:root{
  --bg:#fbfaf7;--surface:#ffffff;--surface-2:#f3f1ea;--ink:#16181f;--ink-2:#444a5c;--muted:#6b7183;
  --line:#e3e0d6;--accent:#b45309;--accent-ink:#ffffff;--brand:#f59e0b;--brand-2:#ea580c;
  --link:#9a3f07;--quick:#fff7e6;--quick-line:#f5c56b;--ok:#166534;--warn:#9a3412;
  --b1:#d97706;--b2:#475569;--code:#f1efe8;
  --radius:10px;--maxw:760px;--wide:1120px;
  --font:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
@media (prefers-color-scheme:dark){:root{
  --bg:#0c0e18;--surface:#141726;--surface-2:#1b1f33;--ink:#eceef7;--ink-2:#c3c7da;--muted:#9096b2;
  --line:#2a2f48;--accent:#f59e0b;--accent-ink:#1a1206;--link:#fbbf24;--quick:#1f1a0e;--quick-line:#7c5a12;
  --ok:#4ade80;--warn:#fdba74;--b1:#f59e0b;--b2:#94a3b8;--code:#1b1f33;
}}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.65 var(--font)}
a{color:var(--link);text-underline-offset:2px}
a:hover{text-decoration-thickness:2px}
img,svg{max-width:100%;height:auto}
.wrap{max-width:var(--wide);margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-9999px}.skip:focus{left:12px;top:12px;background:var(--surface);padding:8px 12px;z-index:9}
.muted{color:var(--muted)}
/* header */
.site-header{background:#0c0e18;border-bottom:1px solid #22263a}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:62px;flex-wrap:wrap}
.logo{font-weight:800;font-size:1.2rem;letter-spacing:-.02em;color:#f2f3fa;text-decoration:none}
.logo span{background:linear-gradient(90deg,#f7b733,#fc4a1a);-webkit-background-clip:text;background-clip:text;color:transparent}
.nav{display:flex;gap:4px 18px;flex-wrap:wrap}
.nav a{color:#c9cde0;text-decoration:none;font-size:.95rem;padding:6px 0}
.nav a:hover{color:#fff}
.nav-rg{color:#fbbf24!important}
.crumbs ol{list-style:none;display:flex;flex-wrap:wrap;gap:4px;padding:14px 0 0;margin:0;font-size:.85rem;color:var(--muted)}
.crumbs li+li::before{content:"/";margin:0 6px;color:var(--line)}
.crumbs a{color:var(--muted)}
/* article */
.article{max-width:calc(var(--maxw) + 40px);padding-top:8px;padding-bottom:40px}
.art-head{padding:18px 0 6px}
.kicker{margin:0 0 6px;font-size:.82rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--accent)}
.kicker a{color:inherit;text-decoration:none}
h1{font-size:clamp(1.8rem,4.2vw,2.5rem);line-height:1.15;letter-spacing:-.02em;margin:0 0 12px}
.lede{font-size:1.15rem;color:var(--ink-2);margin:0 0 12px}
.byline{font-size:.9rem;color:var(--muted);margin:0 0 6px}
.disclosure-line{font-size:.82rem;color:var(--muted);margin:0 0 6px;border-left:3px solid var(--line);padding-left:10px}
.quick{background:var(--quick);border:1px solid var(--quick-line);border-radius:var(--radius);padding:14px 18px;margin:18px 0}
.quick p{margin:0}.quick-label{font-weight:800;font-size:.8rem;text-transform:uppercase;letter-spacing:.06em;color:var(--accent);margin-bottom:4px!important}
.table-wrap{overflow-x:auto;margin:18px 0;-webkit-overflow-scrolling:touch}
table{border-collapse:collapse;width:100%;font-size:.93rem;background:var(--surface)}
caption{text-align:left;font-weight:700;padding:0 0 8px;color:var(--ink)}
th,td{border:1px solid var(--line);padding:8px 10px;text-align:left;vertical-align:top}
thead th{background:var(--surface-2);font-weight:700}
tbody th{font-weight:600}
table.facts th{width:42%;background:var(--surface-2)}
table.data td{font-variant-numeric:tabular-nums}
.toc{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:12px 18px;margin:18px 0}
