:root {
  color-scheme: light;
  --ink: #18232d;
  --muted: #5b6874;
  --line: #d8dfe5;
  --soft: #f4f7f8;
  --white: #ffffff;
  --blue: #1769aa;
  --blue-dark: #0f4f82;
  --teal: #1f7564;
  --amber: #956315;
  --red: #9b3d3d;
  --max: 1120px;
  --reading: 720px;
  --radius: 6px;
}

* { box-sizing: border-box; }

html {
  background: var(--white);
  color: var(--ink);
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Noto Sans TC", "Microsoft JhengHei", "PingFang TC", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  letter-spacing: 0;
}

a { color: var(--blue); }
a:hover { color: var(--blue-dark); }
a:focus-visible,
[tabindex]:focus-visible {
  outline: 3px solid #82b9df;
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 10px;
  left: 10px;
  transform: translateY(-160%);
  padding: 8px 12px;
  border-radius: 4px;
  background: var(--ink);
  color: var(--white);
}

.skip-link:focus { transform: translateY(0); }

.site-container {
  width: min(var(--max), calc(100% - 40px));
  margin: 0 auto;
}

.reading-width { max-width: var(--reading); }

.site-header {
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.98);
}

.site-nav {
  min-height: 70px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.site-brand {
  color: var(--ink);
  font-size: 20px;
  font-weight: 800;
  text-decoration: none;
  white-space: nowrap;
}

.site-links {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 24px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-links a {
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
}

.site-links a:hover,
.site-links a[aria-current="page"] { color: var(--blue); }

.hero {
  padding: 88px 0 74px;
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1, h2, h3 {
  margin: 0;
  line-height: 1.25;
  letter-spacing: 0;
}

h1 { max-width: 940px; font-size: 52px; }
h2 { font-size: 32px; }
h3 { font-size: 18px; }

.hero-copy {
  max-width: 780px;
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 20px;
}

.hero-boundary {
  margin: 22px 0 0;
  font-weight: 800;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 9px 16px;
  border: 1px solid var(--blue);
  border-radius: 4px;
  color: var(--blue);
  font-weight: 800;
  text-decoration: none;
}

.button.primary { background: var(--blue); color: var(--white); }
.button.primary:hover { background: var(--blue-dark); color: var(--white); }
.button.secondary:hover { background: #edf5fa; }

.section {
  padding: 72px 0;
  border-bottom: 1px solid var(--line);
}

.section.soft { background: var(--soft); }
.section-heading { max-width: 760px; }
.section-intro { margin: 14px 0 0; color: var(--muted); font-size: 18px; }

.workflow {
  margin: 38px 0 0;
  padding: 0;
  counter-reset: workflow;
  list-style: none;
  border-top: 1px solid var(--line);
}

.workflow li {
  counter-increment: workflow;
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 20px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.workflow li::before {
  content: counter(workflow, decimal-leading-zero);
  color: var(--blue);
  font-weight: 800;
}

.workflow strong { display: block; }
.workflow span { display: block; margin-top: 3px; color: var(--muted); }

.metric-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 32px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--white);
}

.metric { padding: 24px; }
.metric + .metric { border-left: 1px solid var(--line); }
.metric strong { display: block; font-size: 34px; line-height: 1.1; }
.metric span { display: block; margin-top: 8px; color: var(--muted); }

.review-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: 32px;
}

.review-state {
  padding: 22px;
  border: 1px solid var(--line);
  border-top: 4px solid var(--teal);
  border-radius: var(--radius);
  background: var(--white);
}

.review-state.exclude { border-top-color: var(--red); }
.review-state.unsure { border-top-color: var(--amber); }
.review-state p { margin: 8px 0 0; color: var(--muted); }

.fact-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: 32px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.fact-list li { padding: 24px 0; }
.fact-list li + li { padding-left: 28px; border-left: 1px solid var(--line); }
.fact-list strong { display: block; font-size: 30px; }
.fact-list span { color: var(--muted); }

.split {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(280px, .9fr);
  gap: 64px;
  align-items: start;
}

.plain-list { margin: 22px 0 0; padding-left: 22px; }
.plain-list li + li { margin-top: 9px; }

.definition-list {
  margin: 28px 0 0;
  border-top: 1px solid var(--line);
}

.definition-row {
  display: grid;
  grid-template-columns: 180px minmax(0, 1fr);
  gap: 28px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.definition-row dt { font-weight: 800; }
.definition-row dd { margin: 0; color: var(--muted); }

.boundary-box {
  padding: 22px;
  border-left: 4px solid var(--blue);
  background: #edf5fa;
}

.boundary-box p { margin: 0; }
.boundary-box p + p { margin-top: 10px; }

.contact-status {
  display: inline-block;
  margin-top: 16px;
  padding: 8px 10px;
  border: 1px solid var(--line);
  border-radius: 4px;
  color: var(--muted);
  font-size: 14px;
}

.site-footer {
  padding: 46px 0 54px;
  background: #18232d;
  color: #dbe2e7;
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(180px, .7fr) minmax(280px, 1.3fr);
  gap: 50px;
}

.footer-brand { font-size: 20px; font-weight: 800; }
.footer-links { display: flex; flex-wrap: wrap; gap: 12px 22px; margin: 14px 0 0; }
.site-footer a { color: #dbe2e7; }
.footer-meta { margin: 0; color: #b6c0c8; }
.footer-meta + .footer-meta { margin-top: 4px; }
.copyright { margin: 24px 0 0; color: #93a0aa; font-size: 13px; }

.not-found {
  min-height: 58vh;
  display: grid;
  align-content: center;
  padding: 70px 0;
}

@media (max-width: 760px) {
  .site-container { width: min(100% - 28px, var(--max)); }
  .site-nav { align-items: flex-start; flex-direction: column; gap: 12px; padding: 16px 0; }
  .site-links { width: 100%; justify-content: flex-start; gap: 10px 18px; flex-wrap: wrap; }
  .hero { padding: 58px 0 52px; }
  h1 { font-size: 38px; }
  h2 { font-size: 28px; }
  .hero-copy { font-size: 18px; }
  .section { padding: 52px 0; }
  .metric-row, .review-grid, .fact-list, .split, .footer-grid { grid-template-columns: 1fr; }
  .metric + .metric { border-left: 0; border-top: 1px solid var(--line); }
  .fact-list li + li { padding-left: 0; border-left: 0; border-top: 1px solid var(--line); }
  .definition-row { grid-template-columns: 1fr; gap: 4px; }
  .actions { align-items: stretch; flex-direction: column; }
  .button { width: 100%; }
}