:root {
  --bg: #ffffff;
  --surface: #ffffff;
  --surface-soft: #f4f9fd;
  --text: #102a43;
  --muted: #4f6475;
  --primary: #0068b7;
  --primary-dark: #004b8d;
  --accent: #00a6d6;
  --border: #d8e8f2;
  --shadow: 0 14px 34px rgba(0, 75, 141, 0.12);
  --radius: 18px;
  --max-width: 1080px;
  --font-sans: "Noto Sans JP", -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.7;
  background: var(--bg);
}

a { color: inherit; }

.container {
  width: min(100% - 32px, var(--max-width));
  margin-inline: auto;
}

.skip-link {
  position: absolute;
  top: -48px;
  left: 16px;
  z-index: 10;
  padding: 10px 14px;
  color: #ffffff;
  background: var(--primary-dark);
  border-radius: 999px;
}

.skip-link:focus { top: 16px; }

.site-header {
  background: #ffffff;
  border-top: 8px solid var(--primary);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 18px 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--primary-dark);
  font-weight: 900;
  text-decoration: none;
  white-space: nowrap;
}

.brand-text {
  font-size: clamp(1rem, 2vw, 1.35rem);
  letter-spacing: -0.02em;
}

/* パンくず：現在位置を簡潔に示します。 */
.breadcrumb {
  padding: 14px 0 10px;
  font-size: 0.92rem;
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.breadcrumb li:not(:last-child)::after {
  margin-left: 6px;
  color: var(--muted);
  content: ">";
}

.breadcrumb a {
  color: var(--muted);
  text-decoration: none;
}

.breadcrumb [aria-current="page"] {
  color: var(--primary-dark);
  font-weight: 700;
}

/* ページ見出し：第2階層ページの主題を表示します。 */
.page-hero {
  background: #f7fbfe;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.page-hero-inner {
  padding: 30px 0 34px;
}

.page-hero h1 {
  margin: 0;
  color: var(--primary-dark);
  font-size: clamp(1.85rem, 4vw, 3rem);
  line-height: 1.25;
}

.lead {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 1.05rem;
}

h1,
h2 { margin: 0; line-height: 1.25; }

h1 {
  color: var(--primary-dark);
  font-size: clamp(1.8rem, 4vw, 3rem);
  letter-spacing: -0.03em;
}

.link-hero {
  padding: 30px 0 0;
}

.link-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.data-button {
  display: flex;
  align-items: center;
  min-height: 68px;
  padding: 18px 22px;
  color: var(--primary-dark);
  text-decoration: none;
  background: linear-gradient(180deg, #ffffff 0%, #eef8ff 100%);
  border: 2px solid #b7dbea;
  border-left: 8px solid var(--primary);
  border-radius: 16px;
  box-shadow: 0 10px 22px rgba(0, 75, 141, 0.1);
  transition: background-color 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.data-button:hover,
.data-button:focus-visible {
  background: #f4fbff;
  border-color: var(--primary);
  border-left-color: var(--primary-dark);
  box-shadow: 0 12px 26px rgba(0, 75, 141, 0.14);
}

.button-label {
  display: block;
  min-width: 0;
  color: var(--primary-dark);
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.45;
}

.content-section { padding: 24px 0 0; }

.panel {
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.panel h2 {
  color: var(--primary-dark);
  font-size: clamp(1.35rem, 2.5vw, 1.9rem);
}

.overview-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 18px 0 0;
}

.overview-list div {
  padding: 14px 16px;
  background: var(--surface-soft);
  border: 1px solid #e1eef6;
  border-radius: 14px;
}

.overview-list dt {
  color: var(--muted);
  font-size: 0.84rem;
  font-weight: 700;
}

.overview-list dd {
  margin: 4px 0 0;
  color: var(--text);
  font-size: 1.02rem;
  font-weight: 700;
}

.overview-list .wide-item {
  grid-column: 1 / -1;
}

.coordinate-pair {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.coordinate-pair span {
  display: block;
  padding: 10px 12px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 12px;
}

.coordinate-pair b {
  margin-right: 0.5em;
  color: var(--primary-dark);
}

.relation-image {
  margin: 18px 0 0;
  padding: 16px;
  text-align: center;
  background: #ffffff;
  border: 1px solid #e1eef6;
  border-radius: 16px;
}

