99,102,241,0.2));
}

@keyframes mascotBounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-15px); }
}

.floating-cards {
    position: absolute;
    inset: 0;
    z-index: 2;
}

.float-card {
    position: absolute;
    background: white;
    padding: 12px 18px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 600;
    font-size: 0.85rem;
    box-shadow: var(--shadow-lg);
    animation: floatCard 4s ease-in-out infinite;
    animation-delay: var(--delay);
}

.float-card .card-icon {
    font-size: 1.3rem;
}

.card-math { top: 10%; left: -10%; }
.card-science { top: 5%; right: -5%; }
.card-indo { bottom: 20%; left: -15%; }
.card-social { bottom: 10%; right: -10%; }

@keyframes floatCard {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-12px) rotate(2deg); }
}

.hero-wave {
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    line-height: 0;
}

.hero-wave svg {
    width: 100%;
    height: 80px;
}

/* =================== SECTION HEADERS =================== */

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-badge {
    display: inline-block;
    padding: 6px 18px;
    background: var(--primary-50);
    border-radius: var(--radius-full);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 16px;
}

.section-header h2 {
    margin-bottom: 12px;
}

.section-header p {
    color: var(--text-secondary);
    font-size: 1.05rem;
    max-width: 500px;
    margin: 0 auto;
}

/* =================== SUBJECTS =================== */

.subjects {
    padding: var(--section-padding);
    background: var(--bg-primary);
}

.subjects-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.subject-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 32px 24px;
    text-align: center;
    border: 1px solid var(--border-light);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.subject-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transform: scaleX(0);
    transition: var(--transition);
}

.subject-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-200);
}

.subject-card:hover::before {
    transform: scaleX(1);
}

.subject-icon-wrapper {
    width: 72px;
    height: 72px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    transition: var(--transition);
}

.math-bg { background: var(--math-bg); color: var(--math-color); }
.science-bg { background: var(--science-bg); color: var(--science-color); }
.indo-bg { background: var(--indo-bg); color: var(--indo-color); }
.social-bg { background: var(--social-bg); color: var(--social-color); }

.subject-card:hover .subject-icon-wrapper {
    transform: scale(1.1) rotate(5deg);
}

.subject-card h3 {
    margin-bottom: 10px;
}

.subject-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: 16px;
}

.subject-meta {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-bottom: 20px;
    font-size: 0.85rem;
}

.question-count {
    color: var(--primary);
    font-weight: 600;
    background: var(--primary-50);
    padding: 4px 12px;
    border-radius: var(--radius-full);
}

.btn-subject {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    padding: 10px 24px;
    border-radius: var(--radius-full);
    font-size: 0.9rem;
    font-weight: 600;
    transition: var(--transition);
    width: 100%;
}

.btn-subject:hover {
    box-shadow: 0 4px 15px rgba(99,102,241,0.4);
    transform: translateY(-1px);
}

/* =================== QUIZ SECTION =================== */

.mix-card {
    grid-column: 1 / -1;
    max-width: 600px;
    margin: 0 auto;
}


.quiz-section {
    padding: var(--section-padding);
    background: linear-gradient(180deg, var(--bg-primary), #eef2ff);
}

.quiz-selector {
    max-width: 800px;
    margin: 0 auto;
}

.quick-start-cards {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 16px;
}

.quick-card {
    background: var(--bg-secondary);
    border: 2px solid var(--border-light);
    border-radius: var(--radius-lg);
    padding: 28px 16px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    transition: var(--transition-bounce);
    cursor: pointer;
}

.quick-card:hover {
    transform: translateY(-6px) scale(1.02);
    border-color: var(--primary);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.quick-icon {
    font-size: 2rem;
}

.quick-label {
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.quick-count {
    font-size: 0.8rem;
    color: var(--text-tertiary);
    background: var(--bg-tertiary);
    padding: 2px 10px;
    border-radius: var(--radius-full);
}

.quick-card-mix {
    background: linear-gradient(135deg, var(--primary-50), #f5f3ff);
    border-color: var(--primary-200);
}

/* =================== QUIZ CONTAINER =================== */

.quiz-container {
    max-width: 760px;
    margin: 0 auto;
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    padding: 40px;
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--border-light);
    animation: fadeInUp 0.5s ease;
}

