:root{
  --bg:#ffffff;--bg-alt:#f4f7fa;--surface:#ffffff;--text:#14212b;--muted:#56687a;--border:#dde5ec;
  --accent:#0891b2;--accent-soft:#e0f4f8;--hero-bg:#0b2233;--hero-muted:#a9c1d1;
  --code-bg:#0f2230;--code-text:#e6eef4;--inline-code:#eef4f8;
  --shadow:0 1px 2px rgba(15,35,50,.06),0 8px 24px rgba(15,35,50,.06);--radius:12px
}
@media (prefers-color-scheme:dark){:root{
  --bg:#0c151c;--bg-alt:#101c25;--surface:#132330;--text:#e6eef4;--muted:#98abba;--border:#223544;
  --accent:#38bdf8;--accent-soft:#12303f;--hero-bg:#071119;--code-bg:#08131b;--inline-code:#1a2d3b;
  --shadow:0 1px 2px rgba(0,0,0,.3),0 8px 24px rgba(0,0,0,.25)
}}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:80px}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.65;font-size:17px;-webkit-font-smoothing:antialiased}
a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}
.wrap{max-width:1120px;margin:0 auto;padding:0 20px}
.wrap.narrow{max-width:780px}

/* Header */
.top{position:sticky;top:0;z-index:50;background:var(--hero-bg);border-bottom:1px solid rgba(255,255,255,.06)}
.nav{display:flex;align-items:center;justify-content:space-between;height:64px;position:relative}
.logo img{height:42px;width:auto;display:block}
.nav ul{display:flex;gap:26px;list-style:none}
.nav ul a{color:var(--hero-muted);font-size:.92rem;font-weight:500}
.nav ul a:hover,.nav ul a[aria-current]{color:#fff;text-decoration:none}
.cta-sm{background:#0891b2;color:#fff;padding:8px 16px;border-radius:8px;font-weight:600;font-size:.9rem}
.cta-sm:hover{background:#0e7490;text-decoration:none}
.menu-btn{display:none;background:none;border:0;color:#fff;font-size:1.5rem;cursor:pointer;padding:6px}

/* Article hero */
.ahero{background:var(--hero-bg);color:#eaf3f8;padding:48px 0 44px}
.ahero.hub{padding:64px 0 56px}
.ahero h1{font-size:clamp(1.8rem,4vw,2.6rem);line-height:1.18;letter-spacing:-.01em;color:#fff;margin:14px 0 14px}
.ahero .dek{color:var(--hero-muted);font-size:1.1rem;max-width:720px}
.eyebrow{font-size:.8rem;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:#38bdf8}
.crumbs{font-size:.85rem;color:var(--hero-muted);margin-bottom:18px}
.crumbs a{color:var(--hero-muted)}.crumbs span{opacity:.5;margin:0 4px}
.byline{margin-top:18px;font-size:.88rem;color:var(--hero-muted)}
.kcat{display:inline-flex;gap:6px;align-items:center;font-size:.74rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--accent)}
.kcat.light{color:#38bdf8;background:rgba(56,189,248,.12);border:1px solid rgba(56,189,248,.3);padding:4px 10px;border-radius:999px}

/* TOC */
.toc{margin:32px 0 8px;border:1px solid var(--border);border-radius:var(--radius);padding:16px 20px;background:var(--bg-alt)}
.toc summary{cursor:pointer;font-weight:700;font-size:.95rem}
.toc ol{margin:10px 0 0 20px;font-size:.93rem}.toc li{margin:4px 0}

/* Prose */
.prose{padding:12px 0 8px}
.prose h2{font-size:1.5rem;line-height:1.25;margin:44px 0 12px;letter-spacing:-.01em}
.prose h3{font-size:1.15rem;margin:30px 0 8px}
.prose p{margin:0 0 18px}
.prose ul,.prose ol{margin:0 0 20px 24px}.prose li{margin:6px 0}
.prose strong{color:var(--text)}
.prose code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.86em;background:var(--inline-code);padding:2px 6px;border-radius:5px}
.prose pre{background:var(--code-bg);color:var(--code-text);border-radius:10px;padding:18px 20px;overflow-x:auto;margin:0 0 22px;font-size:.86rem;line-height:1.55}
.prose pre code{background:none;padding:0;font-size:inherit;color:inherit}
.prose table{width:100%;border-collapse:collapse;margin:0 0 24px;font-size:.93rem;display:block;overflow-x:auto}
.prose th,.prose td{border-bottom:1px solid var(--border);padding:10px 12px;text-align:left;vertical-align:top}
.prose th{background:var(--bg-alt);font-weight:700}
.prose blockquote{border-left:4px solid var(--accent);background:var(--accent-soft);padding:14px 18px;border-radius:0 10px 10px 0;margin:0 0 22px}
.prose blockquote p{margin:0}

/* CTA */
.cta{display:flex;gap:18px;align-items:flex-start;margin:40px 0 20px;padding:26px;border-radius:var(--radius);background:var(--hero-bg);color:#eaf3f8}
.cta h2{font-size:1.2rem;color:#fff;margin-bottom:6px}.cta p{color:var(--hero-muted);font-size:.95rem;margin-bottom:14px}
.cta-ic{flex:none;width:52px;height:52px;border-radius:12px;background:rgba(56,189,248,.14);color:#38bdf8;display:grid;place-items:center}
.btn{display:inline-block;background:#0891b2;color:#fff;padding:11px 20px;border-radius:9px;font-weight:600}
.btn:hover{background:#0e7490;text-decoration:none}

/* Cards */
.related{margin:40px 0 72px}.related h2{font-size:1.3rem;margin-bottom:16px}
.kgrid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.related .kgrid{grid-template-columns:1fr}
.kcard{display:block;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow);color:var(--text);transition:.15s}
.kcard:hover{text-decoration:none;transform:translateY(-2px);border-color:var(--accent)}
.kcard h3{font-size:1.06rem;line-height:1.3;margin:10px 0 8px}
.kcard p{color:var(--muted);font-size:.92rem}
.kmeta{display:block;margin-top:12px;font-size:.82rem;color:var(--muted)}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:32px 0 24px}
.chip{font:inherit;font-size:.86rem;border:1px solid var(--border);background:var(--surface);color:var(--text);padding:6px 14px;border-radius:999px;cursor:pointer}
.chip.on{background:var(--accent);border-color:var(--accent);color:#fff}
.hubgrid{margin-bottom:80px}

/* Footer */
footer{background:#060e14;color:#7f95a5;font-size:.86rem;padding:26px 0}
footer .wrap{display:flex;justify-content:space-between;align-items:flex-end;gap:12px;flex-wrap:wrap}
footer a{color:#a9c1d1}.flogo{height:34px;width:auto;display:block;margin-bottom:10px}

@media (max-width:900px){.kgrid{grid-template-columns:1fr 1fr}}
@media (max-width:720px){
  .menu-btn{display:block}
  .nav ul{display:none;position:absolute;top:64px;left:-20px;right:-20px;flex-direction:column;gap:0;background:var(--hero-bg);border-bottom:1px solid rgba(255,255,255,.08)}
  .nav ul.open{display:flex}.nav ul li a{display:block;padding:14px 20px}
  .cta-sm{display:none}.logo img{height:38px}
  .kgrid{grid-template-columns:1fr}
  .cta{flex-direction:column}
  .prose h2{font-size:1.3rem}
}