:root {
    --bg-dark: #0f172a;
    --bg-card: #1e293b;
    --bg-alt: #131c31;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --accent: #38bdf8;
    --accent-hover: #0284c7;
    --border: #334155;
}

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

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

.container {
    max-width: 1180px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.site-header {
    border-bottom: 1px solid var(--border);
    background: rgba(15, 23, 42, 0.9);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 68px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    font-weight: 700;
    font-size: 1.15rem;
}

.brand-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #22c55e;
    box-shadow: 0 0 10px #22c55e;
}

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

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color 0.2s;
}

.nav-links a:hover {
    color: var(--text-main);
}

.hero {
    padding: 4.5rem 0 3.5rem;
    text-align: center;
    border-bottom: 1px solid var(--border);
}

.badge {
    display: inline-block;
    padding: 0.35rem 0.9rem;
    border-radius: 999px;
    background: rgba(56, 189, 248, 0.12);
    color: var(--accent);
    border: 1px solid rgba(56, 189, 248, 0.3);
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 1.2rem;
}

.hero h1 {
    font-size: clamp(2rem, 4vw, 3rem);
    letter-spacing: -0.02em;
    margin-bottom: 1rem;
}

.hero-subtitle {
    max-width: 680px;
    margin: 0 auto 2rem;
    color: var(--text-muted);
    font-size: 1.1rem;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 0.7rem 1.4rem;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    font-size: 0.95rem;
    transition: all 0.2s;
}

.btn-primary {
    background: var(--accent);
    color: #0f172a;
}

.btn-primary:hover {
    background: #7dd3fc;
}

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

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

.section {
    padding: 4rem 0;
}

.section-alt {
    background: var(--bg-alt);
    border-top: 1px solid var(--border);
}

.section-header {
    margin-bottom: 2.5rem;
}

.section-header h2 {
    font-size: 1.75rem;
    margin-bottom: 0.4rem;
}

.section-header p {
    color: var(--text-muted);
}

.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(460px, 1fr));
    gap: 2rem;
}

@media (max-width: 600px) {
    .project-grid {
        grid-template-columns: 1fr;
    }
}

.project-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.card-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.tag {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--accent);
    font-weight: 700;
}

.dataset-badge {
    font-family: monospace;
    font-size: 0.82rem;
    background: #0f172a;
    padding: 0.2rem 0.6rem;
    border-radius: 6px;
    border: 1px solid var(--border);
}

.project-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.iframe-preview {
    width: 100%;
    height: 420px;
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--border);
    background: #ffffff;
}

.iframe-preview iframe {
    width: 100%;
    height: 100%;
    border: none;
}

.card-actions {
    margin-top: auto;
    padding-top: 0.5rem;
}

.stack-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.stack-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 1.5rem;
}

.stack-item h4 {
    margin-bottom: 0.5rem;
    color: var(--accent);
}

.stack-item p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.site-footer {
    border-top: 1px solid var(--border);
    padding: 2rem 0;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

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