/* ==========================================================================
   WebsiteLearn - Core Styles
   ========================================================================== */

:root {
    --bg-primary: #0f1117;
    --bg-secondary: #171923;
    --bg-tertiary: #1e2230;
    --bg-elevated: #262b3d;
    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --border: #2d3345;
    --primary: #6366f1;
    --primary-hover: #818cf8;
    --primary-dim: rgba(99, 102, 241, 0.15);
    --success: #34d399;
    --warning: #fbbf24;
    --danger: #f87171;
    --js-color: #f7df1e;
    --html-color: #e34f26;
    --css-color: #2965f1;
    --radius-sm: 6px;
    --radius: 10px;
    --radius-lg: 16px;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.35);
    --font-mono: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', Consolas, 'Courier New', monospace;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --transition: all 0.2s ease;
}

[data-theme="light"] {
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f1f5f9;
    --bg-elevated: #e2e8f0;
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border: #e2e8f0;
    --primary: #4f46e5;
    --primary-hover: #6366f1;
    --primary-dim: rgba(99, 102, 241, 0.1);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.1);
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
    text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background 0.3s ease, color 0.3s ease;
}

main {
    flex: 1;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

a {
    color: var(--primary);
    text-decoration: none;
}

a:hover {
    color: var(--primary-hover);
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: var(--radius);
    border: 1px solid transparent;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
    white-space: nowrap;
}

.btn:active {
    transform: scale(0.97);
}

.btn-primary {
    background: var(--primary);
    color: #ffffff;
    border-color: var(--primary);
}

.btn-primary:hover {
    background: var(--primary-hover);
    color: #ffffff;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.35);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border-color: var(--border);
}

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

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

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

.btn-large {
    padding: 14px 28px;
    font-size: 1.05rem;
    border-radius: var(--radius-lg);
}

.btn-sm {
    padding: 6px 14px;
    font-size: 0.875rem;
    border-radius: var(--radius-sm);
}

/* ==========================================================================
   Header / Navigation
   ========================================================================== */

.header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(12px);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    gap: 20px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
}

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

.nav-links {
    display: flex;
    align-items: center;
    gap: 4px;
    flex: 1;
    justify-content: center;
}

.nav-link {
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 500;
    padding: 8px 14px;
    border-radius: var(--radius);
    transition: var(--transition);
}

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

.nav-link.active {
    color: var(--primary);
    background: var(--primary-dim);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

/* Search */
.search-container {
    position: relative;
}

.search-icon {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    pointer-events: none;
}

.search-input {
    width: 220px;
    padding: 8px 14px 8px 38px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: 0.9rem;
    outline: none;
    transition: var(--transition);
}

.search-input:focus {
    border-color: var(--primary);
    width: 260px;
    box-shadow: 0 0 0 3px var(--primary-dim);
}

.search-input::placeholder {
    color: var(--text-muted);
}

.search-results {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    right: 0;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    display: none;
    z-index: 100;
    max-height: 360px;
    overflow-y: auto;
}

.search-results.show {
    display: block;
}

.search-result-item {
    display: block;
    padding: 12px 16px;
    border-bottom: 1px solid var(--border);
    cursor: pointer;
    color: var(--text-primary);
    transition: var(--transition);
}

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

.search-result-item:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.search-result-title {
    font-weight: 500;
    font-size: 0.9rem;
}

.search-result-cat {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-top: 2px;
}

.search-no-results {
    padding: 16px;
    color: var(--text-muted);
    font-size: 0.9rem;
    text-align: center;
}

/* Theme toggle */
.theme-toggle {
    background: transparent;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 8px;
    cursor: pointer;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.theme-toggle:hover {
    color: var(--primary);
    border-color: var(--primary);
}

.theme-toggle .sun-icon {
    display: none;
}

.theme-toggle .moon-icon {
    display: block;
}

[data-theme="light"] .theme-toggle .sun-icon {
    display: block;
}

[data-theme="light"] .theme-toggle .moon-icon {
    display: none;
}

/* Hamburger */
.hamburger {
    display: none;
    background: transparent;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 8px;
    cursor: pointer;
    flex-direction: column;
    gap: 5px;
    align-items: center;
    justify-content: center;
}

.hamburger span {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

.hamburger.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ==========================================================================
   Hero
   ========================================================================== */

