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

:root {
    --primary-color: #000000;
    --primary-light: #404040;
    --background: #ffffff;
    --surface: #f8fafc;
    --surface-hover: #e2e8f0;
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --border-color: #cbd5e1;
    --success-color: #059669;
    --border-radius: 8px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.8;
    font-size: 18px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Site-level header with logo and navigation */
.site-header {
    background: #ffffff;
    border-bottom: 2px solid var(--border-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.site-header-content {
    max-width: 1100px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    color: var(--primary-color);
    font-size: 1.4rem;
    font-weight: 700;
}

.logo img {
    height: 60px;
    width: auto;
}

.main-nav {
    display: flex;
    gap: 0.5rem;
}

.main-nav a {
    padding: 0.75rem 1.25rem;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.05rem;
    border-radius: 6px;
    transition: background 0.2s;
}

.main-nav a:hover {
    background: var(--surface);
}

.main-nav a.active {
    background: var(--primary-color);
    color: white;
}

/* Page-specific header */
.page-header {
    background: var(--surface);
    text-align: center;
    padding: 2.5rem 2rem;
    border-bottom: 1px solid var(--border-color);
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: var(--primary-color);
    letter-spacing: -0.5px;
}

.page-description {
    font-size: 1.2rem;
    color: var(--text-secondary);
    font-weight: 400;
    line-height: 1.6;
    max-width: 800px;
    margin: 0 auto;
}

main {
    flex: 1;
    max-width: 1100px;
    width: 100%;
    margin: 0 auto;
    padding: 4rem 2.5rem;
    background: var(--background);
}

.demo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 3rem;
    margin-bottom: 2rem;
}

.demo-card {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 2.5rem;
    padding-bottom: 5rem;
    border: 2px solid var(--border-color);
    display: block;
    position: relative;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08);
}

.demo-card-link {
    text-decoration: none;
    color: inherit;
    display: block;
}

.demo-card:hover {
    border-color: var(--primary-light);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.12);
}

.demo-card.placeholder {
    opacity: 0.6;
    border: 2px dashed var(--border-color);
    cursor: default;
}

.demo-card.placeholder:hover {
    border-color: var(--border-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08);
}

.demo-card-content h2 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-weight: 600;
    line-height: 1.3;
}

.demo-card-content p {
    color: var(--text-secondary);
    margin-bottom: 1.25rem;
    line-height: 1.7;
    font-size: 1.05rem;
}

.demo-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1.25rem;
}

.tag {
    display: inline-block;
    padding: 0.4rem 1rem;
    background: #dbeafe;
    color: var(--primary-color);
    border-radius: 4px;
    font-size: 0.95rem;
    font-weight: 600;
    border: 1px solid #93c5fd;
}

.demo-actions {
    position: absolute;
    bottom: 1.5rem;
    right: 1.5rem;
    display: flex;
    gap: 0.75rem;
    z-index: 10;
}

.run-btn,
.download-btn {
    color: white;
    border: none;
    padding: 0.75rem 1.25rem;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
}

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

.run-btn:hover {
    background: var(--primary-light);
}

.download-btn {
    background: var(--success-color);
}

.download-btn:hover {
    background: #047857;
}

.run-btn:active,
.download-btn:active {
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.15);
}

.run-btn svg,
.download-btn svg {
    width: 18px;
    height: 18px;
}

/* Content pages styling */
.content-section {
    max-width: 900px;
    margin: 0 auto 1.5rem;
    padding: 1.5rem;
    background: var(--surface);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
}

.content-section h2 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 0.75rem;
    font-weight: 700;
}

.content-section h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-top: 2rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.content-section p {
    margin-bottom: 1.25rem;
    line-height: 1.8;
}

.content-section ul,
.content-section ol {
    margin-bottom: 1.5rem;
}

.learning-list,
.getting-started-list {
    list-style-position: outside;
    margin-left: 1.5rem;
    line-height: 1.8;
}

