/* Landing Page Styles - Dark Theme, Compact, Accessible */

:root {
    /* Dark theme colors with WCAG AAA contrast */
    --primary-color: #60a5fa;
    --primary-dark: #3b82f6;
    --primary-light: #93c5fd;
    --accent-color: #34d399;

    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;

    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;

    --border-color: #334155;
    --border-light: #475569;

    --warning-color: #fbbf24;

    --radius-sm: 4px;
    --radius-md: 6px;
    --radius-lg: 8px;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
}

.container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Navigation - Compact */
.navbar {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 1.5rem;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1.5rem;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

.nav-brand h1 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.nav-subtitle {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 0.1rem;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 1.5rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s ease;
    font-size: 0.9rem;
}

.nav-link:hover,
.nav-link:focus {
    color: var(--primary-color);
    outline: none;
}

/* Main Content - Compact */
.main {
    flex: 1;
    padding: 2rem 1.5rem;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

/* Sections - Reduced spacing */
.section {
    margin-bottom: 2.5rem;
}

.section-header {
    margin-bottom: 1.25rem;
}

.section-header h2 {
    font-size: 1.4rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
    color: var(--text-primary);
}

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

/* Collapsible sections */
.collapsible {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
}

.collapsible-header {
    cursor: pointer;
    padding: 1rem 1.25rem;
    user-select: none;
    transition: all 0.2s ease;
    list-style: none;
}

.collapsible-header::-webkit-details-marker {
    display: none;
}

.collapsible-header::before {
    content: '▶';
    display: inline-block;
    margin-right: 0.75rem;
    transition: transform 0.2s ease;
    color: var(--primary-color);
    font-size: 0.8rem;
}

details[open] .collapsible-header::before {
    transform: rotate(90deg);
}

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

.collapsible-header h2 {
    display: inline;
    margin: 0;
}

.collapsible-content {
    padding: 0 1.25rem 1.25rem;
}

.section:has(.collapsible) {
    margin-bottom: 1.5rem;
}

/* Grids - Compact */
.projects-grid,
.utilities-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.25rem;
}

/* Cards - Compact dark theme */
.project-card,
.utility-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
}

.project-card:not(.coming-soon):hover,
.utility-card:not(.coming-soon):hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.project-card.coming-soon,
.utility-card.coming-soon {
    opacity: 0.6;
    cursor: default;
}

.project-card h3,
.utility-card h3 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.project-card p,
.utility-card p {
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    flex-grow: 1;
    font-size: 0.9rem;
    line-height: 1.5;
}

.utility-features {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin: 0.75rem 0;
}

.feature {
    background: var(--bg-tertiary);
    padding: 0.3rem 0.7rem;
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

/* Badges */
.badge {
    display: inline-block;
    background: var(--warning-color);
    color: var(--bg-primary);
    padding: 0.3rem 0.8rem;
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    font-weight: 600;
    text-align: center;
    margin-top: 0.75rem;
}

/* Buttons - High contrast */
.btn {
    display: inline-block;
    padding: 0.65rem 1.25rem;
    border-radius: var(--radius-md);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.2s ease;
    border: none;
    cursor: pointer;
    font-size: 0.9rem;
    text-align: center;
}

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

.btn-primary:hover,
.btn-primary:focus {
    background: var(--primary-light);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.btn-block {
    width: 100%;
    margin-top: auto;
}

/* Teaching Section */
.teaching-section {
    background: var(--bg-secondary);
    padding: 2rem 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

/* About Section - Compact */
.about-content {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.about-content p {
    margin-bottom: 1.25rem;
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

.about-content p:last-child {
    margin-bottom: 0;
}

/* Tech Stack - Compact */
.tech-stack {
    margin: 1.5rem 0;
    padding: 1.5rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-light);
}

.tech-stack h3 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.tech-category {
    margin-bottom: 1.25rem;
}

.tech-category:last-child {
    margin-bottom: 0;
}

.tech-category h4 {
    font-size: 0.9rem;
    color: var(--primary-light);
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.tech-items {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tech-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 0.4rem 0.8rem;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    color: var(--text-primary);
    transition: all 0.2s ease;
}

.tech-item:hover {
    border-color: var(--primary-color);
    background: var(--bg-primary);
}

/* Footer - Compact */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 1.5rem;
    text-align: center;
    margin-top: auto;
}

.footer p {
    margin: 0.35rem 0;
    font-size: 0.85rem;
}

.footer a {
    color: var(--primary-light);
    text-decoration: none;
    font-weight: 600;
}

.footer a:hover,
.footer a:focus {
    color: var(--primary-color);
    text-decoration: underline;
}

/* Responsive - Compact */
@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
        padding: 1rem;
    }

    .nav-links {
        gap: 1rem;
        font-size: 0.85rem;
    }

    .projects-grid,
    .utilities-grid {
        grid-template-columns: 1fr;
    }

    .section-header h2 {
        font-size: 1.3rem;
    }

    .main {
        padding: 1.5rem 1rem;
    }

    .section {
        margin-bottom: 2rem;
    }

    .teaching-section {
        padding: 1.5rem 1rem;
    }
}

@media (max-width: 480px) {
    .nav-brand h1 {
        font-size: 1.1rem;
    }

    .nav-subtitle {
        font-size: 0.75rem;
    }

    .btn {
        padding: 0.55rem 1rem;
        font-size: 0.85rem;
    }
}