.hero {
    padding: 80px 0 60px;
    text-align: center;
    background: linear-gradient(180deg, var(--primary-dim) 0%, transparent 60%);
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary-hover), var(--js-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 16px;
    letter-spacing: -1px;
}

.hero-subtitle {
    font-size: 1.35rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 36px;
    line-height: 1.5;
}

.hero-buttons {
    display: flex;
    gap: 14px;
    justify-content: center;
    flex-wrap: wrap;
}

/* ==========================================================================
   Section titles
   ========================================================================== */

.section-title {
    font-size: 1.9rem;
    font-weight: 700;
    margin-bottom: 32px;
    text-align: center;
}

/* ==========================================================================
   Learning paths
   ========================================================================== */

.paths {
    padding: 60px 0;
}

.path-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.path-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px;
    position: relative;
    transition: var(--transition);
}

.path-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.path-card.featured {
    border-color: var(--js-color);
    background: linear-gradient(160deg, var(--primary-dim) 0%, var(--bg-secondary) 100%);
}

.path-badge {
    position: absolute;
    top: -12px;
    right: 20px;
    background: var(--js-color);
    color: #1a1a1a;
    font-size: 0.75rem;
    font-weight: 700;
    padding: 4px 12px;
    border-radius: 20px;
    letter-spacing: 0.5px;
}

.path-icon {
    width: 64px;
    height: 64px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.html-card .path-icon {
    background: rgba(227, 79, 38, 0.15);
    color: var(--html-color);
}

.css-card .path-icon {
    background: rgba(41, 101, 241, 0.15);
    color: var(--css-color);
}

.js-card .path-icon {
    background: rgba(247, 223, 30, 0.15);
    color: var(--js-color);
}

.path-card h3 {
    font-size: 1.4rem;
    margin-bottom: 12px;
}

.path-card p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    min-height: 72px;
}

.path-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
}

.path-link:hover svg {
    transform: translateX(3px);
}

.path-link svg {
    transition: transform 0.2s ease;
}

/* ==========================================================================
   Features
   ========================================================================== */

.features {
    padding: 60px 0;
    background: var(--bg-secondary);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
}

.feature {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    text-align: center;
}

.feature-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius);
    background: var(--primary-dim);
    color: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
}

.feature h3 {
    font-size: 1.1rem;
    margin-bottom: 8px;
}

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

/* ==========================================================================
   Footer
   ========================================================================== */

.footer {
    border-top: 1px solid var(--border);
    padding: 24px 0;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: auto;
}

/* ==========================================================================
   Learn page
   ========================================================================== */

.learn-page, .practice-page, .projects-page {
    padding: 40px 0 60px;
}

.page-title {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.page-sub {
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-bottom: 32px;
}

.path-tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 32px;
    flex-wrap: wrap;
}

.path-tab {
    padding: 10px 20px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    background: var(--bg-secondary);
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.path-tab:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.path-tab.active {
    background: var(--primary);
    color: #ffffff;
    border-color: var(--primary);
}

/* Lesson cards grid */
.lesson-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.lesson-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    transition: var(--transition);
    display: block;
    color: var(--text-primary);
}

.lesson-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    border-color: var(--primary);
    color: var(--text-primary);
}

.lesson-card-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
}

.lesson-category {
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    padding: 4px 10px;
    border-radius: 20px;
}

.lesson-category.html {
    background: rgba(227, 79, 38, 0.15);
    color: var(--html-color);
}

.lesson-category.css {
    background: rgba(41, 101, 241, 0.15);
    color: var(--css-color);
}

.lesson-category.js {
    background: rgba(247, 223, 30, 0.15);
    color: var(--js-color);
}

.lesson-status {
    color: var(--success);
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 0.8rem;
    font-weight: 500;
}

.lesson-card h3 {
    font-size: 1.15rem;
    margin-bottom: 8px;
}

.lesson-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 12px;
}

/* ==========================================================================
   Lesson page
   ========================================================================== */

.lesson-layout {
    display: flex;
    min-height: calc(100vh - 64px);
}

.lesson-sidebar {
    width: 280px;
    flex-shrink: 0;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border);
    overflow-y: auto;
    padding: 20px 0;
    position: sticky;
    top: 64px;
    height: calc(100vh - 64px);
    transition: transform 0.3s ease;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px 16px;
    border-bottom: 1px solid var(--border);
    margin-bottom: 12px;
}

