:root {
  --blue: #1a4fd6;
  --blue-dark: #0f338f;
  --yellow: #ffd400;
  --text: #1a1a1a;
  --muted: #5c6470;
  --bg: #f4f7ff;
  --card: #ffffff;
  --border: #d8e2ff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN",
    "Yu Gothic UI", "Yu Gothic", Meiryo, sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, var(--bg) 0%, #ffffff 240px);
  line-height: 1.75;
}

.site-header {
  background: var(--blue);
  color: #fff;
  padding: 2rem 1.25rem;
  text-align: center;
}

.site-header h1 {
  margin: 0;
  font-size: 1.5rem;
  letter-spacing: 0.08em;
}

.site-header p {
  margin: 0.5rem 0 0;
  color: var(--yellow);
  font-size: 0.875rem;
  font-weight: 700;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 3rem;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.5rem;
  box-shadow: 0 8px 24px rgba(26, 79, 214, 0.08);
}

.meta {
  color: var(--muted);
  font-size: 0.875rem;
  margin-bottom: 1.5rem;
}

h2 {
  font-size: 1.125rem;
  margin: 2rem 0 0.75rem;
  color: var(--blue-dark);
}

h2:first-of-type {
  margin-top: 0;
}

p,
li {
  font-size: 0.95rem;
}

ul,
ol {
  padding-left: 1.25rem;
}

nav.links {
  display: grid;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

nav.links a {
  display: block;
  padding: 1rem 1.25rem;
  border-radius: 12px;
  background: var(--blue);
  color: #fff;
  text-decoration: none;
  font-weight: 700;
  text-align: center;
}

nav.links a.secondary {
  background: #fff;
  color: var(--blue);
  border: 2px solid var(--blue);
}

.site-footer {
  text-align: center;
  color: var(--muted);
  font-size: 0.8125rem;
  margin-top: 2rem;
}

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

.back-link {
  display: inline-block;
  margin-bottom: 1rem;
  color: var(--blue);
  text-decoration: none;
  font-weight: 600;
}

.back-link:hover {
  text-decoration: underline;
}