/* ============================================
   CODE ACADEMY — Learning Portal Styles
   ============================================ */

/* === Design Tokens === */
:root {
    /* Colors */
    --bg-primary: #0a0e1a;
    --bg-secondary: #111827;
    --bg-card: #1a1f35;
    --bg-card-hover: #222845;
    --bg-surface: #151a2e;

    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;

    --accent-primary: #6c5ce7;
    --accent-primary-glow: rgba(108, 92, 231, 0.3);
    --accent-secondary: #00cec9;
    --accent-secondary-glow: rgba(0, 206, 201, 0.3);
    --accent-warm: #fd79a8;
    --accent-warm-glow: rgba(253, 121, 168, 0.2);
    --accent-success: #00b894;
    --accent-error: #e17055;
    --accent-warning: #fdcb6e;

    --gradient-primary: linear-gradient(135deg, #6c5ce7, #a29bfe);
    --gradient-secondary: linear-gradient(135deg, #00cec9, #81ecec);
    --gradient-warm: linear-gradient(135deg, #fd79a8, #fab1a0);
    --gradient-hero: linear-gradient(135deg, #6c5ce7 0%, #00cec9 50%, #fd79a8 100%);

    /* Borders */
    --border-color: rgba(255, 255, 255, 0.06);
    --border-accent: rgba(108, 92, 231, 0.3);

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 30px rgba(108, 92, 231, 0.15);

    /* Spacing */
    --nav-height: 72px;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* === Reset & Base === */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

::selection {
    background: var(--accent-primary);
    color: white;
}

::-webkit-scrollbar {
    width: 8px;
}
::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}
::-webkit-scrollbar-thumb {
    background: var(--accent-primary);
    border-radius: 4px;
}

/* === Ambient Background === */
.ambient-bg {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.4;
    animation: float 20s infinite ease-in-out;
}

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

.orb-2 {
    width: 300px;
    height: 300px;
    background: var(--accent-secondary);
    bottom: -50px;
    left: -50px;
    animation-delay: -7s;
}

.orb-3 {
    width: 250px;
    height: 250px;
    background: var(--accent-warm);
    top: 50%;
    left: 50%;
    animation-delay: -14s;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(50px, -30px) scale(1.1); }
    50% { transform: translate(-20px, 40px) scale(0.95); }
    75% { transform: translate(30px, 20px) scale(1.05); }
}

/* === Navigation === */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    background: rgba(10, 14, 26, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 2rem;
    z-index: 1000;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.brand-icon {
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-family: 'JetBrains Mono', monospace;
}

.brand-text {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    gap: 0.25rem;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.85rem;
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-family: 'Inter', sans-serif;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
}

.nav-btn:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.05);
}

.nav-btn.active {
    color: var(--accent-primary);
    background: rgba(108, 92, 231, 0.1);
}

.nav-btn.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 50%;
    transform: translateX(-50%);
    width: 24px;
    height: 2px;
    background: var(--accent-primary);
    border-radius: 1px;
}

.nav-icon {
    font-size: 1.1rem;
}

.nav-progress {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.progress-ring {
    width: 42px;
    height: 42px;
    position: relative;
}

.progress-ring svg {
    width: 100%;
    height: 100%;
    transform: rotate(-90deg);
}

.progress-bg-ring {
    fill: none;
    stroke: rgba(255, 255, 255, 0.08);
    stroke-width: 3;
}

.progress-fill-ring {
    fill: none;
    stroke: var(--accent-primary);
    stroke-width: 3;
    stroke-linecap: round;
    transition: stroke-dasharray var(--transition-slow);
}

.progress-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 0.6rem;
    font-weight: 700;
    color: var(--text-secondary);
}

/* === Main Content === */
.main-content {
    position: relative;
    z-index: 1;
    padding-top: var(--nav-height);
    min-height: 100vh;
}

.section {
    display: none;
    padding: 2rem;
    max-width: 1400px;
    margin: 0 auto;
    animation: fadeIn 0.4s ease;
}

.section.active {
    display: block;
}

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

.section-header {
    text-align: center;
    margin-bottom: 2.5rem;
}

.section-title {
    font-size: 2rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    margin-bottom: 0.5rem;
}

