:root {
  --bg: #f5f5f7;
  --card: #ffffff;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --line: #e5e5ea;
  --blue: #0071e3;
  --radius: 18px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang HK", "PingFang TC",
    "SF Pro Text", "Helvetica Neue", sans-serif;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  max-width: 760px;
  margin: 0 auto;
  padding: 22px 20px 10px;
}

.brand {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text);
  text-decoration: none;
}

.site-header nav {
  display: flex;
  gap: 18px;
}

.site-header nav a {
  font-size: 15px;
  color: var(--muted);
  text-decoration: none;
}

.site-header nav a:hover { color: var(--text); }

.site-header nav a[aria-current="page"] {
  color: var(--text);
  font-weight: 600;
}

main {
  max-width: 760px;
  margin: 0 auto;
  padding: 10px 20px 40px;
}

h1 {
  font-size: 40px;
  line-height: 1.15;
  letter-spacing: -0.02em;
  font-weight: 700;
  margin: 24px 0 8px;
}

.meta {
  color: var(--muted);
  font-size: 15px;
  margin: 0 0 26px;
}

.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 26px 28px;
  margin-bottom: 16px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 8px 24px rgba(0, 0, 0, 0.03);
}

.card.highlight {
  background: linear-gradient(180deg, #ffffff 0%, #fbfbfd 100%);
  border: 1px solid var(--line);
}

h2 {
  font-size: 20px;
  letter-spacing: -0.01em;
  font-weight: 600;
  margin: 0 0 12px;
}

h3 {
  font-size: 17px;
  font-weight: 600;
  margin: 22px 0 6px;
}

h3:first-of-type { margin-top: 6px; }

p { margin: 0 0 12px; }

p:last-child { margin-bottom: 0; }

ul {
  margin: 0 0 12px;
  padding-left: 22px;
}

li { margin-bottom: 6px; }

a { color: var(--blue); }

.button {
  display: inline-block;
  margin: 6px 0 12px;
  padding: 12px 26px;
  border-radius: 980px;
  background: var(--blue);
  color: #fff;
  font-size: 16px;
  font-weight: 500;
  text-decoration: none;
}

.button:hover { background: #0077ed; }

.note {
  color: var(--muted);
  font-size: 15px;
}

.site-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
  max-width: 760px;
  margin: 0 auto;
  padding: 24px 20px 48px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}

.site-footer a {
  color: var(--muted);
  text-decoration: none;
}

.site-footer a:hover { color: var(--text); }

@media (max-width: 520px) {
  h1 { font-size: 32px; }
  .card { padding: 22px 20px; border-radius: 16px; }
  body { font-size: 16px; }
}