:root {
  color-scheme: light;
  --ink: #132026;
  --muted: #5d6b72;
  --line: #d9e1e4;
  --paper: #ffffff;
  --soft: #eef7f8;
  --accent: #0ea5b7;
  --accent-dark: #087585;
  --warm: #fff7e8;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #f7fafb;
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP", "Segoe UI", sans-serif;
  line-height: 1.75;
}

a {
  color: var(--accent-dark);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.2em;
}

.site-header {
  background: linear-gradient(135deg, #e8fafb 0%, #fff8ec 100%);
  border-bottom: 1px solid var(--line);
}

.header-inner,
.content,
.site-footer {
  width: min(960px, calc(100% - 32px));
  margin: 0 auto;
}

.header-inner {
  padding: 44px 0 36px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
}

h1 {
  max-width: 760px;
  margin: 20px 0 10px;
  font-size: clamp(32px, 6vw, 56px);
  line-height: 1.15;
  letter-spacing: 0;
}

.lead {
  max-width: 720px;
  margin: 0;
  color: var(--muted);
  font-size: 18px;
}

.content {
  padding: 34px 0 56px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.card,
.doc-section {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.card {
  display: block;
  padding: 22px;
  color: inherit;
  text-decoration: none;
}

.card:hover {
  border-color: var(--accent);
}

.card h2,
.doc-section h2 {
  margin: 0 0 10px;
  font-size: 22px;
  line-height: 1.3;
}

.card p {
  margin: 0;
  color: var(--muted);
}

.doc-section {
  margin: 16px 0;
  padding: 24px;
}

.doc-section h3 {
  margin: 20px 0 8px;
  font-size: 17px;
}

.doc-section p,
.doc-section ul,
.doc-section ol {
  margin-top: 0;
}

.doc-section li + li {
  margin-top: 6px;
}

.notice {
  padding: 16px 18px;
  border: 1px solid #f2d49b;
  border-radius: 8px;
  background: var(--warm);
  color: #5f4313;
}

.meta {
  color: var(--muted);
  font-size: 14px;
}

.site-footer {
  padding: 28px 0 40px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 18px;
  margin-bottom: 8px;
}

@media (max-width: 640px) {
  .header-inner {
    padding: 32px 0 28px;
  }

  .content {
    padding-top: 24px;
  }

  .doc-section {
    padding: 20px;
  }
}