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

:root {
    --bg-primary: #0a0a0a;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #2a2a2a;
    --text-primary: #e0e0e0;
    --text-secondary: #a0a0a0;
    --accent: #4a9eff;
    --accent-hover: #6bb0ff;
    --border: #333;
    --success: #4ade80;
    --warning: #fbbf24;
    --error: #f87171;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

header {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    padding: 2rem;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    color: var(--accent);
}

header h1 a {
    color: inherit;
    text-decoration: none;
    transition: opacity 0.2s ease;
}

header h1 a:hover {
    opacity: 0.8;
    cursor: pointer;
}

.tagline {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-style: italic;
}

main {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
}

.intro {
    text-align: center;
    margin: -2.5rem 0 3rem 0;
    padding: 2rem;
}

.intro h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.intro p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin: 0.5rem 0;
}

.emphasis {
    color: var(--text-secondary) !important;
    font-weight: 600;
    font-size: 1.2rem !important;
}

.categories {
    margin: 4rem 0;
}

.categories h2 {
    font-size: 1.8rem;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.category-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem;
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.3s ease;
    display: block;
}

.category-card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(74, 158, 255, 0.2);
}

.category-card h3 {
    color: var(--accent);
    margin-bottom: 0.5rem;
    font-size: 1.3rem;
}

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

.principles {
    margin: 4rem 0;
    padding: 2rem;
    background: var(--bg-secondary);
    border-radius: 8px;
    border: 1px solid var(--border);
}

.principles h2 {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.principles ul {
    list-style: none;
    padding-left: 0;
}

.principles li {
    margin: 1rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
}

.principles li::before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--text-secondary);
}

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

.tools {
    margin: 4rem 0;
    padding: 2rem;
    background: var(--bg-secondary);
    border-radius: 8px;
    border: 1px solid var(--border);
}

.tools h2 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.tools .section-intro {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 2rem;
    line-height: 1.8;
}

.tool-category {
    background: var(--bg-tertiary);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border);
    margin-bottom: 2rem;
}

.tool-category h3 {
    font-size: 1.3rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.tool-category ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.tool-category ul.engine-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.tool-category li {
    margin: 0.75rem 0;
    padding: 0;
    position: relative;
}

.engine-toggle {
    background: none;
    border: none;
    padding: 0.75rem 0;
    padding-left: 1.5rem;
    text-align: left;
    width: 100%;
    cursor: pointer;
    color: var(--text-secondary);
    line-height: 1.6;
    position: relative;
    transition: opacity 0.2s ease;
}

.engine-toggle strong {
    color: var(--accent);
}

.engine-toggle::before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--accent);
    transition: transform 0.2s ease;
}

.engine-toggle:hover {
    opacity: 0.8;
}

.engine-toggle:hover::before {
    transform: translateX(2px);
}

.engine-details {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    padding-left: 1.5rem;
    margin-top: 0.5rem;
}

.engine-details.expanded {
    max-height: 1000px;
}

.engine-details p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin: 0.75rem 0;
}

.engine-details p:first-child {
    margin-top: 0;
}

.engine-details a {
    color: var(--accent);
    text-decoration: none;
}

.engine-details a:hover {
    text-decoration: underline;
}

.tool-category strong {
    color: var(--text-primary);
}

.tools-note {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.8;
    font-style: italic;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
}

.blog {
    margin: 4rem 0;
    padding: 2rem;
}

.blog h2 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.blog p {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.8;
}

footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
    border-top: 1px solid var(--border);
    margin-top: 4rem;
}

/* Demo page styles */
.demo-container {
    max-width: 1600px;
    margin: 0 auto;
    padding: 2rem;
}

.demo-header {
    margin-bottom: 2rem;
}

.demo-header h1 {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.demo-header .breadcrumb {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.demo-header .breadcrumb a {
    color: var(--accent);
    text-decoration: none;
}

.demo-header .breadcrumb a:hover {
    text-decoration: underline;
}

.demo-header .demo-description {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-top: 1rem;
    max-width: 800px;
}

.demo-content {
    display: grid;
    grid-template-columns: 1fr 400px;
    gap: 2rem;
    margin-bottom: 3rem;
}

@media (max-width: 1200px) {
    .demo-content {
        grid-template-columns: 1fr;
    }
}

.visualization-panel {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1rem;
    min-height: 600px;
    position: relative;
}

.controls-panel {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem;
    height: fit-content;
    position: sticky;
    top: 2rem;
}

.control-group {
    margin-bottom: 1.5rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border);
}

.control-group:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.control-group h3 {
    font-size: 1rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.control-item {
    margin-bottom: 1rem;
}

.control-item label {
    display: block;
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 0.5rem;
}

.control-item input[type="range"] {
    width: 100%;
    margin-bottom: 0.5rem;
}

.control-item input[type="number"],
.control-item input[type="text"] {
    width: 100%;
    padding: 0.5rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: 4px;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.control-item input[type="checkbox"] {
    margin-right: 0.5rem;
}

.control-buttons {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.control-buttons button {
    flex: 1;
    min-width: 80px;
    padding: 0.75rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: 4px;
    color: var(--text-primary);
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s ease;
}

.control-buttons button:hover {
    background: var(--accent);
    border-color: var(--accent);
}

.control-buttons button:active {
    transform: scale(0.98);
}

.control-buttons button.active {
    background: var(--accent);
    border-color: var(--accent);
}

.info-section {
    margin: 3rem 0;
    padding: 2rem;
    background: var(--bg-secondary);
    border-radius: 8px;
    border: 1px solid var(--border);
}

.info-section h2 {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.info-section p,
.info-section ul {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.info-section ul {
    padding-left: 2rem;
}

.info-section code {
    background: var(--bg-tertiary);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
    color: var(--accent);
}

.info-section pre {
    background: var(--bg-tertiary);
    padding: 1rem;
    border-radius: 4px;
    overflow-x: auto;
    margin: 1rem 0;
}

.info-section pre code {
    background: none;
    padding: 0;
    color: var(--text-primary);
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
}

.about-content h1 {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
}

.about-content h2 {
    font-size: 1.8rem;
    color: var(--text-primary);
    margin-top: 3rem;
    margin-bottom: 1rem;
}

.about-content .lead {
    font-size: 1.2rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-radius: 8px;
    border-left: 4px solid var(--accent);
}

.about-content p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

.about-content ul, .about-content ol {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1.5rem;
    padding-left: 2rem;
}

.about-content li {
    margin: 0.75rem 0;
}

.about-content strong {
    color: var(--text-primary);
}

.about-content .back-link {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
}

.about-content .back-link a {
    color: var(--accent);
    text-decoration: none;
    font-size: 1.1rem;
}

.about-content .back-link a:hover {
    text-decoration: underline;
}