/* CSS Variables */
:root {
    /* Light theme */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border-color: #e2e8f0;
    --accent-primary: #7c3aed;
    --accent-secondary: #a78bfa;
    --accent-light: #ede9fe;
    --success: #22c55e;
    --warning: #f59e0b;
    --error: #ef4444;
    /* Dracula theme */
    --code-bg: #282a36;
    --code-text: #f8f8f2;
    --code-line: #44475a;
    --code-comment: #6272a4;
    --code-string: #f1fa8c;
    --code-command: #50fa7b;
    --code-flag: #ffb86c;
    --code-var: #ff79c6;
    --code-number: #bd93f9;
    --code-key: #8be9fd;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
}

/* Dark theme */
[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
    --border-color: #334155;
    --accent-light: #2e1065;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Header */
.header {
    position: sticky;
    top: 0;
    z-index: 100;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    backdrop-filter: blur(10px);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
    gap: 2rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--accent-primary);
}

.logo-icon {
    font-size: 1.5rem;
}

.nav {
    display: flex;
    gap: 1.5rem;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.nav-link:hover {
    color: var(--accent-primary);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

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

.search-input {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 0.875rem;
    width: 200px;
    transition: all var(--transition-fast);
}

.search-input:focus {
    outline: none;
    border-color: var(--accent-primary);
    width: 280px;
}

.search-results {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    margin-top: 0.5rem;
    max-height: 300px;
    overflow-y: auto;
    display: none;
    box-shadow: var(--shadow-lg);
}

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

.search-result-item {
    padding: 0.75rem 1rem;
    cursor: pointer;
    border-bottom: 1px solid var(--border-color);
}

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

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

.search-result-title {
    font-weight: 600;
    color: var(--text-primary);
}

.search-result-module {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Theme Toggle */
.theme-toggle {
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    transition: all var(--transition-fast);
}

.theme-toggle:hover {
    background-color: var(--bg-secondary);
}

.sun-icon, .moon-icon {
    font-size: 1.25rem;
}

.moon-icon {
    display: none;
}

[data-theme="dark"] .sun-icon {
    display: none;
}

[data-theme="dark"] .moon-icon {
    display: block;
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    text-align: center;
    background: linear-gradient(135deg, var(--accent-light) 0%, var(--bg-primary) 100%);
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 2rem;
}

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

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent-primary);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    font-size: 1rem;
}

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

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

.btn-secondary {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: var(--bg-tertiary);
}

/* Progress Section */
.progress-section {
    padding: 3rem 0;
    background-color: var(--bg-secondary);
}

.section-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    text-align: center;
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-top: -1rem;
    margin-bottom: 1.5rem;
}

.progress-overview {
    display: flex;
    align-items: center;
    gap: 1rem;
    max-width: 600px;
    margin: 0 auto 1.5rem;
}

.progress-bar-container {
    flex: 1;
    height: 12px;
    background-color: var(--bg-tertiary);
    border-radius: 6px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
    border-radius: 6px;
    width: 0%;
    transition: width var(--transition-normal);
}

.progress-text {
    font-weight: 600;
    color: var(--accent-primary);
    min-width: 120px;
    text-align: right;
}

.level-badges {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.badge {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-weight: 500;
    font-size: 0.875rem;
    opacity: 0.5;
    transition: all var(--transition-fast);
}

.badge.unlocked {
    opacity: 1;
    transform: scale(1.05);
}

.badge-beginner {
    background-color: #dcfce7;
    color: #166534;
}

.badge-intermediate {
    background-color: #dbeafe;
    color: #1e40af;
}

.badge-advanced {
    background-color: #fee2e2;
    color: #991b1b;
}

[data-theme="dark"] .badge-beginner {
    background-color: #14532d;
    color: #86efac;
}

[data-theme="dark"] .badge-intermediate {
    background-color: #1e3a5f;
    color: #93c5fd;
}

[data-theme="dark"] .badge-advanced {
    background-color: #450a0a;
    color: #fca5a5;
}

/* Roadmap Section */
.roadmap-section {
    padding: 3rem 0;
}

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

.roadmap-level {
    background-color: var(--bg-secondary);
    border-radius: 1rem;
    padding: 1.5rem;
    margin-bottom: 0.5rem;
}