.toc-h{font-weight:700;margin:0 0 4px}.toc ol{margin:0;padding-left:20px;columns:2;column-gap:28px;font-size:.93rem}
@media (max-width:640px){.toc ol{columns:1}}
.prose h2{font-size:1.5rem;line-height:1.25;margin:2.2em 0 .5em;letter-spacing:-.01em}
.prose h3{font-size:1.18rem;margin:1.6em 0 .4em}
.prose p,.prose li{color:var(--ink)}
.prose code,.formula code{font-family:var(--mono);background:var(--code);padding:1px 5px;border-radius:5px;font-size:.88em}
.prose blockquote{border-left:3px solid var(--brand);margin:1em 0;padding:2px 16px;color:var(--ink-2)}
.formula{background:var(--surface);border:1px dashed var(--line);border-radius:var(--radius);padding:12px 16px;margin:16px 0}
.formula code{font-size:1em;background:none;padding:0}.formula p{margin:6px 0 0;font-size:.93rem;color:var(--ink-2)}
.chart{margin:22px 0;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:14px 14px 6px}
.chart figcaption{font-size:.95rem;margin-bottom:6px}
.chart svg{display:block;width:100%}
.chart .b1{fill:var(--b1)}.chart .b2{fill:var(--b2)}.chart .axis{stroke:var(--line)}
.chart .tick{fill:var(--muted);font-size:11px;font-family:var(--font)}
.chart .lbl{fill:var(--ink);font-size:13px;font-family:var(--font)}
.chart .val{fill:var(--ink-2);font-size:12px;font-family:var(--font)}
.legend{font-size:.85rem;color:var(--muted);margin:0 0 4px}.sw{display:inline-block;width:10px;height:10px;border-radius:2px;margin:0 4px 0 8px}
.sw.s1{background:var(--b1)}.sw.s2{background:var(--b2)}
.method,.callout,.toolcard,.rg-note,.changelog{border-radius:var(--radius);padding:12px 16px;margin:20px 0;font-size:.93rem}
.method{background:var(--surface-2);border:1px solid var(--line)}
.method p,.callout p,.toolcard p,.rg-note p,.changelog p{margin:.3em 0}
.method-h,.callout-h{font-weight:700;margin:0 0 2px!important}
.callout{background:var(--surface);border-left:4px solid var(--brand)}
.callout.warn{border-left-color:var(--brand-2)}
.toolcard{background:var(--quick);border:1px solid var(--quick-line)}
.dl{font-weight:600}
.dl::before{content:"↓ "}
.faq details{border-bottom:1px solid var(--line);padding:4px 0}
.faq summary{cursor:pointer;list-style:none;padding:8px 0}
.faq summary::-webkit-details-marker{display:none}
.faq summary h3{display:inline;font-size:1.05rem;margin:0}
.faq summary::before{content:"+";display:inline-block;width:1.2em;color:var(--accent);font-weight:700}
.faq details[open] summary::before{content:"−"}
.faq details p{margin:0 0 12px 1.2em}
.cta{background:linear-gradient(135deg,#141726,#1f1a2e);color:#eceef7;border-radius:14px;padding:20px 22px;margin:28px 0}
.cta-h{font-size:1.2rem;font-weight:800;margin:0 0 6px}.cta p{margin:0 0 12px;color:#c9cde0}
.cta .cta-small{font-size:.8rem;color:#9096b2;margin:12px 0 0}.cta .cta-small a{color:#fbbf24}
.btn{display:inline-block;background:linear-gradient(90deg,#f7b733,#f97316);color:#1a1206;font-weight:800;text-decoration:none;border-radius:999px;padding:10px 20px}
.btn.ghost{background:transparent;color:inherit;border:1px solid currentColor}
.rg-note{background:var(--surface);border:1px solid var(--line)}
.sources ol{font-size:.88rem;padding-left:22px}.sources li{margin:.35em 0}
.sources h2,.related h2{font-size:1.2rem;margin:1.8em 0 .5em}
.cards{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:12px}
.cards a{display:block;height:100%;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:12px 14px;text-decoration:none;color:var(--ink);font-weight:650;line-height:1.35}