.section-desc {
    color: var(--text-secondary);
    font-size: 1.05rem;
}

.section-heading {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

/* === Buttons === */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.65rem 1.5rem;
    border: none;
    border-radius: var(--radius-sm);
    font-family: 'Inter', sans-serif;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 15px var(--accent-primary-glow);
}
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px var(--accent-primary-glow);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.06);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}
.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.15);
}

.btn-accent {
    background: rgba(0, 206, 201, 0.1);
    color: var(--accent-secondary);
    border: 1px solid rgba(0, 206, 201, 0.2);
}
.btn-accent:hover {
    background: rgba(0, 206, 201, 0.2);
}

.btn-lg {
    padding: 0.85rem 2rem;
    font-size: 1rem;
    border-radius: var(--radius-md);
}

.btn-sm {
    padding: 0.45rem 1rem;
    font-size: 0.8rem;
}

.btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    transform: none !important;
}

/* === Hero Section === */
.hero {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    min-height: calc(70vh - var(--nav-height));
    padding: 2rem 0;
}

.hero-badge {
    display: inline-block;
    padding: 0.4rem 1rem;
    background: rgba(108, 92, 231, 0.15);
    color: var(--accent-primary);
    border: 1px solid rgba(108, 92, 231, 0.3);
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    letter-spacing: 0.02em;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.04em;
    margin-bottom: 1.5rem;
}

.gradient-text {
    background: var(--gradient-hero);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.15rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 2rem;
    max-width: 500px;
}

.hero-stats {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem 1.5rem;
    text-align: center;
    min-width: 100px;
    transition: all var(--transition-base);
}

.stat-card:hover {
    border-color: var(--border-accent);
    box-shadow: var(--shadow-glow);
}

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

.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.hero-actions {
    display: flex;
    gap: 1rem;
}

.btn-arrow {
    transition: transform var(--transition-fast);
}
.btn-primary:hover .btn-arrow {
    transform: translateX(4px);
}

/* Code Preview Card */
.hero-visual {
    display: flex;
    justify-content: center;
}

.code-preview-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    width: 100%;
    max-width: 480px;
    box-shadow: var(--shadow-lg);
    animation: codeFloat 6s ease-in-out infinite;
}

@keyframes codeFloat {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.code-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: rgba(0, 0, 0, 0.3);
    border-bottom: 1px solid var(--border-color);
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}
.dot.red { background: #ff5f57; }
.dot.yellow { background: #febc2e; }
.dot.green { background: #28c840; }

.code-filename {
    margin-left: auto;
    font-size: 0.75rem;
    color: var(--text-muted);
    font-family: 'JetBrains Mono', monospace;
}

.code-body {
    padding: 1.5rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    line-height: 1.8;
    overflow-x: auto;
}

.code-body .tag { color: #ff79c6; }
.code-body .attr { color: #50fa7b; }
.code-body .value { color: #f1fa8c; }
.code-body .text { color: #f8f8f2; }
.code-body .comment { color: #6272a4; }

/* Study Plan */
.study-plan {
    padding: 3rem 0;
}

.plan-timeline {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
}

.plan-step {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    position: relative;
    transition: all var(--transition-base);
}

.plan-step:hover {
    border-color: var(--border-accent);
    transform: translateY(-4px);
    box-shadow: var(--shadow-glow);
}

.step-marker {
    width: 36px;
    height: 36px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.step-content h3 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.step-content p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* === Lessons === */
.lessons-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 2rem;
    min-height: 600px;
}

.lesson-sidebar {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1rem;
    height: fit-content;
    position: sticky;
    top: calc(var(--nav-height) + 2rem);
}

.sidebar-group {
    margin-bottom: 1rem;
}

.sidebar-group-title {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    font-weight: 700;
    padding: 0.5rem 0.75rem;
}

.lesson-nav-btn {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.6rem 0.75rem;
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-family: 'Inter', sans-serif;
    font-size: 0.82rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-align: left;
}

.lesson-nav-btn:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}

.lesson-nav-btn.active {
    background: rgba(108, 92, 231, 0.15);
    color: var(--accent-primary);
}

.lesson-nav-btn.completed {
    color: var(--accent-success);
}

.lesson-status {
    font-size: 0.7rem;
    flex-shrink: 0;
}

.lesson-content {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    line-height: 1.8;
}

