:root {
  --bg: #f6f7fb;
  --card: #ffffff;
  --text: #1b1f2a;
  --muted: #5b6475;
  --line: #e2e6ef;
  --accent: #2448d6;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1420;
    --card: #151b29;
    --text: #e7eaf2;
    --muted: #9aa3b5;
    --line: #2a3348;
    --accent: #7c9bff;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans TC", "PingFang TC", sans-serif;
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 40px 16px 64px;
}

header { display: flex; align-items: center; gap: 14px; margin-bottom: 8px; }

.badge {
  width: 52px; height: 52px; border-radius: 15px;
  background: var(--accent); color: #fff;
  display: grid; place-items: center;
  font-weight: 900; font-size: 22px; flex: none;
}

h1 { font-size: 28px; line-height: 1.2; margin: 0; }
h2 { font-size: 20px; margin: 36px 0 8px; }
h3 { font-size: 16px; margin: 20px 0 4px; }
p, li { color: var(--text); }
.muted { color: var(--muted); }
a { color: var(--accent); }

nav { display: flex; flex-wrap: wrap; gap: 8px 18px; margin: 18px 0 8px; font-size: 15px; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 4px 20px 16px;
  margin-top: 20px;
}

.lang { margin-top: 48px; padding-top: 8px; border-top: 1px solid var(--line); }

footer { margin-top: 48px; font-size: 14px; color: var(--muted); }