.learning-list li,
.getting-started-list li {
    margin-bottom: 1rem;
    padding-left: 0.5rem;
}

/* Feature cards on home page */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    padding-bottom: 1.5rem;
    border-radius: var(--border-radius);
    border: 2px solid var(--border-color);
    text-decoration: none;
    color: inherit;
    display: flex;
    flex-direction: column;
    transition: all 0.3s ease;
    cursor: pointer;
}

.feature-card:hover {
    border-color: var(--primary-color);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    transform: translateY(-4px);
}

.feature-card-content {
    flex: 1;
}

.feature-card h3 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-weight: 600;
}

.feature-card p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.feature-button {
    display: block;
    background: var(--primary-color);
    color: white;
    text-align: center;
    padding: 0.875rem 1.5rem;
    border-radius: 6px;
    font-weight: 600;
    font-size: 1.05rem;
    margin-top: 1rem;
    transition: background 0.2s ease;
}

.feature-card:hover .feature-button {
    background: var(--primary-light);
}

/* Links page styling */
.links-list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.75rem;
    margin-top: 1rem;
}

@media (min-width: 900px) {
    .links-list {
        grid-template-columns: 1fr 1fr;
    }
}

.link-item {
    background: white;
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
}

.link-item h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0 0 0.25rem 0;
}

.link-url {
    display: inline-block;
    color: var(--primary-color);
    text-decoration: underline;
    font-size: 0.85rem;
    font-weight: 500;
    margin-bottom: 0.25rem;
    word-break: break-all;
}

.link-url:hover {
    color: var(--primary-light);
}

.link-description {
    color: var(--text-secondary);
    line-height: 1.4;
    margin: 0;
    font-size: 0.85rem;
}

@media (max-width: 768px) {
    body {
        font-size: 17px;
    }

    .site-header-content {
        flex-direction: column;
        padding: 1rem 1.5rem;
        gap: 1rem;
    }

    .main-nav {
        width: 100%;
        flex-direction: column;
        gap: 0.5rem;
    }

    .main-nav a {
        width: 100%;
        text-align: center;
        padding: 0.85rem 1rem;
        font-size: 1.1rem;
    }

    .page-header h1 {
        font-size: 2.25rem;
    }

    .page-description {
        font-size: 1.1rem;
    }

    .demo-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    main {
        padding: 3rem 1.5rem;
    }

    .demo-card {
        padding: 2rem;
        padding-bottom: 4.5rem;
    }

    .content-section {
        padding: 1.25rem;
    }

    .feature-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
}

@media (max-width: 480px) {
    body {
        font-size: 16px;
    }

    .site-header-content {
        padding: 1rem;
    }

    .logo {
        font-size: 1.25rem;
    }

    .logo img {
        height: 48px;
    }

    .main-nav a {
        padding: 0.75rem 1rem;
        font-size: 1.05rem;
    }

    .page-header {
        padding: 2rem 1.5rem;
    }

    .page-header h1 {
        font-size: 2rem;
    }

    .page-description {
        font-size: 1.05rem;
    }

    .demo-card-content h2 {
        font-size: 1.5rem;
    }

    .demo-actions {
        flex-direction: column;
        right: 1rem;
        bottom: 1rem;
        gap: 0.5rem;
    }

    .run-btn,
    .download-btn {
        padding: 0.65rem 1rem;
        font-size: 0.95rem;
        width: 100%;
        justify-content: center;
    }

    .content-section {
        padding: 1rem;
    }

    .content-section h2 {
        font-size: 1.35rem;
    }

    .content-section h3 {
        font-size: 1.2rem;
    }

    .feature-card {
        padding: 1.5rem;
        padding-bottom: 1.25rem;
    }

    .feature-button {
        font-size: 1rem;
        padding: 0.75rem 1.25rem;
    }

    .link-item {
        padding: 0.75rem;
    }

    .link-item h3 {
        font-size: 0.95rem;
    }

    .link-url {
        font-size: 0.8rem;
    }

    .link-description {
        font-size: 0.8rem;
    }
}