:root {
  color-scheme: light dark;
  --bg: #f6f7f9;
  --card: #ffffff;
  --text: #1a1d21;
  --muted: #5c6570;
  --accent: #4f46e5;
  --border: #e4e7ec;
  --code: #eef0f4;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111318;
    --card: #1a1f27;
    --text: #f3f4f6;
    --muted: #a8b0bb;
    --accent: #818cf8;
    --border: #2a3140;
    --code: #252b36;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Hiragino Sans",
    "Noto Sans JP", sans-serif;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}

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

header,
main,
footer {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

header {
  padding-top: 2.5rem;
  padding-bottom: 1rem;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
}

.site-nav a {
  text-decoration: none;
}

.site-nav a[aria-current="page"] {
  font-weight: 600;
  text-decoration: underline;
}

h1 {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  line-height: 1.2;
  margin: 0 0 0.5rem;
}

.lead {
  color: var(--muted);
  font-size: 1.05rem;
  margin: 0 0 1.5rem;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem 1.5rem;
  margin-bottom: 1rem;
}

.card h2 {
  margin-top: 0;
  font-size: 1.15rem;
}

ul {
  padding-left: 1.25rem;
}

li + li {
  margin-top: 0.35rem;
}

.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1rem 0 1.5rem;
}

.badge {
  display: inline-block;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  background: var(--code);
  font-size: 0.85rem;
  color: var(--muted);
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 1.5rem 0;
}

.button {
  display: inline-block;
  padding: 0.65rem 1rem;
  border-radius: 10px;
  background: var(--accent);
  color: #fff !important;
  text-decoration: none;
  font-weight: 600;
}

.button.secondary {
  background: transparent;
  color: var(--accent) !important;
  border: 1px solid var(--border);
}

footer {
  padding: 2rem 1.25rem 3rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.lang-block + .lang-block {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}

.lang-label {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.75rem;
}