:root{
    --bg:#f5f7fb; --card:#ffffff; --ink:#161a2b; --muted:#525a70; --line:#e2e5ef;
    --accent:#2457d6; --accent-soft:#eaf0ff; --teal:#0e7490;
    --green:#137a37; --red:#b3342a; --amber:#8a5200; --example:#0b5394;
    --code:#eef1f8; --code-ink:#1f2438; --shadow:0 1px 3px rgba(15,20,50,.08);
  }
  *{box-sizing:border-box}
  html{scroll-behavior:smooth}
  body{margin:0;background:var(--bg);color:var(--ink);
       font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
       line-height:1.65;font-size:16px}
  a{color:var(--accent)}
  a:hover{text-decoration:underline}
  :focus-visible{outline:3px solid #7aa2ff;outline-offset:2px;border-radius:4px}
  .skip{position:absolute;left:-9999px;top:0;background:#fff;padding:10px 14px;z-index:100;border-radius:0 0 8px 0}
  .skip:focus{left:0}

  .layout{display:grid;grid-template-columns:310px minmax(0,1fr);max-width:1440px;margin:0 auto}

  nav.toc{position:sticky;top:0;align-self:start;height:100vh;overflow:auto;
          background:#12162a;color:#dde3f5;padding:22px 16px 60px}
  nav.toc .toc-title{font-size:15px;text-transform:uppercase;letter-spacing:.09em;color:#a7b0d6;margin:0 0 4px}
  nav.toc .toc-sub{font-size:12.5px;color:#7f88ad;margin:0 0 16px}
  nav.toc a{display:block;color:#c8cee8;text-decoration:none;font-size:13.5px;padding:3px 9px;border-radius:6px;border-left:3px solid transparent}
  nav.toc a:hover{background:#222848;color:#fff}
  nav.toc a.active{background:#26305a;color:#fff;border-left-color:#7aa2ff}
  nav.toc .grp{margin:16px 0 4px;font-size:11px;text-transform:uppercase;letter-spacing:.11em;color:#7d86ad;padding-left:9px}

  main{padding:34px 48px 140px;min-width:0;max-width:1000px}
  h1{font-size:33px;line-height:1.2;margin:0 0 6px}
  .sub{color:var(--muted);font-size:17px;margin:0 0 14px}
  .meta{font-size:13px;color:var(--muted);border-bottom:1px solid var(--line);padding-bottom:18px;margin-bottom:8px}
  h2{font-size:24px;margin:46px 0 12px;padding-left:13px;border-left:5px solid var(--accent);scroll-margin-top:14px}
  h3{font-size:18.5px;margin:28px 0 6px;color:#20253c;scroll-margin-top:14px}
  h4{font-size:16px;margin:20px 0 4px;color:#20253c}
  p{margin:10px 0}
  ul,ol{margin:10px 0 10px 24px;padding:0}
  li{margin:5px 0}
  code{background:var(--code);color:var(--code-ink);padding:1px 6px;border-radius:5px;
       font-family:"Cascadia Mono",Consolas,monospace;font-size:13.5px;white-space:nowrap}
  .card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:6px 24px 20px;margin:16px 0;box-shadow:var(--shadow)}
  .card > h2{border:0;padding-left:0;font-size:20px;margin:18px 0 4px}
  .lead{font-size:17px}

  .tip,.warn,.example,.note{border-radius:12px;padding:13px 17px;margin:16px 0;border-left:6px solid;font-size:15px}
  .tip{background:#eafaf0;border-color:var(--green)}
  .warn{background:#fff5e6;border-color:var(--amber)}
  .example{background:#eef6ff;border-color:var(--example)}
  .note{background:#f1f3f9;border-color:#98a0b8}
  .tip b,.warn b,.example b,.note b{display:block;margin-bottom:2px}

  table{width:100%;border-collapse:collapse;margin:14px 0;font-size:14.5px;background:var(--card);box-shadow:var(--shadow);border-radius:10px;overflow:hidden}
  caption{text-align:left;font-size:13px;color:var(--muted);padding:0 0 6px}
  th,td{border:1px solid var(--line);padding:9px 11px;text-align:left;vertical-align:top}
  th{background:#eef1f9;font-weight:600}
  tbody tr:nth-child(even){background:#fafbfe}
  .table-wrap{overflow-x:auto}

  figure{margin:20px 0;background:var(--card);border:1px solid var(--line);border-radius:14px;
         padding:10px;box-shadow:var(--shadow)}
  figure img{display:block;width:100%;height:auto;border-radius:9px;border:1px solid #dfe3ee}
  figcaption{font-size:13.5px;color:var(--muted);padding:10px 4px 2px}
  figcaption b{color:var(--ink)}

