:root{
  --bg:#f7f8fc; --bg2:#ffffff; --ink:#0f172a; --muted:#51607a; --line:#e2e6f0;
  --brand:#5b5ff0; --brand2:#12b3a2; --brand-ink:#ffffff; --card:#ffffff;
  --code-bg:#0f172a; --code-ink:#e6edf7; --warn-bg:#fff7e6; --warn-line:#f2c46b; --warn-ink:#5c3d00;
  --shadow:0 1px 2px rgba(15,23,42,.05),0 8px 30px rgba(15,23,42,.06);
  --radius:18px;
}
@media (prefers-color-scheme:dark){
  :root{
    --bg:#0b1020; --bg2:#10172b; --ink:#e8ecf8; --muted:#9aa7c4; --line:#222c47;
    --brand:#8b8ffa; --brand2:#2dd4bf; --brand-ink:#0b1020; --card:#121a31;
    --code-bg:#070b17; --code-ink:#dbe4f5; --warn-bg:#2a2210; --warn-line:#6b5316; --warn-ink:#f3dca0;
    --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 30px rgba(0,0,0,.35);
  }
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:76px}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;-webkit-font-smoothing:antialiased}
.wrap{width:min(1040px,100% - 32px);margin-inline:auto}
a{color:var(--brand)}
h1,h2,h3{line-height:1.15;letter-spacing:-.02em;margin:0}

.nav{position:sticky;top:0;z-index:10;background:color-mix(in srgb,var(--bg) 82%,transparent);backdrop-filter:saturate(1.4) blur(12px);border-bottom:1px solid var(--line)}
.nav-in{display:flex;align-items:center;justify-content:space-between;height:60px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-weight:500}
.brand b{font-weight:700}
.lang{display:flex;background:var(--bg2);border:1px solid var(--line);border-radius:999px;padding:3px}
.lang button{border:0;background:none;color:var(--muted);font:600 13px/1 inherit;padding:7px 12px;border-radius:999px;cursor:pointer}
.lang button[aria-pressed="true"]{background:var(--ink);color:var(--bg)}

.hero{position:relative;padding:84px 0 72px;text-align:center;overflow:hidden}
.hero::before{content:"";position:absolute;inset:-20% -10% auto;height:560px;z-index:-1;
  background:radial-gradient(500px 280px at 25% 30%,color-mix(in srgb,var(--brand) 28%,transparent),transparent 70%),
             radial-gradient(520px 300px at 78% 20%,color-mix(in srgb,var(--brand2) 26%,transparent),transparent 70%)}
.pill{display:inline-block;margin:0 0 22px;padding:6px 14px;border:1px solid var(--line);background:var(--bg2);border-radius:999px;font-size:13px;font-weight:600;color:var(--muted)}
.hero h1{font-size:clamp(34px,6vw,62px);font-weight:800;max-width:17ch;margin-inline:auto}
.grad{background:linear-gradient(100deg,var(--brand),var(--brand2));-webkit-background-clip:text;background-clip:text;color:transparent}
.lead{max-width:60ch;margin:22px auto 0;font-size:clamp(17px,2.2vw,20px);color:var(--muted)}
.cta{display:flex;flex-wrap:wrap;gap:12px;justify-content:center;margin-top:32px}
.btn{display:inline-block;padding:13px 22px;border-radius:12px;font-weight:650;text-decoration:none;transition:transform .15s,box-shadow .15s}
.btn:hover{transform:translateY(-1px)}
.btn.primary{background:linear-gradient(100deg,var(--brand),var(--brand2));color:var(--brand-ink);box-shadow:0 8px 24px color-mix(in srgb,var(--brand) 35%,transparent)}
.btn.ghost{border:1px solid var(--line);background:var(--bg2);color:var(--ink)}
.badges{display:flex;flex-wrap:wrap;gap:8px 20px;justify-content:center;list-style:none;margin:34px 0 0;padding:0;color:var(--muted);font-size:14px;font-weight:600}
.badges li::before{content:"✓";color:var(--brand2);margin-right:8px;font-weight:800}

.block{padding:56px 0}
.block h2{font-size:clamp(26px,4vw,38px);font-weight:800}
.sub{color:var(--muted);margin:10px 0 0;max-width:62ch}

.diagram{margin:30px 0 0;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}
.diagram svg{width:100%;height:auto;display:block}
.d-zone{fill:color-mix(in srgb,var(--brand) 6%,transparent);stroke:var(--line);stroke-width:1.5;stroke-dasharray:0}
.d-zonelabel{fill:var(--muted);font:600 14px system-ui,sans-serif;letter-spacing:.04em;text-transform:uppercase}
.d-box{fill:var(--bg2);stroke:var(--line);stroke-width:1.5}
.d-box.accent{fill:color-mix(in srgb,var(--brand2) 14%,var(--bg2));stroke:var(--brand2)}
.d-box.dashed{stroke-dasharray:6 5;fill:transparent}
.d-title{fill:var(--ink);font:700 19px system-ui,sans-serif}
.d-small{fill:var(--muted);font:500 14px system-ui,sans-serif}
.d-line{fill:none;stroke:var(--muted);stroke-width:2}
.d-line.dashed{stroke-dasharray:4 4}
.d-arrowhead{fill:var(--muted)}
.d-x circle{fill:#ef4444}
.d-x path{stroke:#fff;stroke-width:2.2;stroke-linecap:round}