.level-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.level-beginner {
    color: #22c55e;
}

.level-intermediate {
    color: #3b82f6;
}

.level-advanced {
    color: #ef4444;
}

.roadmap-items {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.roadmap-item {
    background-color: var(--bg-primary);
    padding: 0.75rem 1.25rem;
    border-radius: 0.5rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
}

.roadmap-arrow {
    color: var(--text-muted);
    font-size: 1.25rem;
}

.roadmap-connector {
    text-align: center;
    font-size: 1.5rem;
    color: var(--text-muted);
    padding: 0.5rem 0;
}

/* Modules Section */
.modules-section {
    padding: 3rem 0;
}

.module {
    background-color: var(--bg-secondary);
    border-radius: 1rem;
    margin-bottom: 1rem;
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.module-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.25rem 1.5rem;
    cursor: pointer;
    transition: background-color var(--transition-fast);
}

.module-header:hover {
    background-color: var(--bg-tertiary);
}

.module-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.module-number {
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--accent-primary);
    background-color: var(--accent-light);
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
}

.module-title {
    font-size: 1.125rem;
    font-weight: 600;
}

.module-level {
    font-size: 0.75rem;
    font-weight: 600;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    text-transform: uppercase;
}

.module-level.beginner {
    background-color: #dcfce7;
    color: #166534;
}

.module-level.intermediate {
    background-color: #dbeafe;
    color: #1e40af;
}

.module-level.advanced {
    background-color: #fee2e2;
    color: #991b1b;
}

[data-theme="dark"] .module-level.beginner {
    background-color: #14532d;
    color: #86efac;
}

[data-theme="dark"] .module-level.intermediate {
    background-color: #1e3a5f;
    color: #93c5fd;
}

[data-theme="dark"] .module-level.advanced {
    background-color: #450a0a;
    color: #fca5a5;
}

.module-time {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.module-status {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.module-checkbox {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--accent-primary);
}

.expand-icon {
    transition: transform var(--transition-fast);
    color: var(--text-muted);
}

.module.expanded .expand-icon {
    transform: rotate(180deg);
}

.module-content {
    display: none;
    padding: 0 1.5rem 1.5rem;
    border-top: 1px solid var(--border-color);
}

.module.expanded .module-content {
    display: block;
}

.module-description {
    padding: 1.5rem 0;
}

.module-description h4 {
    font-size: 1rem;
    font-weight: 600;
    margin: 1.5rem 0 0.75rem;
    color: var(--accent-primary);
}

.module-description h4:first-child {
    margin-top: 0;
}

.module-description ul {
    padding-left: 1.5rem;
}

.module-description li {
    margin-bottom: 0.5rem;
}

.module-description ol {
    padding-left: 1.5rem;
}

.module-description ol li {
    margin-bottom: 0.25rem;
}

blockquote {
    border-left: 4px solid var(--accent-primary);
    background-color: var(--accent-light);
    padding: 0.75rem 1rem;
    border-radius: 0 0.5rem 0.5rem 0;
    margin: 1rem 0;
    color: var(--text-secondary);
}

/* Command Table */
.command-table {
    background-color: var(--bg-primary);
    border-radius: 0.5rem;
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.command-row {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-color);
    gap: 1rem;
}

.command-row:last-child {
    border-bottom: none;
}

.command-row code {
    background-color: var(--code-bg);
    color: var(--code-command);
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.875rem;
    min-width: 180px;
}

.command-row span {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Memory Hierarchy */
.memory-hierarchy {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.memory-level {
    display: grid;
    grid-template-columns: 150px 1fr auto;
    gap: 1rem;
    align-items: center;
    padding: 0.75rem 1rem;
    background-color: var(--bg-primary);
    border-radius: 0.5rem;
    border: 1px solid var(--border-color);
}

.memory-level strong {
    color: var(--accent-primary);
}

.memory-level code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.memory-level span {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* Exercises */
.exercises {
    padding: 1.5rem 0;
    border-top: 1px solid var(--border-color);
}

.exercises h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--accent-primary);
}

.exercise {
    background-color: var(--bg-primary);
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.exercise-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem;
    cursor: pointer;
}

.exercise-checkbox {
    width: 18px;
    height: 18px;
    accent-color: var(--success);
}

