:root {
  --bg: #f7f9fc;
  --surface: #ffffff;
  --text: #1c2430;
  --muted: #5c6878;
  --border: #e1e6ee;
  --accent: #2563b8;
  --accent-strong: #1a4c93;

  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12161c;
    --surface: #1a2029;
    --text: #e9eef5;
    --muted: #9aa6b6;
    --border: #2a323e;
    --accent: #7ab4ff;
    --accent-strong: #a9cdff;
  }
}

* {
  box-sizing: border-box;
}

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

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, 'Segoe UI', 'Hiragino Sans', 'Yu Gothic UI', Meiryo, sans-serif;
  font-size: 17px;
  line-height: 1.7;
}

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

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

main,
.site-header,
.site-footer {
  width: 100%;
  max-width: 760px;
  margin: 0 auto;
  padding-left: 16px;
  padding-right: 16px;
}

.site-header {
  padding-top: 24px;
  padding-bottom: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 700;
  font-size: 19px;
  text-decoration: none;
}

.brand:hover {
  color: var(--text);
}

main {
  flex: 1;
  padding-top: 32px;
  padding-bottom: 48px;
}

h1 {
  margin: 0 0 8px;
  font-size: clamp(32px, 6vw, 44px);
  line-height: 1.2;
}

.lead {
  margin: 0 0 40px;
  color: var(--muted);
}

h2 {
  margin: 0 0 12px;
  font-size: 15px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

section + section {
  margin-top: 32px;
}

.site-footer {
  padding-top: 24px;
  padding-bottom: 32px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 14px;
}