:root {
  --bg: #f6f7f9;
  --card: #fff;
  --text: #1a1d21;
  --muted: #5c6570;
  --accent: #0b5fff;
  --accent-soft: #e8f0ff;
  --border: #d8dee6;
  --warn: #8a4b00;
  --warn-bg: #fff6e8;
  --ok: #0d6b3a;
  --ok-bg: #e8f7ef;
  --branch: #f0f3f7;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.55;
  color: var(--text);
  background: var(--bg);
}
a { color: var(--accent); }
a:hover { text-decoration: underline; }
.skip {
  position: absolute; left: -9999px;
}
.skip:focus { left: 1rem; top: 1rem; background: #000; color: #fff; padding: .5rem 1rem; z-index: 99; }
.wrap { max-width: 1100px; margin: 0 auto; padding: 0 1rem; }
.site-header { background: #0f172a; color: #fff; padding: 1rem 0; }
.site-header a { color: #fff; text-decoration: none; font-weight: 700; font-size: 1.15rem; }
.tag { margin: .25rem 0 0; color: #cbd5e1; font-size: .9rem; }
.site-nav { background: #fff; border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 10; }
.nav-scroll { display: flex; gap: .5rem; overflow-x: auto; padding: .6rem 1rem; }
.site-nav a {
  white-space: nowrap; text-decoration: none; color: var(--text);
  padding: .35rem .7rem; border-radius: 999px; font-size: .88rem; border: 1px solid transparent;
}
.site-nav a.active, .site-nav a:hover { background: var(--accent-soft); border-color: #c5d8ff; }
.layout { display: grid; grid-template-columns: 220px 1fr; gap: 1.5rem; padding: 1.5rem 1rem 3rem; }
.toc {
  position: sticky; top: 3.5rem; align-self: start;
  background: var(--card); border: 1px solid var(--border); border-radius: 10px; padding: 1rem;
  font-size: .9rem;
}
.toc h2 { margin: 0 0 .5rem; font-size: .95rem; }
.toc ol { margin: 0; padding-left: 1.1rem; }
.toc li { margin: .35rem 0; }
main {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 1.25rem 1.4rem 2rem;
}
h1 { margin-top: 0; font-size: 1.75rem; line-height: 1.25; }
h2 { margin-top: 1.75rem; font-size: 1.25rem; border-top: 1px solid var(--border); padding-top: 1.25rem; }
h3 { font-size: 1.05rem; margin: 1.1rem 0 .4rem; }
.lead { font-size: 1.05rem; color: var(--muted); }
.callout {
  border-radius: 10px; padding: .9rem 1rem; margin: 1rem 0;
  border: 1px solid var(--border); background: var(--branch);
}
.callout.do-not-skip { background: var(--warn-bg); border-color: #f0c987; color: var(--warn); }
.callout.ok { background: var(--ok-bg); border-color: #9fd4b5; color: var(--ok); }
.steps { counter-reset: step; list-style: none; padding: 0; margin: 0; }
.steps > li {
  position: relative; padding: 1rem 1rem 1rem 3.2rem; margin: 0 0 .85rem;
  background: var(--branch); border-radius: 10px; border: 1px solid var(--border);
}
.steps > li::before {
  counter-increment: step; content: counter(step);
  position: absolute; left: .85rem; top: 1rem;
  width: 1.7rem; height: 1.7rem; border-radius: 50%;
  background: var(--accent); color: #fff; font-weight: 700; font-size: .9rem;
  display: flex; align-items: center; justify-content: center;
}
.branch-box {
  display: grid; gap: .6rem; margin: .75rem 0;
}
@media (min-width: 700px) {
  .branch-box.two { grid-template-columns: 1fr 1fr; }
}
.branch {
  background: #fff; border: 1px dashed var(--border); border-radius: 8px; padding: .75rem;
}
.branch strong { display: block; margin-bottom: .25rem; }
.symptom-map {
  display: grid; gap: .5rem;
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  list-style: none; padding: 0;
}
.symptom-map a {
  display: block; padding: .7rem .85rem; background: var(--accent-soft);
  border-radius: 8px; text-decoration: none; border: 1px solid #c5d8ff; color: var(--text);
  font-size: .92rem;
}
.symptom-map a:hover { border-color: var(--accent); }
.figure {
  margin: .75rem 0; padding: .5rem; background: #fff; border: 1px solid var(--border); border-radius: 8px;
}
.figure img { max-width: 100%; height: auto; display: block; background: #eef2f7; min-height: 140px; }
.figure figcaption { font-size: .85rem; color: var(--muted); margin-top: .4rem; }
.faq details {
  border: 1px solid var(--border); border-radius: 8px; padding: .6rem .85rem; margin: .5rem 0; background: #fff;
}
.faq summary { cursor: pointer; font-weight: 600; }
.sources ul { padding-left: 1.2rem; }
.disclaimer { font-size: .88rem; color: var(--muted); }
@media (max-width: 860px) {
  .layout { grid-template-columns: 1fr; }
  .toc { position: static; }
}

kbd {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .85em; background: #eef2f7; border: 1px solid var(--border);
  border-bottom-width: 2px; border-radius: 4px; padding: .1rem .35rem;
}