:root {
    --bg: #f7f8fa;
    --surface: #ffffff;
    --border: #e2e8f0;
    --border-strong: #cbd5e1;
    --text: #1e293b;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --primary: #1d4ed8;
    --primary-light: #dbeafe;
    --primary-dark: #1e3a8a;
    --accent: #f59e0b;
    --accent-light: #fef3c7;
    --success: #059669;
    --success-light: #d1fae5;
    --danger: #dc2626;
    --danger-light: #fee2e2;
    --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --max-w: 820px;
    --header-h: 56px;
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: var(--font); background: var(--bg); color: var(--text); font-size: 17px; line-height: 1.72; -webkit-font-smoothing: antialiased; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; height: auto; display: block; }

.site-header { background: var(--text); position: sticky; top: 0; z-index: 100; height: var(--header-h); }
.header-inner { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; display: flex; align-items: center; justify-content: space-between; height: 100%; }
.site-logo { color: #fff; font-size: 1.15rem; font-weight: 700; letter-spacing: -0.02em; }
.logo-accent { color: var(--accent); }
.header-inner nav { display: flex; gap: 1.5rem; }
.header-inner nav a { color: #cbd5e1; font-size: 0.875rem; font-weight: 500; text-decoration: none; }
.header-inner nav a:hover { color: #fff; }

.breadcrumb { max-width: var(--max-w); margin: 1rem auto 0; padding: 0 1.5rem; font-size: 0.8rem; color: var(--text-muted); }
.breadcrumb a { color: var(--text-muted); }
.breadcrumb .sep { margin: 0 0.4rem; }

.hero { max-width: var(--max-w); margin: 1.5rem auto 0; padding: 0 1.5rem; }
.hero h1 { font-size: 2.25rem; font-weight: 800; line-height: 1.2; letter-spacing: -0.03em; color: var(--text); margin-bottom: 0.75rem; }
.hero .kicker { display: inline-block; font-size: 0.75rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; color: var(--primary); background: var(--primary-light); padding: 0.25rem 0.6rem; margin-bottom: 0.75rem; }
.hero-sub { font-size: 1.1rem; color: var(--text-secondary); line-height: 1.65; max-width: 680px; }
.hero-badges { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 1rem; }

.badge { display: inline-flex; align-items: center; gap: 0.3rem; font-size: 0.75rem; font-weight: 600; padding: 0.3rem 0.65rem; border: 1px solid var(--border); color: var(--text-secondary); background: var(--surface); }
.badge-blue { border-color: var(--primary); color: var(--primary); background: var(--primary-light); }
.badge-green { border-color: var(--success); color: var(--success); background: var(--success-light); }
.badge-amber { border-color: var(--accent); color: #92400e; background: var(--accent-light); }

.author-block { max-width: var(--max-w); margin: 1.5rem auto 0; padding: 0 1.5rem; display: flex; align-items: flex-start; gap: 1rem; border-top: 2px solid var(--text); padding-top: 1rem; }
.author-avatar { width: 48px; height: 48px; background: var(--primary); color: #fff; display: flex; align-items: center; justify-content: center; font-weight: 700; font-size: 0.9rem; flex-shrink: 0; }
.author-name { font-weight: 700; font-size: 0.95rem; }
.author-name a { color: var(--text); }
.author-role { font-size: 0.8rem; color: var(--text-secondary); margin-top: 0.1rem; }
.author-meta { font-size: 0.75rem; color: var(--text-muted); margin-top: 0.25rem; display: flex; flex-wrap: wrap; gap: 0.3rem 1rem; }
.author-meta .verified { color: var(--success); font-weight: 600; }
.reviewer-line { max-width: var(--max-w); margin: 0.5rem auto 0; padding: 0 1.5rem; font-size: 0.8rem; color: var(--text-muted); padding-left: calc(1.5rem + 60px); }
.reviewer-line strong a { color: var(--text-secondary); }

.content-wrap { max-width: var(--max-w); margin: 2rem auto 3rem; padding: 0 1.5rem; }
.content-wrap h2 { font-size: 1.55rem; font-weight: 800; letter-spacing: -0.02em; margin: 2.5rem 0 0.75rem; padding-top: 1.5rem; border-top: 1px solid var(--border); color: var(--text); }
.content-wrap h2:first-of-type { border-top: none; padding-top: 0; margin-top: 1.5rem; }
.content-wrap h3 { font-size: 1.2rem; font-weight: 700; margin: 1.75rem 0 0.6rem; color: var(--text); }
.content-wrap h4 { font-size: 1rem; font-weight: 700; margin: 1.25rem 0 0.4rem; color: var(--primary-dark); }
.content-wrap p { margin-bottom: 1rem; }
.content-wrap sup a { color: var(--primary); font-weight: 600; text-decoration: none; font-size: 0.75em; }

.toc { background: var(--surface); border: 1px solid var(--border); padding: 1.25rem 1.5rem; margin-bottom: 2rem; }
.toc-label { font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.1em; color: var(--primary); margin-bottom: 0.6rem; }
.toc ol { padding-left: 1.2rem; }
.toc li { font-size: 0.9rem; margin: 0.3rem 0; }
.toc li a { color: var(--text-secondary); }
.toc li a:hover { color: var(--primary); }

