*{box-sizing:border-box;margin:0;padding:0}
body{font-family:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;background:#fff;color:#172033;line-height:1.65;-webkit-font-smoothing:antialiased}
.site-nav{background:#fff;border-bottom:1px solid #e5e7eb;height:56px;display:flex;align-items:center;padding:0 24px;position:sticky;top:0;z-index:100;gap:16px}
.nav-logo{font-size:18px;font-weight:800;text-decoration:none;color:#1a1a2e;white-space:nowrap}
.nav-logo span{color:#2563eb}.nav-logo svg{vertical-align:middle;margin-right:6px}.nav-spacer{flex:1}
.nav-links{display:flex;gap:20px;align-items:center}.nav-links a{font-size:14px;color:#6b7280;text-decoration:none;font-weight:500}.nav-links a:hover,.nav-links a[aria-current="page"]{color:#1d4ed8}
.nav-login{background:#eff6ff;color:#2563eb!important;border-radius:999px;padding:6px 14px;font-weight:600!important}
.theme-toggle{background:none;border:none;cursor:pointer;font-size:18px;padding:4px 6px;line-height:1;border-radius:6px;flex-shrink:0}
.article-header{background:#f8fafc;border-bottom:1px solid #e5e7eb;padding:54px 24px 48px}
.article-header-inner{max-width:820px;margin:0 auto}.eyebrow{color:#2563eb;font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.05em;margin-bottom:10px}
.article-header h1{font-size:40px;line-height:1.15;color:#111827;margin-bottom:16px;max-width:760px}.lead{font-size:18px;line-height:1.7;color:#4b5563;max-width:760px}.updated{font-size:12px;color:#9ca3af;margin-top:18px}
.article-layout{max-width:1050px;margin:0 auto;padding:50px 24px 80px;display:grid;grid-template-columns:220px minmax(0,720px);gap:56px}
.toc{position:sticky;top:82px;align-self:start}.toc-title{font-size:12px;font-weight:700;color:#111827;text-transform:uppercase;letter-spacing:.05em;margin-bottom:9px}.toc a{display:block;color:#64748b;text-decoration:none;font-size:13px;line-height:1.45;padding:6px 0;border-left:2px solid #e5e7eb;padding-left:12px}.toc a:hover{color:#2563eb;border-color:#3b82f6}
.article-body h2{font-size:26px;line-height:1.3;color:#111827;margin:46px 0 13px}.article-body h2:first-child{margin-top:0}.article-body h3{font-size:18px;line-height:1.4;color:#111827;margin:28px 0 8px}.article-body p{font-size:16px;color:#374151;margin-bottom:16px}.article-body ul,.article-body ol{margin:0 0 18px 22px;color:#374151}.article-body li{padding:3px 0}.article-body a{color:#2563eb}.note{margin:24px 0;padding:18px 20px;background:#eff6ff;border-left:3px solid #3b82f6;color:#1e3a5f;font-size:15px}.formula{margin:22px 0;border-top:1px solid #dbeafe;border-bottom:1px solid #dbeafe;padding:20px 0;color:#1d4ed8;font-size:17px;font-weight:700}.example{margin:22px 0;padding:22px;background:#f8fafc;border:1px solid #e5e7eb;border-radius:6px}.example strong{display:block;color:#111827;margin-bottom:6px}.article-cta{margin-top:50px;padding-top:28px;border-top:1px solid #e5e7eb}.article-cta h2{margin:0 0 8px;font-size:21px}.primary-link{display:inline-block;margin-top:12px;background:#2563eb;color:#fff!important;text-decoration:none;border-radius:6px;padding:10px 16px;font-size:14px;font-weight:700}
.site-footer{background:#1a1a2e;color:#fff;padding:40px 20px 0}.footer-inner{max-width:1100px;margin:0 auto;display:grid;grid-template-columns:2fr 1fr;gap:40px}.footer-inner h4{font-size:13px;font-weight:700;margin-bottom:12px;color:rgba(255,255,255,.5);text-transform:uppercase;letter-spacing:.05em}.footer-desc{font-size:13px;line-height:1.7;color:rgba(255,255,255,.65)}.footer-logo{font-size:18px;font-weight:800;margin-bottom:8px}.footer-logo span{color:#60a5fa}.footer-links a{display:block;font-size:13px;color:rgba(255,255,255,.55);text-decoration:none;padding:3px 0}.footer-links a:hover{color:#fff}.footer-bottom{border-top:1px solid rgba(255,255,255,.1);margin-top:32px;padding:16px 0;text-align:center;font-size:12px;color:rgba(255,255,255,.35)}
[data-theme="dark"] body{background:#0f1117;color:#e2e8f0}[data-theme="dark"] .site-nav{background:#13141c;border-color:#2d3148}[data-theme="dark"] .nav-logo,[data-theme="dark"] .toc-title,[data-theme="dark"] .article-header h1,[data-theme="dark"] .article-body h2,[data-theme="dark"] .article-body h3,[data-theme="dark"] .example strong{color:#e2e8f0}[data-theme="dark"] .nav-links a{color:#94a3b8}[data-theme="dark"] .article-header,[data-theme="dark"] .example{background:#171923;border-color:#2d3148}[data-theme="dark"] .article-header{border-color:#2d3148}[data-theme="dark"] .lead,[data-theme="dark"] .article-body p,[data-theme="dark"] .article-body ul,[data-theme="dark"] .article-body ol{color:#a7b0c0}[data-theme="dark"] .toc a{border-color:#2d3148;color:#94a3b8}[data-theme="dark"] .note{background:#172554;color:#bfdbfe}[data-theme="dark"] .article-cta,[data-theme="dark"] .formula{border-color:#2d3148}
@media(max-width:800px){.article-header{padding:42px 20px 38px}.article-header h1{font-size:32px}.lead{font-size:16px}.article-layout{display:block;padding:36px 20px 64px}.toc{position:static;border-bottom:1px solid #e5e7eb;padding-bottom:22px;margin-bottom:34px}.toc a{display:inline-block;border-left:0;padding:4px 14px 4px 0}.article-body h2{font-size:23px;margin-top:38px}.footer-inner{grid-template-columns:1fr}}