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

.quiz-info {
    display: flex;
    align-items: center;
    gap: 12px;
}

.quiz-subject-label {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    padding: 6px 16px;
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 600;
}

.quiz-progress-text {
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 500;
}

.quiz-timer {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

.quiz-progress-bar {
    height: 6px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    margin-bottom: 36px;
    overflow: hidden;
}

.quiz-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: var(--radius-full);
    transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.quiz-question-area {
    margin-bottom: 32px;
}

.question-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: white;
    border-radius: 50%;
    font-weight: 700;
    font-size: 1rem;
    margin-bottom: 16px;
}

.question-text {
    font-size: 1.1rem;
    line-height: 1.7;
    color: var(--text-primary);
    margin-bottom: 28px;
    font-weight: 500;
}

.options-grid {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.option-btn {
    display: flex;
    align-items: flex-start;
    gap: 14px;
    padding: 16px 20px;
    background: var(--bg-primary);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
    font-size: 0.95rem;
    line-height: 1.5;
    color: var(--text-primary);
    width: 100%;
}

.option-btn:hover {
    border-color: var(--primary-light);
    background: var(--primary-50);
    transform: translateX(4px);
}

.option-btn.selected {
    border-color: var(--primary);
    background: var(--primary-50);
    box-shadow: 0 0 0 3px rgba(99,102,241,0.1);
}

.option-btn.correct {
    border-color: var(--success);
    background: var(--success-light);
}

.option-btn.wrong {
    border-color: var(--danger);
    background: var(--danger-light);
}

.option-letter {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--bg-secondary);
    border: 2px solid var(--border);
    font-weight: 700;
    font-size: 0.85rem;
    color: var(--text-secondary);
    transition: var(--transition);
    flex-shrink: 0;
}

.option-btn.selected .option-letter {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

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

.option-btn.wrong .option-letter {
    background: var(--danger);
    border-color: var(--danger);
    color: white;
}

.option-text {
    padding-top: 4px;
}

.quiz-actions {
    display: flex;
    justify-content: space-between;
    gap: 12px;
}

.btn-submit {
    margin-left: auto;
}

/* =================== RESULTS =================== */

.quiz-results {
    max-width: 700px;
    margin: 0 auto;
    animation: fadeInUp 0.5s ease;
}

.results-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
    padding: 48px 40px;
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--border-light);
    text-align: center;
}

.results-header {
    margin-bottom: 32px;
}

.results-emoji {
    font-size: 4rem;
    margin-bottom: 12px;
    animation: bounceIn 0.6s ease;
}

.results-header h3 {
    font-size: 1.5rem;
    margin-bottom: 8px;
}

.results-header p {
    color: var(--text-secondary);
}

.results-score-ring {
    position: relative;
    width: 160px;
    height: 160px;
    margin: 0 auto 32px;
}

.results-score-ring svg {
    width: 100%;
    height: 100%;
}

.score-text {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.score-value {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.score-label {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    font-weight: 500;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin-bottom: 36px;
}

.result-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    padding: 16px;
    border-radius: var(--radius-md);
    background: var(--bg-primary);
}

.result-stat-icon { font-size: 1.3rem; }
.result-stat-value { font-size: 1.5rem; font-weight: 800; }
.result-stat-label { font-size: 0.8rem; color: var(--text-tertiary); }

.result-stat.correct .result-stat-value { color: var(--success); }
.result-stat.wrong .result-stat-value { color: var(--danger); }
.result-stat.unanswered .result-stat-value { color: var(--warning); }

.results-review {
    text-align: left;
    margin-bottom: 32px;
}

.results-review h4 {
    font-size: 1.1rem;
    margin-bottom: 16px;
    text-align: center;
}

.review-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
    max-height: 500px;
    overflow-y: auto;
    padding-right: 8px;
}

.review-item {
    background: var(--bg-primary);
    border-radius: var(--radius-md);
    padding: 20px;
    border-left: 4px solid var(--border);
    text-align: left;
}

.review-item.review-correct {
    border-left-color: var(--success);
}

.review-item.review-wrong {
    border-left-color: var(--danger);
}

.review-item.review-unanswered {
    border-left-color: var(--warning);
}

.review-question {
    font-weight: 600;
    margin-bottom: 8px;
    font-size: 0.95rem;
    line-height: 1.5;
}