.info-card { background: var(--surface); border: 1px solid var(--border); border-left: 4px solid var(--primary); padding: 1rem 1.25rem; margin: 1.5rem 0; }
.info-card.success { border-left-color: var(--success); }
.info-card.warning { border-left-color: var(--danger); }
.info-card.amber { border-left-color: var(--accent); }
.info-card-title { font-size: 0.8rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 0.4rem; color: var(--text); }

.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 1rem; margin: 1.5rem 0; }
.stat-box { background: var(--surface); border: 1px solid var(--border); padding: 1rem; text-align: center; }
.stat-val { font-size: 1.75rem; font-weight: 800; color: var(--primary); letter-spacing: -0.02em; }
.stat-label { font-size: 0.78rem; color: var(--text-secondary); margin-top: 0.2rem; }

.comparison-table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; font-size: 0.88rem; background: var(--surface); }
.comparison-table th { background: var(--text); color: #fff; font-weight: 600; padding: 0.65rem 0.75rem; text-align: left; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.04em; }
.comparison-table td { padding: 0.6rem 0.75rem; border-bottom: 1px solid var(--border); }
.comparison-table tr:hover td { background: var(--primary-light); }

.faq-item { border-bottom: 1px solid var(--border); padding: 1rem 0; }
.faq-q { font-weight: 700; font-size: 1rem; color: var(--text); margin-bottom: 0.4rem; }
.faq-q::before { content: "F"; display: inline-block; width: 22px; height: 22px; background: var(--primary); color: #fff; font-size: 0.7rem; font-weight: 700; text-align: center; line-height: 22px; margin-right: 0.5rem; }
.faq-a { color: var(--text-secondary); font-size: 0.95rem; margin: 0; padding-left: calc(22px + 0.5rem); }

.editorial-section { border-top: 2px solid var(--text); margin-top: 2.5rem; padding-top: 1.5rem; }
.editorial-section h3 { font-size: 1rem; margin: 1.25rem 0 0.6rem; }
.sources-list { padding-left: 0; list-style: none; }
.sources-list li { font-size: 0.82rem; color: var(--text-secondary); margin: 0.35rem 0; padding-left: 2rem; position: relative; }
.src-num { position: absolute; left: 0; font-weight: 700; color: var(--primary); font-size: 0.78rem; }

.method-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 1rem; margin: 1rem 0 1.5rem; }
.method-card { background: var(--surface); border: 1px solid var(--border); padding: 1rem; }
.method-num { font-size: 2rem; font-weight: 800; color: var(--primary-light); line-height: 1; }
.method-title { font-weight: 700; font-size: 0.9rem; margin: 0.3rem 0 0.25rem; }
.method-desc { font-size: 0.8rem; color: var(--text-secondary); margin: 0; }

.transparency-box { background: var(--accent-light); border: 1px solid #fbbf24; padding: 1rem 1.25rem; font-size: 0.85rem; color: #78350f; margin: 1.5rem 0; }
.transparency-box strong { color: #92400e; }

.team-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 1rem; margin: 1rem 0 1.5rem; }
.team-card { background: var(--surface); border: 1px solid var(--border); padding: 1.25rem; }
.team-avatar { width: 56px; height: 56px; background: var(--primary); color: #fff; display: flex; align-items: center; justify-content: center; font-weight: 700; font-size: 1rem; margin-bottom: 0.75rem; }
.team-name { font-weight: 700; font-size: 1rem; }
.team-role { font-size: 0.82rem; color: var(--primary); font-weight: 600; }
.team-bio { font-size: 0.85rem; color: var(--text-secondary); margin-top: 0.5rem; }
.team-quals { font-size: 0.78rem; color: var(--text-muted); margin-top: 0.4rem; }

.site-footer { background: var(--text); color: #94a3b8; padding: 2.5rem 0 1.5rem; margin-top: 3rem; }
.footer-inner { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 2rem; }
.footer-brand { font-size: 0.88rem; line-height: 1.6; }
.footer-brand strong { color: #fff; display: block; margin-bottom: 0.3rem; }
.footer-col h4 { color: #e2e8f0; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 0.6rem; }
.footer-col a { display: block; color: #94a3b8; font-size: 0.85rem; margin: 0.3rem 0; text-decoration: none; }
.footer-col a:hover { color: #fff; }
.footer-bottom { max-width: 1100px; margin: 1.5rem auto 0; padding: 1rem 1.5rem 0; border-top: 1px solid #334155; font-size: 0.78rem; color: #64748b; }
.footer-disclaimer { margin-top: 0.5rem; line-height: 1.5; }

@media (max-width: 768px) {
    .hero h1 { font-size: 1.6rem; }
    .footer-inner { grid-template-columns: 1fr; }
    .author-block { flex-direction: column; gap: 0.5rem; }
    .reviewer-line { padding-left: 1.5rem; }
    .stat-row { grid-template-columns: 1fr; }
    .header-inner nav { gap: 0.8rem; }
    .header-inner nav a { font-size: 0.78rem; }
}