/* research-papers — GitHub Pages documentation site */
:root {
    --bg: #0d1117;
    --bg-elev: #161b22;
    --bg-card: #1c2128;
    --border: #30363d;
    --text: #e6edf3;
    --text-dim: #7d8590;
    --accent: #58a6ff;
    --accent-2: #f78166;
    --green: #3fb950;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", "Noto Sans SC", Roboto, Helvetica, Arial, sans-serif;
    --font-mono: "JetBrains Mono", "Fira Code", "SFMono-Regular", Menlo, Consolas, monospace;
}

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

html { scroll-behavior: smooth; }

body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-sans);
    line-height: 1.6;
    min-height: 100vh;
}

/* ============ NAVIGATION ============ */
.nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(13, 17, 23, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    padding: 12px 0;
}
.nav-inner {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.nav-brand {
    font-size: 1.1em;
    font-weight: 700;
    color: var(--text);
    text-decoration: none;
    letter-spacing: -0.01em;
}
.nav-brand .accent { color: var(--accent); }
.nav-links {
    display: flex;
    list-style: none;
    gap: 20px;
    align-items: center;
}
.nav-links a {
    color: var(--text-dim);
    text-decoration: none;
    font-size: 0.9em;
    transition: color 0.15s;
}
.nav-links a:hover { color: var(--accent); }
.nav-version {
    color: var(--green);
    font-size: 0.85em;
    font-family: var(--font-mono);
    background: rgba(63, 185, 80, 0.1);
    padding: 4px 10px;
    border-radius: 12px;
    border: 1px solid rgba(63, 185, 80, 0.3);
}

/* ============ HERO ============ */
.hero {
    background: radial-gradient(ellipse 80% 50% at 50% 0%, rgba(88, 166, 255, 0.12), transparent),
                radial-gradient(ellipse 60% 40% at 80% 20%, rgba(247, 129, 102, 0.08), transparent),
                var(--bg);
    padding: 80px 24px 60px;
    border-bottom: 1px solid var(--border);
}
.hero-inner {
    max-width: 1000px;
    margin: 0 auto;
    text-align: center;
}
.hero h1 {
    font-size: clamp(2em, 5vw, 3.5em);
    line-height: 1.1;
    margin-bottom: 20px;
    letter-spacing: -0.02em;
}
.hero .subtitle {
    font-size: 1.15em;
    color: var(--text-dim);
    max-width: 760px;
    margin: 0 auto 28px;
    line-height: 1.7;
}
.hero .subtitle code {
    background: rgba(88, 166, 255, 0.1);
    color: var(--accent);
    padding: 3px 8px;
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 0.85em;
}
.cta-row {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 28px;
}
.cta {
    display: inline-block;
    padding: 12px 24px;
    background: var(--accent);
    color: var(--bg);
    text-decoration: none;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.95em;
    transition: transform 0.1s, box-shadow 0.15s;
}
.cta:hover {
    transform: translateY(-1px);
    box-shadow: 0 8px 24px rgba(88, 166, 255, 0.3);
}
.cta.secondary {
    background: transparent;
    color: var(--text);
    border: 1px solid var(--border);
}
.cta.secondary:hover {
    border-color: var(--accent);
    box-shadow: 0 4px 16px rgba(88, 166, 255, 0.15);
}
.badges {
    display: flex;
    gap: 6px;
    justify-content: center;
    flex-wrap: wrap;
}
.badges img { height: 22px; }

/* ============ LAYOUT ============ */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 48px 24px;
}
.main-grid {
    display: grid;
    grid-template-columns: 240px 1fr;
    gap: 48px;
    align-items: start;
}
@media (max-width: 900px) {
    .main-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    .toc {
        position: static !important;
    }
}

/* ============ TOC ============ */
.toc {
    position: sticky;
    top: 80px;
    padding: 20px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 0.9em;
}
.toc h3 {
    font-size: 0.75em;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-dim);
    margin-bottom: 12px;
    margin-top: 16px;
}
.toc h3:first-child { margin-top: 0; }
.toc ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 6px;
}
.toc a {
    color: var(--text-dim);
    text-decoration: none;
    transition: color 0.15s;
    display: block;
    padding: 2px 0;
}
.toc a:hover { color: var(--accent); }