.review-answer {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 4px;
}

.review-answer span {
    font-weight: 600;
}

.review-answer.answer-correct span {
    color: var(--success);
}

.review-answer.answer-wrong span {
    color: var(--danger);
}

.review-explanation {
    font-size: 0.85rem;
    color: var(--text-secondary);
    background: var(--bg-secondary);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    margin-top: 8px;
    line-height: 1.5;
}

.review-explanation strong {
    color: var(--primary);
}

.results-actions {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
}

/* =================== TIPS SECTION =================== */

.tips-section {
    padding: var(--section-padding);
    background: var(--bg-secondary);
}

.tips-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.tip-card {
    position: relative;
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    padding: 32px 24px;
    border: 1px solid var(--border-light);
    transition: var(--transition);
    overflow: hidden;
}

.tip-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.tip-number {
    position: absolute;
    top: 16px;
    right: 20px;
    font-size: 3rem;
    font-weight: 800;
    color: var(--primary-50);
    line-height: 1;
}

.tip-icon {
    font-size: 2rem;
    margin-bottom: 16px;
}

.tip-card h3 {
    margin-bottom: 10px;
}

.tip-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* =================== FOOTER =================== */

.footer {
    background: var(--text-primary);
    color: #cbd5e1;
    padding: 60px 0 0;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 48px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer-brand .nav-logo span {
    color: white;
}

.footer-brand p {
    margin-top: 12px;
    font-size: 0.9rem;
    line-height: 1.6;
    max-width: 320px;
}

.footer-links h4 {
    color: white;
    margin-bottom: 16px;
    font-size: 1rem;
}

.footer-links a {
    display: block;
    padding: 6px 0;
    font-size: 0.9rem;
    color: #94a3b8;
    transition: var(--transition-fast);
}

.footer-links a:hover {
    color: white;
    transform: translateX(4px);
}

.footer-bottom {
    padding: 20px 0;
    text-align: center;
    font-size: 0.85rem;
    color: #64748b;
}

/* =================== ANIMATIONS =================== */

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

@keyframes fadeInRight {
    from { opacity: 0; transform: translateX(50px); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes bounceIn {
    0% { transform: scale(0); }
    50% { transform: scale(1.2); }
    100% { transform: scale(1); }
}

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

.animate-on-scroll {
    opacity: 0;
    transform: translateY(40px);
    transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* =================== RESPONSIVE =================== */

@media (max-width: 1024px) {
    .subjects-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-description { margin: 0 auto 32px; }
    .hero-actions { justify-content: center; }
    .hero-stats { justify-content: center; }

    .hero-illustration {
        max-width: 300px;
        margin: 0 auto;
    }

    .quick-start-cards {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 768px) {
    :root {
        --section-padding: 60px 0;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background: var(--bg-secondary);
        flex-direction: column;
        padding: 16px;
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow-lg);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-toggle {
        display: flex;
    }

    .hero {
        min-height: auto;
        padding-top: 72px;
        padding-bottom: 80px;
    }

    .hero-content {
        padding: 40px 24px;
    }

    .floating-cards { display: none; }

    .subjects-grid {
        grid-template-columns: 1fr;
    }

    .quick-start-cards {
        grid-template-columns: repeat(2, 1fr);
    }

    .quick-card-mix {
        grid-column: span 2;
    }

    .quiz-container {
        padding: 24px;
    }

    .tips-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .results-card {
        padding: 32px 20px;
    }

    .results-stats {
        grid-template-columns: repeat(3, 1fr);
        gap: 8px;
    }

    .quiz-actions {
        flex-direction: column;
    }

    .quiz-actions .btn {
        width: 100%;
        justify-content: center;
    }

    .btn-submit {
        margin-left: 0;
    }
}

@media (max-width: 480px) {
    .hero-stats {
        gap: 24px;
    }

    .stat-number {
        font-size: 1.5rem;
    }

    .quick-start-cards {
        grid-template-columns: 1fr 1fr;
    }

    .quiz-header {
        flex-direction: column;
        gap: 8px;
        align-items: flex-start;
    }
}

/* Scrollbar */
.review-list::-webkit-scrollbar {
    width: 6px;
}

.review-list::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
    border-radius: 3px;
}

.review-list::-webkit-scrollbar-thumb {
    background: var(--primary-200);
    border-radius: 3px;
}

.review-list::-webkit-scrollbar-thumb:hover {
    background: var(--primary-light);
}