.cards a:hover{border-color:var(--brand)}
.card-k{display:block;font-size:.72rem;font-weight:800;text-transform:uppercase;letter-spacing:.07em;color:var(--accent);margin-bottom:4px}
.card-d{display:block;font-weight:400;font-size:.86rem;color:var(--muted);margin-top:6px}
.chips{list-style:none;padding:0;display:flex;flex-wrap:wrap;gap:8px}
.chips a{display:inline-block;border:1px solid var(--line);border-radius:999px;padding:4px 12px;text-decoration:none;color:var(--ink-2);font-size:.9rem;background:var(--surface)}
.changelog{border-top:1px solid var(--line);border-radius:0;padding-left:0}
.hub{padding-bottom:40px}.hub .art-head{max-width:var(--maxw)}.hub .prose,.hub .facts{max-width:var(--maxw)}
.hub-list{margin:20px 0 10px}.hub-list h2{font-size:1.3rem}
/* home */
.hero{background:radial-gradient(ellipse at top,#1b1f3a,#0c0e18 70%);color:#eceef7;padding:48px 0 40px}
.hero h1{color:#fff;max-width:820px}.hero .lede{color:#aab0d6;max-width:720px}.hero .kicker{color:#fbbf24}
.hero-stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:12px;margin:24px 0;max-width:820px}
.hero-stats div{background:rgba(255,255,255,.04);border:1px solid #2a2f48;border-radius:var(--radius);padding:12px 14px}
.hero-stats strong{display:block;font-size:1.5rem;color:#fbbf24;font-variant-numeric:tabular-nums}.hero-stats span{font-size:.85rem;color:#aab0d6}
.hero-cta .btn{margin:4px 8px 4px 0}.hero .btn.ghost{color:#eceef7}
.home-sec{margin:36px 0}.home-sec h2{font-size:1.4rem;margin:0 0 14px}
.home-prose{max-width:var(--maxw)}
/* tools */
.tool{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:18px;margin:18px 0}
.tool-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:12px}
.tool label{display:block;font-size:.85rem;font-weight:650;margin-bottom:4px}
.tool input,.tool select{width:100%;font:inherit;padding:8px 10px;border:1px solid var(--line);border-radius:8px;background:var(--bg);color:var(--ink)}
.tool input:focus,.tool select:focus{outline:2px solid var(--brand);outline-offset:1px}
.tool-out{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px;margin-top:16px}
.tool-out div{background:var(--surface-2);border-radius:8px;padding:10px 12px}
.tool-out span{display:block;font-size:.78rem;color:var(--muted)}.tool-out strong{font-size:1.3rem;font-variant-numeric:tabular-nums}
.tool-err{color:var(--warn);font-size:.9rem;min-height:1.2em;margin:8px 0 0}
.action-big{font-size:2rem!important;color:var(--accent)}
.share{font-size:.85rem;margin-top:10px}
.bs-chart td,.bs-chart th{text-align:center;padding:4px 2px;font-size:.78rem;min-width:28px}
.a-H{background:#fde68a33}.a-S{background:#86efac33}.a-D,.a-Ds{background:#93c5fd44}.a-P{background:#f9a8d444}
/* footer */
.site-footer{background:#0c0e18;color:#aab0d6;margin-top:40px;padding:36px 0 20px;font-size:.92rem}
.site-footer a{color:#d6d9ea}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:24px}
@media (max-width:760px){.footer-grid{grid-template-columns:1fr}}
.foot-h{font-size:.85rem;text-transform:uppercase;letter-spacing:.07em;color:#fbbf24;margin:0 0 8px}
.site-footer ul{list-style:none;padding:0;margin:0}.site-footer li{margin:4px 0}
.age{border:1px solid #2a2f48;border-radius:8px;padding:10px 12px}
.foot-legal{border-top:1px solid #22263a;margin-top:24px;padding-top:14px;font-size:.82rem;color:#8a90b0}
@media (max-width:560px){body{font-size:16px}.nav{gap:2px 14px}.header-inner{padding:8px 20px}}