.sidebar-header h3 {
    font-size: 0.78rem;
    letter-spacing: 1.5px;
    color: var(--text-muted);
    font-weight: 700;
}

.sidebar-close {
    display: none;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0 4px;
}

.sidebar-section {
    margin-bottom: 12px;
}

.sidebar-section-title {
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 1px;
    text-transform: uppercase;
    color: var(--text-muted);
    padding: 8px 20px;
}

.sidebar-section-title.js {
    color: var(--js-color);
}

.sidebar-section-title.html {
    color: var(--html-color);
}

.sidebar-section-title.css {
    color: var(--css-color);
}

.sidebar-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
    border-left: 3px solid transparent;
    transition: var(--transition);
}

.sidebar-item:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.sidebar-item.active {
    background: var(--primary-dim);
    color: var(--primary);
    border-left-color: var(--primary);
}

.sidebar-item .done-icon {
    color: var(--success);
    margin-left: auto;
    flex-shrink: 0;
}

/* sidebar toggle button shown on mobile */
.sidebar-toggle {
    display: none;
    position: fixed;
    bottom: 20px;
    left: 20px;
    z-index: 900;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--primary);
    color: #ffffff;
    border: none;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    align-items: center;
    justify-content: center;
}

/* Lesson content */
.lesson-content {
    flex: 1;
    padding: 40px;
    max-width: 860px;
    margin: 0 auto;
}

.lesson-loading {
    text-align: center;
    color: var(--text-muted);
    padding: 60px;
}

.lesson-cat {
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    display: inline-block;
    padding: 4px 12px;
    border-radius: 20px;
    margin-bottom: 16px;
}

.lesson-cat.html {
    background: rgba(227, 79, 38, 0.15);
    color: var(--html-color);
}

.lesson-cat.css {
    background: rgba(41, 101, 241, 0.15);
    color: var(--css-color);
}

.lesson-cat.js {
    background: rgba(247, 223, 30, 0.15);
    color: var(--js-color);
}

.lesson-title {
    font-size: 2.2rem;
    font-weight: 800;
    margin-bottom: 20px;
    letter-spacing: -0.5px;
}

.lesson-body {
    font-size: 1.02rem;
    color: var(--text-primary);
    overflow-wrap: break-word;
    word-break: break-word;
}

.lesson-body img,
.lesson-body video,
.lesson-body iframe,
.lesson-body table {
    max-width: 100%;
}

.lesson-body table {
    display: block;
    overflow-x: auto;
}

.lesson-body h3 {
    font-size: 1.35rem;
    margin: 32px 0 12px;
}

.lesson-body p {
    margin-bottom: 16px;
}

.lesson-body ul, .lesson-body ol {
    margin: 0 0 16px 24px;
}

.lesson-body li {
    margin-bottom: 6px;
}

.lesson-body strong {
    color: var(--text-primary);
}

.code-block {
    background: #0d1117;
    border: 1px solid #1f2937;
    border-radius: var(--radius);
    padding: 16px;
    overflow-x: auto;
    font-family: var(--font-mono);
    font-size: 0.9rem;
    line-height: 1.6;
    margin: 16px 0 20px;
    position: relative;
}

[data-theme="light"] .code-block {
    background: #1a1d23;
    color: #d4d4d8;
}

.code-block pre {
    font-family: var(--font-mono);
    white-space: pre;
}

.code-block .lang-label {
    position: absolute;
    top: 8px;
    right: 12px;
    font-size: 0.7rem;
    color: #6b7280;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Interactive example area */
.lesson-demo {
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin: 24px 0;
    background: var(--bg-secondary);
}

.lesson-demo .demo-title {
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.lesson-demo .demo-content {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.demo-buttons {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.demo-target {
    padding: 16px;
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    color: var(--text-secondary);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    min-height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Lesson embedded playground */
.lesson-playground {
    margin-top: 24px;
}

.lesson-playground .editor-wrapper {
    min-height: 180px;
}

/* Challenge */
.challenge-block {
    background: linear-gradient(145deg, var(--primary-dim) 0%, var(--bg-secondary) 100%);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    margin-top: 40px;
}

.challenge-block h3 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.2rem;
    margin-bottom: 12px;
}

.challenge-task {
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.challenge-block .editor-wrapper {
    min-height: 160px;
}