.steps{list-style:none;padding:0;margin:30px 0 0;display:grid;gap:18px}
.steps>li{display:grid;grid-template-columns:48px 1fr;gap:18px;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow)}
.num{width:48px;height:48px;border-radius:14px;display:grid;place-items:center;font-weight:800;font-size:20px;color:var(--brand-ink);background:linear-gradient(135deg,var(--brand),var(--brand2))}
.body{min-width:0}
.body h3{font-size:21px;margin-bottom:8px}
.body p{margin:8px 0;color:var(--muted)}
.link{font-weight:600}
.note{font-size:14px;border-left:3px solid var(--brand2);padding-left:12px;color:var(--muted)}
blockquote{margin:12px 0 0;padding:14px 18px;border-radius:12px;background:var(--bg);border:1px solid var(--line);font-style:italic}

.tabs{display:inline-flex;gap:4px;background:var(--bg);border:1px solid var(--line);border-radius:12px;padding:4px;margin:6px 0 10px}
.tabs button{border:0;background:none;color:var(--muted);font:600 14px/1 inherit;padding:10px 16px;border-radius:9px;cursor:pointer}
.tabs button[aria-selected="true"]{background:var(--card);color:var(--ink);box-shadow:var(--shadow)}
.codebox{position:relative;margin:10px 0}
.codebox pre{margin:0;background:var(--code-bg);color:var(--code-ink);border-radius:14px;padding:18px 18px;padding-right:96px;overflow-x:auto;font:13.5px/1.6 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;white-space:pre}
.copy{position:absolute;top:10px;right:10px;border:1px solid rgba(255,255,255,.18);background:rgba(255,255,255,.08);color:#fff;font:600 12.5px/1 inherit;padding:8px 12px;border-radius:9px;cursor:pointer}
.copy:hover{background:rgba(255,255,255,.16)}
.copy.done{background:var(--brand2);border-color:var(--brand2);color:#04211d}

.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(290px,1fr));gap:16px;margin-top:28px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow)}
.card h3{font-size:18px;margin-bottom:8px}
.card p{margin:0;color:var(--muted)}
.callout{margin-top:20px;background:var(--warn-bg);border:1px solid var(--warn-line);color:var(--warn-ink);border-radius:var(--radius);padding:18px 22px}
.callout p{margin:6px 0 0}

details{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:4px 20px;margin-top:12px}
summary{cursor:pointer;font-weight:650;padding:14px 0;list-style:none;display:flex;justify-content:space-between;gap:16px}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";font-size:22px;line-height:1;color:var(--muted)}
details[open] summary::after{content:"−"}
details p{margin:0 0 16px;color:var(--muted)}

.foot{margin-top:40px;padding:34px 0 48px;border-top:1px solid var(--line);color:var(--muted);font-size:14px}
.foot p{margin:0;max-width:70ch}
:focus-visible{outline:3px solid var(--brand);outline-offset:2px;border-radius:6px}

@media (max-width:640px){
  .hero{padding:56px 0 48px}
  .steps>li{grid-template-columns:1fr;padding:20px}
  .num{width:40px;height:40px;font-size:17px}
  .brand span{font-size:15px}
}

.dl{display:inline-flex;flex-direction:column;align-items:flex-start;gap:2px;margin:6px 0 4px;text-align:left}
.dl small{font-weight:500;opacity:.85;font-size:12.5px}
.mini{margin:14px 0 4px;padding-left:22px;color:var(--muted)}
.mini li{margin:6px 0}
.sha{font-size:13px;word-break:break-all}
.sha code,.note code{font:12.5px ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;background:var(--bg);border:1px solid var(--line);border-radius:6px;padding:2px 6px}

.nav-right{display:flex;align-items:center;gap:16px}
.navlink{color:var(--muted);text-decoration:none;font-weight:600;font-size:14px}
.navlink:hover{color:var(--ink)}
.dochead{padding:56px 0 8px}
.dochead h1{font-size:clamp(32px,5vw,48px);font-weight:800}
.lead.left{margin:14px 0 0;max-width:62ch}
.toc{display:flex;flex-wrap:wrap;gap:8px;margin-top:24px}
.toc a{padding:8px 14px;border:1px solid var(--line);border-radius:999px;background:var(--bg2);color:var(--ink);text-decoration:none;font-size:14px;font-weight:600}
.toc a:hover{border-color:var(--brand)}
.doc{padding:36px 0}
.doc h2{font-size:clamp(22px,3.2vw,30px);margin-bottom:12px}
.doc p{color:var(--muted);max-width:72ch}
ul.plain{padding-left:20px;max-width:72ch;color:var(--muted)}
ul.plain li{margin:10px 0}
ul.ex{padding-left:18px;margin:0;color:var(--muted)}
ul.ex li{margin:8px 0}
.grp{font-size:18px;margin:26px 0 12px}
.tools{display:grid;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:12px}
.tool{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px 16px}
.tool h4{margin:0 0 6px;font-size:15px;display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.tool h4 code{font:600 14px ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}
.tool p{margin:4px 0;font-size:14px;color:var(--muted)}
.tool .params code{font:12.5px ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;background:var(--bg);border:1px solid var(--line);border-radius:6px;padding:1px 6px;margin-right:4px;display:inline-block;margin-bottom:4px}
.tag{font:700 11px/1 system-ui,sans-serif;text-transform:uppercase;letter-spacing:.05em;padding:4px 7px;border-radius:999px;background:color-mix(in srgb,var(--brand2) 18%,transparent);color:var(--ink)}
.tag.write{background:color-mix(in srgb,var(--brand) 22%,transparent)}
.tag.delete{background:#fde2e2;color:#7a1212}
@media (prefers-color-scheme:dark){.tag.delete{background:#4a1b1b;color:#ffd3d3}}
.doc code{font:13px ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;background:var(--bg2);border:1px solid var(--line);border-radius:6px;padding:1px 6px}