.lesson-content h2 {
    font-size: 1.6rem;
    font-weight: 800;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.lesson-content h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin: 2rem 0 0.75rem;
    color: var(--accent-secondary);
}

.lesson-content p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.lesson-content .highlight {
    background: rgba(108, 92, 231, 0.1);
    border-left: 3px solid var(--accent-primary);
    padding: 1rem 1.25rem;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin: 1rem 0;
    font-size: 0.9rem;
}

.lesson-content .code-block {
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    margin: 1rem 0;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    line-height: 1.7;
    overflow-x: auto;
    white-space: pre;
}

.lesson-content .try-it {
    background: rgba(0, 206, 201, 0.08);
    border: 1px solid rgba(0, 206, 201, 0.2);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    margin: 1.5rem 0;
}

.lesson-content .try-it h4 {
    color: var(--accent-secondary);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.lesson-content .try-it p {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.lesson-nav-footer {
    display: flex;
    justify-content: space-between;
    margin-top: 2.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

/* === Code Playground === */
.playground-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    height: calc(100vh - var(--nav-height) - 180px);
    min-height: 500px;
}

.editor-panel {
    display: flex;
    flex-direction: column;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.editor-tabs {
    display: flex;
    background: rgba(0, 0, 0, 0.3);
    border-bottom: 1px solid var(--border-color);
}

.editor-tab {
    padding: 0.7rem 1.5rem;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    border-bottom: 2px solid transparent;
}

.editor-tab:hover {
    color: var(--text-primary);
}

.editor-tab.active {
    color: var(--accent-primary);
    border-bottom-color: var(--accent-primary);
    background: rgba(108, 92, 231, 0.05);
}

.editor-container {
    flex: 1;
    position: relative;
}

.code-editor {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    background: transparent;
    color: var(--text-primary);
    border: none;
    padding: 1.25rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    line-height: 1.7;
    resize: none;
    outline: none;
    tab-size: 2;
    display: none;
}

.code-editor.active {
    display: block;
}

.code-editor::placeholder {
    color: var(--text-muted);
}

.editor-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    background: rgba(0, 0, 0, 0.2);
    border-top: 1px solid var(--border-color);
}

.editor-templates {
    margin-left: auto;
}

.editor-templates select {
    background: var(--bg-card);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 0.4rem 0.75rem;
    border-radius: var(--radius-sm);
    font-family: 'Inter', sans-serif;
    font-size: 0.8rem;
    cursor: pointer;
    outline: none;
}

.preview-panel {
    display: flex;
    flex-direction: column;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.preview-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: rgba(0, 0, 0, 0.3);
    border-bottom: 1px solid var(--border-color);
}

.preview-title {
    margin-left: auto;
    font-size: 0.75rem;
    color: var(--text-muted);
    font-family: 'JetBrains Mono', monospace;
}

.preview-frame {
    flex: 1;
    border: none;
    background: white;
    width: 100%;
}

/* === Flashcards === */
.flashcard-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.fc-filter-group {
    display: flex;
    gap: 0.5rem;
}

.fc-filter {
    padding: 0.5rem 1.25rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 100px;
    color: var(--text-secondary);
    font-family: 'Inter', sans-serif;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.fc-filter:hover {
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-primary);
}

.fc-filter.active {
    background: rgba(108, 92, 231, 0.15);
    border-color: rgba(108, 92, 231, 0.4);
    color: var(--accent-primary);
}

.fc-progress {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.flashcard-deck {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 340px;
    perspective: 1000px;
}

.flashcard {
    width: 100%;
    max-width: 600px;
    height: 300px;
    cursor: pointer;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.flashcard.flipped {
    transform: rotateY(180deg);
}

.flashcard-face {
    position: absolute;
    inset: 0;
    backface-visibility: hidden;
    border-radius: var(--radius-xl);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 2.5rem;
    text-align: center;
}

.flashcard-front {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
}

.flashcard-front .fc-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--accent-primary);
    font-weight: 700;
    margin-bottom: 1.5rem;
    padding: 0.3rem 1rem;
    background: rgba(108, 92, 231, 0.1);
    border-radius: 100px;
}

.flashcard-front .fc-term {
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1.4;
}