.exercise-title {
    font-weight: 500;
}

.exercise-content {
    padding: 0 1rem 1rem;
}

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

/* Code blocks */
pre {
    background-color: var(--code-bg);
    border: 1px solid var(--code-line);
    border-radius: 0.5rem;
    padding: 1rem;
    overflow-x: auto;
    margin: 1rem 0;
}

pre code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.875rem;
    color: var(--code-text);
    background-color: transparent;
    padding: 0;
    border-radius: 0;
    line-height: 1.5;
}

code {
    font-family: 'JetBrains Mono', monospace;
    background-color: var(--bg-tertiary);
    padding: 0.125rem 0.375rem;
    border-radius: 0.25rem;
    font-size: 0.875rem;
}

/* Syntax highlighting — Dracula palette */
.tok-comment { color: var(--code-comment); font-style: italic; }
.tok-string  { color: var(--code-string); }
.tok-command { color: var(--code-command); font-weight: 600; }
.tok-flag    { color: var(--code-flag); }
.tok-var     { color: var(--code-var); }
.tok-number  { color: var(--code-number); }
.tok-key     { color: var(--code-key); }
.tok-keyword { color: var(--code-var); font-weight: 600; }
.tok-header  { color: var(--code-var); font-weight: 700; }

/* Quiz Section */
.quiz-section {
    padding: 1.5rem 0;
    border-top: 1px solid var(--border-color);
}

.quiz-section h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--accent-primary);
}

.quiz {
    background-color: var(--bg-primary);
    border-radius: 0.5rem;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
}

.quiz-question {
    margin-bottom: 1.5rem;
}

.quiz-question p {
    font-weight: 500;
    margin-bottom: 0.75rem;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.quiz-options label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.75rem;
    background-color: var(--bg-secondary);
    border-radius: 0.375rem;
    cursor: pointer;
    transition: background-color var(--transition-fast);
}

.quiz-options label:hover {
    background-color: var(--bg-tertiary);
}

.quiz-options input[type="radio"] {
    accent-color: var(--accent-primary);
}

.quiz-result {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 0.5rem;
    font-weight: 500;
    display: none;
}

.quiz-result.show {
    display: block;
}

.quiz-result.correct {
    background-color: #dcfce7;
    color: #166534;
}

.quiz-result.incorrect {
    background-color: #fee2e2;
    color: #991b1b;
}

[data-theme="dark"] .quiz-result.correct {
    background-color: #14532d;
    color: #86efac;
}

[data-theme="dark"] .quiz-result.incorrect {
    background-color: #450a0a;
    color: #fca5a5;
}

/* Quick Reference */
.quick-ref-section {
    padding: 3rem 0;
    background-color: var(--bg-secondary);
}

.quick-ref-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.quick-ref-card {
    background-color: var(--bg-primary);
    padding: 1.5rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
}

.quick-ref-card h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--accent-primary);
}

.quick-ref-card code {
    display: inline-block;
    margin-right: 0.5rem;
}

/* Footer */
.footer {
    padding: 2rem 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

.footer p {
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
}

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

.footer a:hover {
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
    .header-content {
        flex-wrap: wrap;
        gap: 1rem;
    }
    
    .nav {
        order: 3;
        width: 100%;
        justify-content: center;
    }
    
    .search-input {
        width: 150px;
    }
    
    .search-input:focus {
        width: 200px;
    }
    
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-stats {
        gap: 1.5rem;
    }
    
    .stat-number {
        font-size: 1.5rem;
    }
    
    .module-info {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
    
    .command-row {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .command-row code {
        min-width: auto;
    }
    
    .memory-level {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    .roadmap-items {
        flex-direction: column;
    }
    
    .roadmap-arrow {
        transform: rotate(90deg);
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .hero-title {
        font-size: 1.5rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .level-badges {
        flex-direction: column;
        align-items: center;
    }
}

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

.module-content {
    animation: fadeIn 0.3s ease;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

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

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

/* Print styles */
@media print {
    .header,
    .theme-toggle,
    .search-container,
    .module-checkbox,
    .exercise-checkbox,
    .quiz-section,
    .footer {
        display: none;
    }
    
    .module-content {
        display: block !important;
    }
    
    body {
        background: white;
        color: black;
    }
}