.relation-image img {
  display: block;
  max-width: 100%;
  height: auto;
  margin-inline: auto;
}

a:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 4px;
  border-radius: 10px;
}

.brand:focus-visible,
.breadcrumb a:focus-visible,
.data-button:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

@media (min-width: 901px) {
  .site-header { border-top-width: 6px; }
  .header-inner { padding: 10px 0; }
  .brand-mark { width: 42px; }
  .breadcrumb { padding: 8px 0 6px; font-size: 0.86rem; }
  .page-hero-inner { padding: 20px 0 22px; }
  .lead { margin-top: 8px; font-size: 0.98rem; line-height: 1.55; }
  .link-hero { padding-top: 16px; }
  .link-grid { gap: 10px; }
  .data-button { min-height: 52px; padding: 12px 16px; border-radius: 13px; }
  .button-label { font-size: 0.95rem; }
  .content-section { padding-top: 16px; }
  .panel { padding: 18px; border-radius: 14px; }
  .panel h2 { font-size: clamp(1.18rem, 2vw, 1.5rem); }
  .overview-list { gap: 10px; margin-top: 12px; }
  .overview-list div { padding: 11px 12px; border-radius: 12px; }
  .relation-image { margin-top: 12px; padding: 12px; border-radius: 12px; }
}

html,
body {
  max-width: 100%;
  overflow-x: hidden;
}

img {
  max-width: 100%;
}

.header-inner,
.brand,
.brand-text,
.data-button,
.button-label,
.panel,
.overview-list div {
  min-width: 0;
}

.brand {
  width: 100%;
  white-space: normal;
}

.brand-mark {
  display: block;
  flex: 0 0 auto;
  width: 48px;
  height: auto;
  object-fit: contain;
}

.brand-text,
.button-label,
.overview-list dd {
  overflow-wrap: anywhere;
}

.relation-image {
  overflow: hidden;
}

@media (max-width: 900px) {
  .link-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .overview-list { grid-template-columns: 1fr; }
  .header-inner {
    justify-content: flex-start;
  }

  .brand-text {
    font-size: clamp(0.98rem, 3.2vw, 1.2rem);
    line-height: 1.4;
  }

  .page-hero h1 {
    font-size: clamp(1.65rem, 6vw, 2.3rem);
  }
}

@media (max-width: 560px) {
  body { font-size: 1.05rem; }
  .container { width: min(100% - 24px, var(--max-width)); }
  .brand-text { font-size: clamp(1.02rem, 4.2vw, 1.16rem); }
  .breadcrumb { font-size: 1rem; }
  .page-hero h1,
  h1 { font-size: clamp(1.75rem, 7vw, 2.25rem); }
  .lead { font-size: 1.05rem; }
  .link-hero { padding-top: 20px; }
  .link-grid { grid-template-columns: 1fr; gap: 10px; }
  .data-button { min-height: 58px; padding: 15px 16px; border-left-width: 6px; }
  .button-label { font-size: 1.05rem; }
  .panel { padding: 18px; }
  .panel h2 { font-size: 1.45rem; }
  .coordinate-pair { grid-template-columns: 1fr; }
  .overview-list dt { font-size: .95rem; }
  .overview-list dd { font-size: 1.05rem; }
  .header-inner {
    padding: 12px 0;
  }

  .brand {
    align-items: center;
    gap: 10px;
  }

  .brand-mark {
    width: 54px;
    height: auto;
  }

  .brand-text {
    flex: 1 1 auto;
    font-size: clamp(0.9rem, 4.2vw, 1.05rem);
    line-height: 1.4;
    letter-spacing: -0.03em;
  }

  .breadcrumb {
    padding: 10px 0 8px;
    font-size: 0.84rem;
  }

  .page-hero-inner {
    padding: 22px 0 24px;
  }

  .lead {
    margin-top: 12px;
    font-size: 0.96rem;
    line-height: 1.7;
  }

  .lead br {
    display: none;
  }

  .data-button {
    width: 100%;
  }

  .overview-list dd {
    font-size: 0.98rem;
  }

  .relation-image {
    margin-top: 14px;
    padding: 8px;
    border-radius: 10px;
  }
}

@media (max-width: 360px) {
  .container {
    width: min(100% - 20px, var(--max-width));
  }

  .brand-mark {
    width: 48px;
  }

  .brand-text {
    font-size: 0.86rem;
  }

  .panel {
    padding: 15px;
  }
}