.flashcard-front .fc-hint {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 2rem;
}

.flashcard-back {
    background: linear-gradient(135deg, #1a1f35, #222845);
    border: 1px solid var(--border-accent);
    box-shadow: var(--shadow-glow);
    transform: rotateY(180deg);
}

.flashcard-back .fc-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--accent-secondary);
    font-weight: 700;
    margin-bottom: 1rem;
    padding: 0.3rem 1rem;
    background: rgba(0, 206, 201, 0.1);
    border-radius: 100px;
}

.flashcard-back .fc-answer {
    font-size: 1.1rem;
    color: var(--text-primary);
    line-height: 1.6;
}

.flashcard-back .fc-code {
    background: rgba(0, 0, 0, 0.3);
    border-radius: var(--radius-sm);
    padding: 0.75rem 1rem;
    margin-top: 1rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    color: #a29bfe;
}

.flashcard-nav {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 2rem;
    margin-top: 1.5rem;
}

.fc-counter {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 600;
}

.fc-actions {
    display: flex;
    justify-content: center;
    gap: 0.75rem;
    margin-top: 1rem;
}

/* === Quiz === */
.quiz-start {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 50vh;
}

.quiz-start-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: 3rem 4rem;
    text-align: center;
    max-width: 500px;
}

.quiz-start-icon {
    font-size: 4rem;
    margin-bottom: 1.5rem;
}

.quiz-start-card h2 {
    font-size: 1.8rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
}

.quiz-start-card p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

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

.quiz-option-label {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
}

.quiz-option-label input[type="checkbox"] {
    accent-color: var(--accent-primary);
}

.quiz-progress-bar {
    width: 100%;
    height: 4px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 2px;
    margin-bottom: 0.75rem;
    overflow: hidden;
}

.quiz-progress-fill {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 2px;
    transition: width var(--transition-base);
    width: 0%;
}

.quiz-question-count {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-align: center;
    margin-bottom: 2rem;
    font-weight: 600;
}

.quiz-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: 2.5rem;
    max-width: 720px;
    margin: 0 auto;
}

.quiz-category {
    display: inline-block;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    font-weight: 700;
    padding: 0.3rem 0.85rem;
    border-radius: 100px;
    margin-bottom: 1.25rem;
}

.quiz-category[data-cat="HTML"] {
    background: rgba(253, 121, 168, 0.1);
    color: var(--accent-warm);
}

.quiz-category[data-cat="CSS"] {
    background: rgba(0, 206, 201, 0.1);
    color: var(--accent-secondary);
}

.quiz-question {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 1.25rem;
    line-height: 1.5;
}

.quiz-code {
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem 1.25rem;
    margin-bottom: 1.5rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    line-height: 1.6;
    white-space: pre;
    overflow-x: auto;
    display: none;
}

.quiz-code.visible {
    display: block;
}

.quiz-answers {
    display: grid;
    gap: 0.75rem;
}

.quiz-answer-btn {
    width: 100%;
    text-align: left;
    padding: 1rem 1.25rem;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: 'Inter', sans-serif;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.quiz-answer-btn:hover:not(.selected):not(.disabled) {
    background: rgba(255, 255, 255, 0.06);
    border-color: rgba(255, 255, 255, 0.15);
}

.quiz-answer-btn .answer-letter {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 50%;
    font-weight: 700;
    font-size: 0.8rem;
}

.quiz-answer-btn.correct {
    background: rgba(0, 184, 148, 0.12);
    border-color: rgba(0, 184, 148, 0.4);
    color: var(--accent-success);
}

.quiz-answer-btn.correct .answer-letter {
    background: var(--accent-success);
    color: white;
}

.quiz-answer-btn.wrong {
    background: rgba(225, 112, 85, 0.12);
    border-color: rgba(225, 112, 85, 0.4);
    color: var(--accent-error);
}

.quiz-answer-btn.wrong .answer-letter {
    background: var(--accent-error);
    color: white;
}

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

.quiz-feedback {
    margin-top: 1.5rem;
    padding: 1rem 1.25rem;
    border-radius: var(--radius-md);
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
}

.quiz-feedback.correct {
    background: rgba(0, 184, 148, 0.08);
    border: 1px solid rgba(0, 184, 148, 0.2);
}

