:root {
  color-scheme: light;
  --bg: #ffffff;
  --card: #ffffff;
  --text: #111111;
  --subtle: #555555;
  --line: #dddddd;
  --brand: #111111;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", sans-serif;
  line-height: 1.7;
}

.container {
  width: min(920px, calc(100% - 32px));
  margin: 0 auto;
  padding: 24px 0 64px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 20px;
  margin-top: 16px;
}

h1,
h2,
h3 {
  line-height: 1.3;
  margin: 0 0 12px;
}

h1 {
  font-size: clamp(1.6rem, 3vw, 2.1rem);
}

h2 {
  margin-top: 28px;
  font-size: clamp(1.15rem, 2.2vw, 1.35rem);
}

p,
li {
  margin: 0 0 10px;
}

ul {
  margin: 8px 0 12px 20px;
  padding: 0;
}

a {
  color: var(--brand);
  text-decoration: underline;
}

a:hover {
  opacity: 0.85;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  margin: 12px 0 8px;
}

nav a {
  font-weight: 600;
}

.muted {
  color: var(--subtle);
}

.footer {
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  color: var(--subtle);
  font-size: 0.95rem;
}