.challenge-result {
    margin-top: 16px;
    padding: 14px;
    border-radius: var(--radius);
    display: none;
}

.challenge-result.success {
    display: block;
    background: rgba(52, 211, 153, 0.1);
    border: 1px solid var(--success);
    color: var(--success);
}

.challenge-result.fail {
    display: block;
    background: rgba(248, 113, 113, 0.1);
    border: 1px solid var(--danger);
    color: var(--danger);
}

.challenge-result .challenge-msg {
    font-size: 0.95rem;
}

.challenge-result .challenge-hint {
    font-size: 0.85rem;
    margin-top: 6px;
    opacity: 0.8;
}

/* Lesson navigation */
.lesson-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 48px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
    gap: 12px;
}

.lesson-nav-arrow {
    display: inline-flex;
    flex-direction: column;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: var(--transition);
    color: var(--text-secondary);
    cursor: pointer;
    background: var(--bg-secondary);
}

.lesson-nav-arrow:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.lesson-nav-arrow.next {
    text-align: right;
    align-items: flex-end;
}

.lesson-nav-arrow.disabled {
    opacity: 0.4;
    pointer-events: none;
}

.lesson-nav-arrow .nav-dir {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.lesson-nav-arrow .nav-title {
    font-size: 0.95rem;
    font-weight: 500;
    margin-top: 2px;
}

/* Mark complete */
.mark-complete {
    margin-top: 16px;
}

/* ==========================================================================
   Playground / Editor
   ========================================================================== */

.playground {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0;
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin-bottom: 48px;
}

.playground {
    grid-template-columns: 3fr 2fr;
}

.editor-panel {
    border-right: 1px solid var(--border);
}

.panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 20px;
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border);
}

.panel-header h2 {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    letter-spacing: 0.3px;
}

.panel-actions {
    display: flex;
    gap: 8px;
}

.editor-wrapper {
    display: flex;
    background: #0d1117;
    min-height: 320px;
    font-family: var(--font-mono);
}

.line-numbers {
    padding: 16px 10px;
    color: #4b5563;
    font-size: 0.875rem;
    line-height: 1.55;
    text-align: right;
    user-select: none;
    background: #0d1117;
    min-width: 40px;
    border-right: 1px solid #1f2937;
    font-family: var(--font-mono);
}

#codeEditor, .lesson-editor-textarea {
    flex: 1;
    background: transparent;
    border: none;
    color: #d1d5db;
    padding: 16px;
    font-family: var(--font-mono);
    font-size: 0.875rem;
    line-height: 1.55;
    resize: vertical;
    outline: none;
    min-height: 320px;
    tab-size: 4;
    white-space: pre;
    overflow-wrap: normal;
    overflow-x: auto;
}

.lesson-demo textarea {
    min-height: 180px;
}

.output-panel {
    background: var(--bg-secondary);
    display: flex;
    flex-direction: column;
}

.console-output {
    flex: 1;
    padding: 16px 20px;
    font-family: var(--font-mono);
    font-size: 0.875rem;
    overflow-y: auto;
    max-height: 400px;
    min-height: 320px;
}

.console-line {
    padding: 4px 0;
    border-bottom: 1px solid rgba(128, 128, 128, 0.08);
    white-space: pre-wrap;
    word-break: break-word;
}

.console-line.log {
    color: #d1d5db;
}

.console-line.log-value {
    color: #7edf7e;
}

.console-line.error {
    color: var(--danger);
}

.console-line.warn {
    color: var(--warning);
}

.console-line.info {
    color: #60a5fa;
}

.console-empty {
    color: var(--text-muted);
    font-style: italic;
    text-align: center;
    padding: 40px 0;
}

/* ==========================================================================
   Challenges
   ========================================================================== */

.challenges-section {
    padding-top: 8px;
}

.challenge-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 20px;
}

.challenge-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
}

.challenge-card .challenge-title {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
}

.challenge-card h3 {
    font-size: 1.05rem;
}

.challenge-done {
    color: var(--success);
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 0.8rem;
}

.challenge-task {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 16px;
}

.challenge-card .editor-wrapper {
    min-height: 140px;
}

.challenge-card textarea {
    min-height: 140px;
}

.challenge-card .challenge-actions {
    display: flex;
    gap: 8px;
    margin-top: 12px;
}

