/* Text version of each lesson (washer/, fridge/, en/…, ja/…) and the not-found page (404.html).
 * The course page's dark tokens (css/app.css), system fonts only (no web fonts, no
 * requests), a readable measure, 16px side gutters and no sideways scroll at 360px. */

:root {
  --bg: #0a0e17;
  --bg-2: #111827;
  --ink: #e9eef6;
  --ink-2: #aab4c3;
  --ink-3: #6f7b8d;
  --line: rgba(170, 190, 220, 0.14);
  --line-2: rgba(170, 190, 220, 0.26);
  --brand: #0ea9e2;
  --brand-ink: #7fd6f6;
  --brand-soft: rgba(14, 169, 226, 0.14);
  --sans: "PingFang HK", "PingFang TC", "Microsoft JhengHei", "Noto Sans TC", "Noto Sans CJK TC", system-ui, sans-serif;
  --math: "Times New Roman", "Noto Serif", Georgia, serif;
  --measure: 44rem;
  color-scheme: dark;
}
html[lang="en"] { --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; }
html[lang="ja"] { --sans: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic UI", "Yu Gothic", Meiryo, "Noto Sans JP", "Noto Sans CJK JP", system-ui, sans-serif; }
[lang="zh-Hant-HK"] { font-family: "PingFang HK", "PingFang TC", "Microsoft JhengHei", "Noto Sans TC", "Noto Sans CJK TC", system-ui, sans-serif; }

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.75 var(--sans);
  overflow-wrap: break-word;
  /* The site chat button sits bottom right on every page: the last lines scroll clear of it. */
  padding-bottom: 96px;
}
html[lang="en"] body { line-height: 1.65; }

a { color: var(--brand-ink); text-underline-offset: 0.18em; }
a:hover { color: #aee6fb; }
a:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; border-radius: 4px; }
b { font-weight: 700; color: #fff; }
i { font-family: var(--math); font-size: 1.05em; }
sub, sup { line-height: 0; }

/* Top bar: logo and languages on one row, the 3D link beside them where it fits. */
.top {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 16px;
  max-width: calc(var(--measure) + 32px);
  margin: 0 auto;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
}
.logo { display: block; line-height: 0; }
.logo img { width: 107px; height: auto; }
.langs { display: flex; gap: 2px; margin-left: auto; padding: 3px; border: 1px solid var(--line-2); border-radius: 999px; }
.langs a {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 0 10px;
  border-radius: 999px;
  color: var(--ink-2);
  text-decoration: none;
  font-size: 14px;
  white-space: nowrap;
}
.langs a[aria-current="page"] { background: var(--brand-soft); color: var(--ink); }
.open3d {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0 16px;
  border-radius: 999px;
  background: var(--brand);
  color: #04121a;
  font-weight: 700;
  font-size: 14px;
  text-decoration: none;
}
.open3d:hover { color: #04121a; background: #3dbce9; }
@media (max-width: 520px) {
  .open3d { flex: 1 1 100%; justify-content: center; }
}

main, footer { max-width: calc(var(--measure) + 32px); margin: 0 auto; padding: 0 16px; }

.crumbs { margin: 18px 0 0; font-size: 13.5px; color: var(--ink-3); }
.crumbs a { color: var(--ink-2); }
h1 { margin: 10px 0 12px; font-size: 30px; line-height: 1.25; letter-spacing: 0.01em; }
h1 em { font-style: normal; color: var(--brand-ink); }
html[lang="zh-Hant-HK"] h1 em { margin-left: 0.15em; }
.lede { margin: 0 0 14px; font-size: 17px; color: var(--ink-2); }
.note {
  margin: 0 0 8px;
  padding: 10px 14px;
  border-left: 3px solid var(--brand);
  border-radius: 0 10px 10px 0;
  background: var(--bg-2);
  font-size: 14.5px;
  color: var(--ink-2);
}

h2 { margin: 40px 0 10px; font-size: 22px; line-height: 1.35; }
h3 { margin: 26px 0 6px; font-size: 17px; line-height: 1.45; color: var(--brand-ink); }
p { margin: 0 0 12px; }
section { scroll-margin-top: 12px; }

.toc { margin: 24px 0 0; padding: 4px 18px 10px; border: 1px solid var(--line); border-radius: 14px; background: var(--bg-2); }
.toc h2 { margin: 12px 0 6px; font-size: 15px; color: var(--ink-2); }
.toc ol, .toc ul { margin: 0; padding-left: 1.5em; }
.toc ul { margin-top: 6px; list-style: none; padding-left: 0; }
.toc li { margin: 3px 0; }

.chapter h3 { color: var(--ink-2); font-size: 15px; letter-spacing: 0.02em; }
.chapter h3 + p, .chapter h3 ~ p { color: var(--ink-2); }

.fault { margin: 0 0 8px; }
.fault dl { margin: 0; }
.fault dt { margin-top: 8px; font-size: 13.5px; font-weight: 700; color: var(--ink-3); letter-spacing: 0.04em; }
.fault dd { margin: 0; }
.repair { margin-top: 8px; font-size: 14.5px; color: var(--ink-2); }

.parts-in { font-size: 14.5px; color: var(--ink-2); }
.parts dl { margin: 0; }
.parts dt { margin-top: 16px; font-weight: 700; color: var(--brand-ink); }
.parts dd { margin: 2px 0 0; }

footer { margin-top: 48px; padding-top: 18px; border-top: 1px solid var(--line); font-size: 14.5px; color: var(--ink-2); }
footer small { display: block; color: var(--ink-3); font-size: 13px; }
.pub { color: var(--ink-3); }

/* 404.html: the same page in three languages, one section each. */
.nf section { padding: 22px 0 6px; }
.nf section + section { border-top: 1px solid var(--line); }
.nf h1, .nf h2 { margin: 0 0 6px; font-size: 22px; line-height: 1.35; }
.nf ul { margin: 0 0 12px; padding-left: 1.2em; }
.nf li { margin: 6px 0; }
.nf small { margin-left: 0.3em; color: var(--ink-3); font-size: 13px; }

@media (min-width: 900px) {
  h1 { font-size: 36px; }
  body { font-size: 17px; }
}