:root {
  color-scheme: light dark;
  --background: #f4f8f6;
  --surface: #ffffff;
  --text: #18322f;
  --muted: #5c706d;
  --border: #d8e5e1;
  --accent: #0f746a;
  --accent-soft: #d9f2eb;
  --shadow: 0 18px 50px rgb(20 62 56 / 10%);
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #071f23;
    --surface: #0b2a30;
    --text: #edf8f5;
    --muted: #afc7c2;
    --border: #24474a;
    --accent: #65d5c2;
    --accent-soft: #123f40;
    --shadow: 0 18px 50px rgb(0 0 0 / 24%);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", sans-serif;
  font-size: 17px;
  line-height: 1.75;
}

a { color: var(--accent); text-underline-offset: 0.2em; }

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  width: min(920px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1.25rem 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--text);
  font-size: 1.05rem;
  font-weight: 750;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 2.25rem;
  height: 2.25rem;
  place-items: center;
  border-radius: 0.75rem;
  background: var(--accent);
  color: var(--surface);
  font-weight: 800;
}

nav { display: flex; gap: 1rem; font-size: 0.94rem; }
nav [aria-current="page"] { color: var(--muted); font-weight: 700; }

main { width: min(920px, calc(100% - 2rem)); margin: 0 auto; }

article {
  padding: clamp(1.5rem, 4vw, 4rem);
  border: 1px solid var(--border);
  border-radius: 1.5rem;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.eyebrow {
  margin: 0 0 0.35rem;
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1 { margin: 0; font-size: clamp(2rem, 6vw, 3.4rem); line-height: 1.18; }
h2 { margin: 0 0 0.65rem; font-size: clamp(1.2rem, 3vw, 1.45rem); line-height: 1.35; }
p { margin: 0.7rem 0; }
ul { padding-left: 1.35rem; }
li + li { margin-top: 0.3rem; }
section { padding-top: 2rem; border-top: 1px solid var(--border); margin-top: 2rem; }

.effective-date { color: var(--muted); font-size: 0.95rem; }
.lead { max-width: 46rem; margin-top: 1.5rem; font-size: 1.12rem; }

code {
  border-radius: 0.35rem;
  background: var(--accent-soft);
  padding: 0.12rem 0.35rem;
  color: var(--text);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

footer {
  width: min(920px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1.5rem 0 3rem;
  color: var(--muted);
  text-align: center;
  font-size: 0.9rem;
}

@media (max-width: 560px) {
  body { font-size: 16px; }
  .site-header { align-items: flex-start; }
  nav { flex-direction: column; align-items: flex-end; gap: 0.3rem; }
  article { border-radius: 1rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}