.quiz-feedback.wrong {
    background: rgba(225, 112, 85, 0.08);
    border: 1px solid rgba(225, 112, 85, 0.2);
}

.feedback-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.feedback-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.quiz-nav {
    display: flex;
    justify-content: center;
    margin-top: 2rem;
}

/* Quiz Results */
.quiz-results {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 60vh;
}

.results-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: 3rem;
    text-align: center;
    max-width: 500px;
    width: 100%;
}

.results-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.results-title {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 2rem;
}

.results-score {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
}

.score-circle {
    width: 140px;
    height: 140px;
    position: relative;
}

.score-circle svg {
    width: 100%;
    height: 100%;
    transform: rotate(-90deg);
}

.score-bg {
    fill: none;
    stroke: rgba(255, 255, 255, 0.06);
    stroke-width: 3;
}

.score-fill {
    fill: none;
    stroke: var(--accent-primary);
    stroke-width: 3;
    stroke-linecap: round;
    transition: stroke-dasharray 1.5s ease;
}

.score-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 2rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.results-detail {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.results-breakdown {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-bottom: 2rem;
}

.breakdown-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.breakdown-count {
    font-size: 2rem;
    font-weight: 800;
}

.breakdown-item.correct .breakdown-count { color: var(--accent-success); }
.breakdown-item.wrong .breakdown-count { color: var(--accent-error); }

.breakdown-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

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

/* Quiz Review */
.review-title {
    font-size: 1.5rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
}

.review-item {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    margin-bottom: 1rem;
}

.review-item.review-correct {
    border-left: 3px solid var(--accent-success);
}

.review-item.review-wrong {
    border-left: 3px solid var(--accent-error);
}

.review-item h4 {
    font-size: 0.95rem;
    margin-bottom: 0.5rem;
}

.review-item .review-answer {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.review-item .review-answer strong {
    color: var(--accent-success);
}

.review-item .review-answer .your-answer {
    color: var(--accent-error);
}

/* === Cheat Sheet === */
.cheatsheet-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
    justify-content: center;
}

.cs-tab {
    padding: 0.6rem 1.5rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 100px;
    color: var(--text-secondary);
    font-family: 'Inter', sans-serif;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.cs-tab:hover {
    background: rgba(255, 255, 255, 0.08);
}

.cs-tab.active {
    background: var(--gradient-primary);
    border-color: transparent;
    color: white;
}

.cheatsheet-content {
    display: none;
}

.cheatsheet-content.active {
    display: block;
}

.cs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 1.25rem;
}

.cs-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    transition: all var(--transition-base);
}

.cs-card:hover {
    border-color: var(--border-accent);
    box-shadow: var(--shadow-glow);
    transform: translateY(-2px);
}

.cs-card h3 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.cs-card pre {
    background: rgba(0, 0, 0, 0.3);
    border-radius: var(--radius-sm);
    padding: 1rem;
    overflow-x: auto;
}

.cs-card code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    line-height: 1.7;
    color: #a29bfe;
}

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

/* === Responsive === */
@media (max-width: 1024px) {
    .hero {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
        min-height: auto;
    }

    .hero-subtitle {
        max-width: none;
    }

    .hero-stats {
        justify-content: center;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-visual {
        order: -1;
    }

    .plan-timeline {
        grid-template-columns: repeat(2, 1fr);
    }

    .lessons-layout {
        grid-template-columns: 1fr;
    }

    .lesson-sidebar {
        position: static;
    }

    .playground-layout {
        grid-template-columns: 1fr;
        height: auto;
    }

    .editor-panel, .preview-panel {
        min-height: 400px;
    }

    .nav-label {
        display: none;
    }

    .nav-btn {
        padding: 0.5rem;
    }
}

@media (max-width: 640px) {
    .section {
        padding: 1.5rem 1rem;
    }

    .hero-title {
        font-size: 2.25rem;
    }

    .hero-stats {
        flex-wrap: wrap;
    }

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

    .plan-timeline {
        grid-template-columns: 1fr;
    }

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

    .quiz-start-card {
        padding: 2rem;
    }

    .quiz-card {
        padding: 1.5rem;
    }

    .flashcard {
        height: 260px;
    }
}