:root {
  color-scheme: light;
  --bg: #f7f8fa;
  --surface: #ffffff;
  --text: #182026;
  --muted: #5b6570;
  --line: #d9dee5;
  --accent: #156c86;
  --accent-soft: #e5f4f8;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans",
    "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  line-height: 1.75;
}

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

.page {
  width: min(920px, 100%);
  margin: 0 auto;
  padding: 24px 20px 56px;
}

.site-header {
  padding: 28px 0 20px;
  border-bottom: 1px solid var(--line);
}

.brand {
  margin: 0;
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
}

h1 {
  margin: 8px 0 0;
  font-size: clamp(28px, 5vw, 42px);
  line-height: 1.25;
}

h2 {
  margin: 36px 0 10px;
  font-size: 22px;
  line-height: 1.35;
}

h3 {
  margin: 24px 0 8px;
  font-size: 18px;
}

p,
li {
  font-size: 16px;
}

.lead {
  margin-top: 16px;
  color: var(--muted);
  font-size: 17px;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin-top: 16px;
  color: var(--muted);
  font-size: 14px;
}

.nav-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
  margin-top: 28px;
}

.nav-card {
  display: block;
  min-height: 124px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: inherit;
  text-decoration: none;
}

.nav-card strong {
  display: block;
  margin-bottom: 8px;
  font-size: 17px;
}

.nav-card span {
  color: var(--muted);
  font-size: 14px;
}

.content {
  margin-top: 28px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.notice {
  margin: 24px 0;
  padding: 16px;
  border-left: 4px solid var(--accent);
  background: var(--accent-soft);
}

.site-footer {
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 640px) {
  .page {
    padding: 18px 16px 40px;
  }

  .content {
    padding: 18px;
  }
}