.challenge-feedback {
    margin-top: 10px;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.challenge-feedback.pass {
    color: var(--success);
}

.challenge-feedback.fail {
    color: var(--danger);
}

/* ==========================================================================
   Projects
   ========================================================================== */

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

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

.project-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.project-preview {
    height: 160px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 8px;
    position: relative;
    overflow: hidden;
}

.project-preview .preview-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-preview .preview-inner {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 700;
}

.project-card .project-info {
    padding: 20px;
    display: flex;
    flex-direction: column;
    flex: 1;
}

.project-card h3 {
    font-size: 1.15rem;
    margin-bottom: 8px;
}

.project-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 16px;
    flex: 1;
}

.project-card .project-actions {
    display: flex;
    gap: 8px;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 16px;
}

.project-tag {
    font-size: 0.7rem;
    padding: 3px 10px;
    border-radius: 20px;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border: 1px solid var(--border);
}

/* Live project demos */
.project-demo {
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px;
    margin: 24px 0;
    background: var(--bg-secondary);
    text-align: center;
}

.project-demo .demo-title {
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-muted);
    margin-bottom: 20px;
}

.project-demo .demo-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

.counter-display {
    font-size: 3.5rem;
    font-weight: 800;
    font-family: var(--font-mono);
    color: var(--primary);
}

.step-display {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

/* Todo demo */
.todo-input-row {
    display: flex;
    gap: 8px;
    width: 100%;
    max-width: 400px;
}

.todo-input-row input {
    flex: 1;
    padding: 10px 14px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    outline: none;
    font-family: var(--font-sans);
}

.todo-input-row input:focus {
    border-color: var(--primary);
}

.todo-list {
    width: 100%;
    max-width: 400px;
    list-style: none;
    text-align: left;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.todo-list li {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding: 10px 14px;
    background: var(--bg-tertiary);
    border-radius: var(--radius);
}

.todo-list li.completed span {
    text-decoration: line-through;
    color: var(--text-muted);
}

.todo-list .todo-actions {
    display: flex;
    gap: 6px;
}

.todo-list button {
    background: transparent;
    border: none;
    cursor: pointer;
    color: var(--text-muted);
    font-size: 0.8rem;
    padding: 4px;
    border-radius: 4px;
}

.todo-list button:hover {
    color: var(--danger);
}

/* Quiz */
.quiz-question {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
    width: 100%;
    max-width: 400px;
}

.quiz-option {
    padding: 12px 16px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    cursor: pointer;
    text-align: left;
    transition: var(--transition);
    font-family: var(--font-sans);
    font-size: 0.95rem;
}

.quiz-option:hover {
    border-color: var(--primary);
}

.quiz-option.correct {
    background: rgba(52, 211, 153, 0.15);
    border-color: var(--success);
    color: var(--success);
}

.quiz-option.wrong {
    background: rgba(248, 113, 113, 0.15);
    border-color: var(--danger);
    color: var(--danger);
}

.quiz-score {
    font-size: 1rem;
    color: var(--text-secondary);
    font-family: var(--font-mono);
}

.quiz-result-done {
    font-size: 1.2rem;
    color: var(--success);
    font-weight: 600;
}

/* ==========================================================================
   Scrollbar
   ========================================================================== */

::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* ==========================================================================
   Project demo modal
   ========================================================================== */

.project-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.6);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.project-modal-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    max-width: 720px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
}

.project-modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 18px 24px;
    border-bottom: 1px solid var(--border);
}

.project-modal-header h3 {
    font-size: 1.2rem;
}

.project-modal-body {
    padding: 28px 24px;
}

.project-modal-code {
    border-top: 1px solid var(--border);
}

.project-modal-code .panel-header {
    border-bottom: 1px solid var(--border);
}

/* ==========================================================================
   Utility
   ========================================================================== */

.hidden {
    display: none !important;
}

/* Fade-in animation for lessons */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(12px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-in {
    animation: fadeInUp 0.4s ease forwards;
}

/* Progress bar */
.progress-bar {
    height: 6px;
    background: var(--bg-tertiary);
    border-radius: 3px;
    overflow: hidden;
    margin-top: 12px;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--success));
    border-radius: 3px;
    transition: width 0.5s ease;
}

.progress-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 6px;
}

.progress-label .percent {
    font-weight: 700;
    color: var(--primary);
}