:root {
    --bg: #ffffff; --text: #1a1a2e; --text-dim: #55566b;
    --accent: #0a6cd4; --accent-dark: #0851a3; --card-bg: #eaf3fd; --border: #cfe2f7;
    --ok: #1a8a4a; --ok-bg: #e7f7ee; --bad: #c0392b; --bad-bg: #fceceb; --warn: #a86b00; --warn-bg: #fdf3df;
  }
  @media (prefers-color-scheme: dark) {
    :root {
      --bg: #0c1420; --text: #eaf1fa; --text-dim: #a3b3c9;
      --accent: #6ab0ff; --accent-dark: #4a8ed9; --card-bg: #131e2c; --border: #223347;
      --ok: #4ad080; --ok-bg: #17301f; --bad: #ff7a68; --bad-bg: #341c1a; --warn: #e0ad4d; --warn-bg: #362a12;
    }
  }
  * { box-sizing: border-box; }
  body { margin: 0; background: var(--bg); color: var(--text); font-family: "Inter", system-ui, sans-serif; line-height: 1.65; }
  .wrap { max-width: 760px; margin: 0 auto; padding: 2.5rem 1.25rem 5rem; }
  h1 { font-size: clamp(1.6rem, 5vw, 2.3rem); font-weight: 800; line-height: 1.2; margin: 0 0 0.5rem; }
  .kicker { color: var(--accent-dark); font-weight: 700; font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.04em; margin-bottom: 0.5rem; }
  @media (prefers-color-scheme: dark) { .kicker { color: var(--accent); } }
  h2 { font-size: 1.4rem; font-weight: 800; margin: 2.5rem 0 0.8rem; }
  h3 { font-size: 1.1rem; font-weight: 700; margin: 1.6rem 0 0.6rem; }
  p { margin: 0 0 1rem; }
  .lede { font-size: 1.1rem; color: var(--text-dim); }
  a { color: var(--accent-dark); } @media (prefers-color-scheme: dark) { a { color: var(--accent); } }
  .card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 12px; padding: 1.25rem 1.4rem; margin: 1.5rem 0; }
  .flag { font-size: 0.85rem; color: var(--warn); background: var(--warn-bg); border-radius: 8px; padding: 0.5rem 0.8rem; display: inline-block; margin: 0.4rem 0; }
  ul, ol { padding-left: 1.3rem; }
  li { margin-bottom: 0.5rem; }
  table { border-collapse: collapse; width: 100%; font-size: 0.9rem; min-width: 480px; }
  th, td { text-align: left; padding: 0.5rem 0.65rem; border-bottom: 1px solid var(--border); }
  th { color: var(--text-dim); font-weight: 700; }
  .table-scroll { overflow-x: auto; margin: 1rem 0; -webkit-overflow-scrolling: touch; }
  .figure { margin: 1.6rem 0; }
  .caption { font-size: 0.82rem; color: var(--text-dim); margin-top: 0.5rem; }
  svg { max-width: 100%; height: auto; display: block; }
  button { font-family: inherit; font-size: 0.9rem; font-weight: 600; cursor: pointer; border-radius: 8px; border: 1px solid var(--border); background: var(--card-bg); color: var(--text); padding: 0.5rem 0.9rem; }
  button:hover { border-color: var(--accent); }
  button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
  label { font-size: 0.85rem; font-weight: 600; color: var(--text-dim); display: block; margin-bottom: 0.3rem; }
  input[type="range"] { width: 100%; accent-color: var(--accent); }
  .calc-row { display: grid; grid-template-columns: 1fr; gap: 1rem; }
  .quiz-opt { display: block; width: 100%; text-align: left; margin: 0.4rem 0; }
  .quiz-opt.chosen-ok { background: var(--ok-bg); border-color: var(--ok); color: var(--ok); }
  .quiz-opt.chosen-bad { background: var(--bad-bg); border-color: var(--bad); color: var(--bad); }
  .quiz-explain { font-size: 0.88rem; margin-top: 0.6rem; padding: 0.6rem 0.8rem; border-radius: 8px; display: none; }
  .quiz-explain.show { display: block; }
  .tldr { background: var(--card-bg); border: 1px solid var(--accent); border-radius: 12px; padding: 1.2rem 1.4rem; }
  footer { margin-top: 3rem; padding-top: 1.5rem; border-top: 1px solid var(--border); font-size: 0.85rem; color: var(--text-dim); }
  .stat-out { font-size: 1.4rem; font-weight: 800; color: var(--accent-dark); }
  @media (prefers-color-scheme: dark) { .stat-out { color: var(--accent); } }
  @media (prefers-reduced-motion: reduce) { * { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; } }
  .breadcrumbs { font-size: 0.78rem; color: var(--text-dim); margin-bottom: 0.9rem; display: flex; flex-wrap: wrap; align-items: center; gap: 0.15rem; }
  .breadcrumbs a { color: var(--text-dim); text-decoration: none; }
  .breadcrumbs a:hover { text-decoration: underline; color: var(--accent-dark); }
  @media (prefers-color-scheme: dark) { .breadcrumbs a:hover { color: var(--accent); } }
  .breadcrumbs [aria-current] { color: var(--text); font-weight: 600; }
  .updated { font-size: 0.85rem; color: var(--text-dim); margin: 0 0 1rem; }
  .page-meta { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 0.8rem; margin: 0 0 1.2rem; padding: 0.7rem 0; border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
  .byline { display: inline-flex; align-items: center; gap: 0.55rem; text-decoration: none; color: var(--text); }
  .byline img { width: 30px; height: 30px; border-radius: 50%; object-fit: cover; display: block; }
  .byline span { font-size: 0.85rem; line-height: 1.3; }
  .byline strong { display: block; font-weight: 700; }
  .byline .role { color: var(--text-dim); font-weight: 400; }
  .share-top { display: flex; align-items: center; gap: 0.5rem; font-size: 0.8rem; }
  .share-top .label { color: var(--text-dim); font-weight: 600; }
  .share-top a { color: var(--text-dim); text-decoration: none; padding: 0.25rem 0.55rem; border: 1px solid var(--border); border-radius: 6px; }
  .share-top a:hover { color: var(--text); border-color: var(--accent); }
  .toc { background: var(--card-bg); border: 1px solid var(--border); border-radius: 12px; padding: 0.9rem 1.1rem; margin: 0 0 1.6rem; }
  .toc summary { cursor: pointer; font-weight: 700; font-size: 0.92rem; }
  .toc ol { margin: 0.7rem 0 0; padding-left: 1.2rem; columns: 1; }
  .toc li { margin-bottom: 0.4rem; font-size: 0.87rem; }
  .toc a { color: var(--text-dim); text-decoration: none; }
  .toc a:hover { color: var(--accent-dark); text-decoration: underline; }
  @media (prefers-color-scheme: dark) { .toc a:hover { color: var(--accent); } }
  @media (min-width: 640px) { .toc ol { columns: 2; column-gap: 1.5rem; } }
  .checklist { list-style:none; padding-left:0.2rem; }
  pre { background: var(--bg-soft, rgba(127,127,127,0.08)); border:1px solid var(--border); border-radius:10px; padding:0.9rem 1rem; overflow-x:auto; white-space:pre-wrap; font-size:0.85rem; line-height:1.5; }
  .checklist li::before { content:"\2610"; margin-right:0.55rem; color: var(--accent-dark); }