/* 日本図鑑 — public site (GitHub Pages) */
:root {
  --bg: #f7f4ef;
  --bg-elevated: #f2eee7;
  --card: #ffffff;
  --navy: #38406a;
  --text: #2e3152;
  --text-secondary: #7c7a73;
  --text-tertiary: #a29f96;
  --border: #e6e1d6;
  --divider: #ece7dd;
  --accent: #f28c5b;
  --action: #1c1c1e;
  --max: 720px;
  --pad: clamp(20px, 4vw, 32px);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family:
    'Hiragino Sans',
    'Hiragino Kaku Gothic ProN',
    'Noto Sans JP',
    -apple-system,
    BlinkMacSystemFont,
    'Segoe UI',
    sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background:
    radial-gradient(1200px 480px at 12% -10%, rgba(56, 64, 106, 0.06), transparent 60%),
    radial-gradient(900px 420px at 100% 0%, rgba(242, 140, 91, 0.08), transparent 55%),
    var(--bg);
}

a {
  color: var(--navy);
  text-underline-offset: 3px;
}

a:hover {
  color: var(--text);
}

img {
  max-width: 100%;
  height: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(10px);
  background: rgba(247, 244, 239, 0.92);
  border-bottom: 1px solid var(--divider);
}

.site-header__inner,
.site-main,
.site-footer__inner {
  width: min(100% - (var(--pad) * 2), var(--max));
  margin-inline: auto;
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 64px;
}

.brand {
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--navy);
  text-decoration: none;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  font-size: 0.9375rem;
}

.nav a {
  color: var(--text-secondary);
  text-decoration: none;
}

.nav a:hover,
.nav a[aria-current='page'] {
  color: var(--navy);
}

.site-main {
  padding: 40px 0 72px;
}

.hero {
  padding: 28px 0 40px;
}

.hero__eyebrow {
  margin: 0 0 12px;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  text-transform: none;
  color: var(--text-tertiary);
}

.hero__title {
  margin: 0 0 12px;
  font-size: clamp(2.25rem, 6vw, 3.25rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: var(--navy);
}

.hero__catch {
  margin: 0 0 8px;
  font-size: clamp(1.25rem, 3vw, 1.625rem);
  font-weight: 500;
  color: var(--text);
}

.hero__sub {
  margin: 0 0 28px;
  font-size: 1.0625rem;
  color: var(--text-secondary);
}

.hero__lead {
  margin: 0 0 28px;
  max-width: 38rem;
  color: var(--text-secondary);
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 20px;
  border-radius: 12px;
  font-size: 0.9875rem;
  font-weight: 600;
  text-decoration: none;
  border: 1px solid transparent;
}

.button--primary {
  background: var(--action);
  color: #fff;
}

.button--primary:hover {
  color: #fff;
  opacity: 0.9;
}

.button--ghost {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}

.button[hidden],
.button.is-hidden {
  display: none !important;
}

.section {
  margin-top: 48px;
}

.section__title {
  margin: 0 0 16px;
  font-size: 1.375rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--navy);
}

.feature-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.feature-list li {
  padding: 16px 18px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  color: var(--text);
}

.page-title {
  margin: 0 0 8px;
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--navy);
}

.page-lead {
  margin: 0 0 32px;
  color: var(--text-secondary);
}

.faq {
  display: grid;
  gap: 16px;
}

.faq details {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 14px 18px;
}

.faq summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
}

.faq p {
  margin: 10px 0 4px;
  color: var(--text-secondary);
}

.prose h2 {
  margin: 36px 0 12px;
  font-size: 1.25rem;
  color: var(--navy);
}

.prose h3 {
  margin: 24px 0 8px;
  font-size: 1.0625rem;
  color: var(--text);
}

.prose p,
.prose li {
  color: var(--text-secondary);
}

.prose ul {
  padding-left: 1.25rem;
}

.note {
  margin-top: 24px;
  padding: 14px 16px;
  background: var(--bg-elevated);
  border-radius: 12px;
  color: var(--text-secondary);
  font-size: 0.9375rem;
}

.site-footer {
  border-top: 1px solid var(--divider);
  padding: 28px 0 40px;
  background: rgba(242, 238, 231, 0.55);
}

.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
  justify-content: space-between;
  align-items: center;
  font-size: 0.875rem;
  color: var(--text-tertiary);
}

.site-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 16px;
}

.site-footer a {
  color: var(--text-secondary);
  text-decoration: none;
}

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

@media (max-width: 560px) {
  .site-header__inner {
    align-items: flex-start;
    flex-direction: column;
    padding-block: 14px;
    min-height: 0;
  }

  .hero {
    padding-top: 12px;
  }
}