/* ============ CONTENT ============ */
.content section {
    margin-bottom: 56px;
    scroll-margin-top: 80px;
}
.content h1 {
    font-size: 2em;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
    display: flex;
    align-items: baseline;
    gap: 16px;
    flex-wrap: wrap;
}
.content h1 .subtitle {
    font-size: 0.5em;
    color: var(--text-dim);
    font-weight: 400;
    font-style: italic;
}
.content h2 {
    font-size: 1.5em;
    margin-bottom: 16px;
    margin-top: 32px;
    color: var(--text);
    border-bottom: 1px solid var(--border);
    padding-bottom: 8px;
}
.content h3 {
    font-size: 1.2em;
    margin-bottom: 12px;
    margin-top: 24px;
    color: var(--accent);
}
.content p {
    margin-bottom: 16px;
    color: var(--text);
}
.content code {
    font-family: var(--font-mono);
    background: var(--bg-card);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
    color: var(--accent);
    border: 1px solid var(--border);
}
.content pre {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 16px;
    overflow-x: auto;
    margin-bottom: 16px;
}
.content pre code {
    background: none;
    border: none;
    padding: 0;
    color: var(--text);
}

/* ============ FORMULA ============ */
.formula {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-left: 4px solid var(--accent);
    padding: 20px 24px;
    margin: 16px 0;
    font-family: var(--font-mono);
    font-size: 1.05em;
    text-align: center;
    border-radius: 6px;
    color: var(--text);
}
.formula strong { color: var(--accent); }

/* ============ TABLES ============ */
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 20px;
    font-size: 0.95em;
}
th, td {
    padding: 10px 14px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}
th {
    color: var(--accent);
    font-weight: 600;
    background: var(--bg-elev);
}
tr:hover td { background: rgba(88, 166, 255, 0.04); }
td code { font-size: 0.9em; }

/* ============ CARDS ============ */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 16px;
    margin: 16px 0;
}
.card {
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 20px;
    transition: border-color 0.15s, transform 0.1s;
}
.card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}
.card h4 {
    color: var(--accent);
    margin-bottom: 8px;
    font-size: 1.05em;
}
.card p {
    color: var(--text-dim);
    font-size: 0.9em;
    margin-bottom: 0;
}
.card .badge {
    display: inline-block;
    padding: 2px 8px;
    background: rgba(88, 166, 255, 0.15);
    color: var(--accent);
    border-radius: 10px;
    font-size: 0.75em;
    font-family: var(--font-mono);
    margin-bottom: 8px;
}

/* ============ ALERT ============ */
.alert {
    background: rgba(88, 166, 255, 0.06);
    border-left: 4px solid var(--accent);
    padding: 14px 20px;
    margin: 16px 0;
    border-radius: 4px;
    color: var(--text);
}
.alert.warn {
    background: rgba(247, 129, 102, 0.06);
    border-left-color: var(--accent-2);
}

/* ============ FOOTER ============ */
.footer {
    border-top: 1px solid var(--border);
    padding: 40px 24px;
    text-align: center;
    color: var(--text-dim);
    font-size: 0.9em;
}
.footer a {
    color: var(--accent);
    text-decoration: none;
}
.footer a:hover { text-decoration: underline; }

/* ============ DOC LIST ============ */
.doc-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.doc-list li {
    background: var(--bg-card);
    border: 1px solid var(--border);
    padding: 12px 16px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    gap: 12px;
    transition: border-color 0.15s;
}
.doc-list li:hover { border-color: var(--accent); }
.doc-list .doc-icon {
    font-family: var(--font-mono);
    background: var(--bg);
    border: 1px solid var(--border);
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.75em;
    color: var(--accent-2);
    min-width: 50px;
    text-align: center;
}
.doc-list .doc-name {
    flex: 1;
    color: var(--text);
}
.doc-list .doc-name a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 500;
}
.doc-list .doc-name a:hover { text-decoration: underline; }
.doc-list .doc-meta {
    color: var(--text-dim);
    font-size: 0.85em;
}