:root {
  color-scheme: light;
  --paper: #fff;
  --ink: #000;
  --body: #292929;
  --muted: #626262;
  --line: #dedede;
  --soft: #f5f5f5;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial,
    "PingFang TC", "Microsoft JhengHei UI", "Microsoft JhengHei", "Noto Sans TC", sans-serif;
  font-size: 100%;
  background: var(--paper);
  color: var(--body);
  scrollbar-color: #aaa var(--paper);
}
* { box-sizing: border-box; }
body { margin: 0; line-height: 1.8; }
::selection { color: var(--paper); background: var(--ink); }
a { color: inherit; text-underline-offset: .22em; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
a:focus-visible { outline: 2px solid var(--ink); outline-offset: 5px; border-radius: 2px; }
svg { display: block; flex-shrink: 0; }
h1, h2, h3, p { margin: 0; }
h1, h2, h3 { color: var(--ink); text-wrap: balance; }
h2 { font-size: clamp(1.35rem, 2.5vw, 1.75rem); font-weight: 650; line-height: 1.5; }
h3 { font-size: 1.125rem; font-weight: 650; line-height: 1.5; }
.site-header, main, .site-footer { width: min(100% - 80px, 1060px); margin-inline: auto; }
.site-header { display: flex; align-items: center; justify-content: space-between; min-height: 104px; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 12px; text-decoration: none; color: var(--ink); font-weight: 650; font-size: 1.125rem; }
.header-return { display: inline-flex; align-items: center; min-height: 44px; font-size: .9375rem; white-space: nowrap; }
.skip-link { position: absolute; left: 20px; top: 12px; z-index: 2; padding: 10px 16px; background: var(--ink); color: var(--paper); transform: translateY(-180%); }
.skip-link:focus { transform: translateY(0); }
.intro { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; padding-block: 68px 72px; align-items: start; }
h1 { font-size: clamp(2.25rem, 4.4vw, 3.5rem); line-height: 1.35; font-weight: 650; letter-spacing: -.025em; }
.intro-copy { max-width: 34rem; font-size: 1.0625rem; padding-top: 5px; }
.intro-copy p + p { margin-top: 14px; color: var(--muted); }
.primary-link { display: inline-flex; justify-content: center; align-items: center; min-height: 48px; padding: 10px 23px; border-radius: 12px; background: var(--ink); color: var(--paper); font-size: 1rem; font-weight: 600; text-decoration: none; }
.primary-link:hover { background: #292929; text-decoration: none; }
.primary-link:active { background: #444; }
.intro .primary-link { margin-top: 25px; }
.page-nav { display: flex; flex-wrap: wrap; column-gap: 32px; border-block: 1px solid var(--line); padding-block: 7px; }
.page-nav a { display: inline-flex; align-items: center; min-height: 44px; font-size: .9375rem; text-decoration: none; }
.page-nav a:hover { text-decoration: underline; }
.content-section { padding-top: 64px; scroll-margin-top: 24px; }
.section-heading p { margin-top: 10px; color: var(--muted); }
.steps { padding: 0; margin: 31px 0 0; list-style: none; counter-reset: steps; }
.steps li { counter-increment: steps; position: relative; padding: 0 0 27px 55px; max-width: 53rem; }
.steps li:last-child { padding-bottom: 0; }
.steps li::before { content: counter(steps); position: absolute; left: 0; top: -1px; width: 34px; height: 34px; display: grid; place-items: center; border: 1px solid #a5a5a5; border-radius: 50%; color: var(--ink); font-variant-numeric: tabular-nums; font-weight: 600; }
.steps p { margin-top: 7px; }
.camera-note { margin-top: 28px; padding: 17px 20px; border-radius: 12px; background: var(--soft); font-size: .9375rem; }
.demo-note { margin-top: 22px; max-width: 50rem; color: var(--muted); font-size: .9375rem; }
.vocabulary { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 32px; margin-top: 29px; }
.vocabulary h3 { display: flex; align-items: baseline; justify-content: space-between; flex-wrap: wrap; gap: 6px 12px; padding-bottom: 13px; border-bottom: 1px solid var(--line); }
.vocabulary h3 span { color: var(--muted); font-size: .8125rem; font-weight: 400; }
.word-list { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 12px; padding: 0; margin: 17px 0 0; list-style: none; }
.word-list li { min-width: 0; }
.notes { display: grid; gap: 25px; margin: 29px 0 0; max-width: 50rem; }
.notes dt { color: var(--ink); font-weight: 600; font-size: 1.0625rem; }
.notes dd { margin: 7px 0 0; }
.source-section { margin-top: 64px; padding-top: 35px; border-top: 1px solid var(--line); scroll-margin-top: 24px; }
.source-section h2 { font-size: 1.25rem; }
.source-section p { margin-top: 13px; max-width: 50rem; color: var(--muted); font-size: .9375rem; }
.source-section a { color: var(--body); }
.text-link { display: inline-flex; min-height: 44px; align-items: center; margin-top: 7px; font-size: .9375rem; }
.site-footer { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 18px 30px; padding-block: 38px 60px; }
.site-footer p { font-size: 1.0625rem; color: var(--ink); }
@media (max-width: 720px) {
  .site-header, main, .site-footer { width: calc(100% - 40px); }
  .site-header { min-height: 82px; gap: 16px; }
  .brand { gap: 9px; font-size: 1rem; }
  .brand svg { width: 27px; height: 27px; }
  .header-return { font-size: .875rem; }
  .intro { grid-template-columns: 1fr; gap: 24px; padding-block: 32px 40px; }
  h1 { font-size: clamp(2.125rem, 7.7vw, 3rem); }
  .intro-copy { font-size: 1rem; padding-top: 0; }
  .intro .primary-link { margin-top: 22px; }
  .page-nav { column-gap: 25px; }
  .page-nav a { font-size: .875rem; }
  .content-section { padding-top: 42px; }
  .steps { margin-top: 26px; }
  .steps li { padding-left: 47px; }
  .camera-note { padding: 16px; }
  .vocabulary { grid-template-columns: 1fr; gap: 28px; margin-top: 25px; }
  .vocabulary h3 { justify-content: flex-start; gap: 16px; }
  .word-list { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 9px 12px; }
  .source-section { margin-top: 44px; padding-top: 29px; }
  .site-footer { padding-block: 30px 42px; }
}
@media (max-width: 360px) {
  .site-header, main, .site-footer { width: calc(100% - 32px); }
  .brand { gap: 7px; font-size: .9375rem; }
  .header-return { font-size: .8125rem; }
  .page-nav { display: grid; grid-template-columns: 1fr 1fr; }
  .word-list { grid-template-columns: 1fr 1fr; }
}
@media print {
  .skip-link, .header-return, .page-nav, .primary-link, .site-footer { display: none; }
  .site-header, main { width: 100%; }
  .site-header { min-height: 60px; }
  .intro { padding-block: 24px; }
  .content-section { padding-top: 28px; }
  .steps li, .notes > div, .vocabulary > section { break-inside: avoid; }
  a { color: var(--ink); }
}