  .steps{counter-reset:s;list-style:none;margin-left:0}
  .steps>li{counter-increment:s;position:relative;padding:11px 0 11px 46px;border-bottom:1px dashed var(--line)}
  .steps>li:last-child{border-bottom:0}
  .steps>li:before{content:counter(s);position:absolute;left:0;top:9px;width:31px;height:31px;border-radius:50%;
      background:var(--accent);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px}

  kbd{background:#eef0f6;border:1px solid #c9cfe2;border-bottom-width:2px;border-radius:6px;padding:1px 7px;
      font-family:inherit;font-size:13px;color:#222;white-space:nowrap}
  .pill{display:inline-block;background:var(--accent);color:#fff;border-radius:999px;padding:1px 10px;font-size:12.5px;font-weight:600}
  .pill.alt{background:var(--teal)}
  .pill.ghost{background:var(--accent-soft);color:var(--accent)}
  .small{font-size:13.5px;color:var(--muted)}
  .two{display:grid;grid-template-columns:1fr 1fr;gap:16px}
  .path{color:var(--muted)}
  .path b{color:var(--ink)}
  .backtop{display:inline-block;font-size:12.5px;margin-top:6px}
  .sr{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
  .grid-cards{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:14px 0}
  .mini-card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:4px 16px 12px;box-shadow:var(--shadow)}
  .mini-card h4{margin-top:14px}
  .hl-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin:20px 0}
  .hl-card{position:relative;display:block;text-decoration:none;color:inherit;background:var(--card);
    border:1px solid var(--line);border-radius:14px;padding:18px 44px 18px 20px;box-shadow:var(--shadow);
    transition:transform .16s ease,box-shadow .16s ease,border-color .16s ease}
  .hl-card::before{content:"";position:absolute;left:-1px;top:16px;bottom:16px;width:3px;border-radius:3px;
    background:var(--accent);transform:scaleY(0);transform-origin:top;transition:transform .18s ease}
  .hl-card:hover,.hl-card:focus-visible{text-decoration:none;transform:translateY(-2px);border-color:#c7d5ff;
    box-shadow:0 8px 22px rgba(20,30,80,.10)}
  .hl-card:hover::before,.hl-card:focus-visible::before{transform:scaleY(1)}
  .hl-icon{width:38px;height:38px;border-radius:11px;background:var(--accent-soft);color:var(--accent);
    display:flex;align-items:center;justify-content:center;margin-bottom:12px}
  .hl-icon svg{width:20px;height:20px}
  .hl-card h4{margin:0 0 6px;font-size:16px;color:#1b2035;transition:color .16s ease}
  .hl-card:hover h4,.hl-card:focus-visible h4{color:var(--accent)}
  .hl-card p{margin:0;font-size:14px;line-height:1.55;color:var(--muted)}
  .hl-arrow{position:absolute;top:18px;right:16px;color:var(--muted);opacity:.35;
    transition:transform .16s ease,opacity .16s ease,color .16s ease}
  .hl-arrow svg{width:18px;height:18px}
  .hl-card:hover .hl-arrow,.hl-card:focus-visible .hl-arrow{opacity:1;color:var(--accent);transform:translateX(3px)}
  @media(max-width:980px){
    .layout{grid-template-columns:1fr}
    nav.toc{position:relative;height:auto;max-height:none}
    main{padding:24px}
    .two,.grid-cards,.hl-grid{grid-template-columns:1fr}
  }
  @media print{
    nav.toc,.top,.skip{display:none}
    .layout{display:block;max-width:none}
    main{padding:0;max-width:none}
    figure,.card,.tip,.warn,.example,.note,table,.hl-card{box-shadow:none;break-inside:avoid}
    .hl-arrow{display:none}
    a{color:inherit;text-decoration:none}
  }