:root {
  --font-body: "Trebuchet MS", "Segoe UI", Arial, sans-serif;
  --font-heading: Georgia, "Times New Roman", serif;
  --site-width: 1180px;
  --radius: 18px;
  --shadow-soft: 0 20px 44px rgba(0, 0, 0, 0.12);
  --shadow-card: 0 10px 24px rgba(0, 0, 0, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  line-height: 1.65;
  background: var(--page-bg);
  color: var(--text-color);
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
}

.site-shell {
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(255, 255, 255, 0.76), transparent 28%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.32), transparent 22rem);
}

.container {
  width: min(calc(100% - 2rem), var(--site-width));
  margin: 0 auto;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--nav-bg);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  backdrop-filter: blur(12px);
}

.topbar-inner {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  gap: 1rem;
  padding: 0.9rem 0;
}

.brand {
  text-decoration: none;
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 700;
  color: #f4efdf;
}

.topnav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  width: 100%;
}

.nav-link {
  text-decoration: none;
  padding: 0.58rem 0.95rem;
  border-radius: 999px;
  color: var(--nav-link);
  font-weight: 700;
  font-size: 0.95rem;
}

.nav-link:hover,
.nav-link:focus-visible,
.nav-link.is-active {
  background: var(--nav-link-active-bg);
  color: var(--nav-link-active);
}

.hero {
  padding: 2.5rem 0 3.5rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 1.5rem;
  align-items: center;
}

.hero-copy,
.hero-visual,
.feature-card,
.section-card,
.content-panel,
.side-panel,
.topic-card,
.timeline-card,
.notice-card {
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
  background: var(--surface-bg);
  box-shadow: var(--shadow-card);
}

.hero-copy {
  padding: 2rem;
  box-shadow: var(--shadow-soft);
}

.hero-visual {
  overflow: hidden;
  position: relative;
  box-shadow: var(--shadow-soft);
}

.hero-visual img {
  width: 100%;
  height: 100%;
  min-height: 27rem;
  object-fit: cover;
}

.hero-note {
  position: absolute;
  left: 1rem;
  right: 1rem;
  bottom: 1rem;
  padding: 1rem;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.9);
  color: #17212f;
}

.eyebrow {
  display: inline-block;
  margin-bottom: 0.8rem;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

h1,
h2,
h3 {
  margin: 0 0 1rem;
  font-family: var(--font-heading);
  line-height: 1.15;
  color: var(--heading-color);
}

h1 {
  font-size: clamp(2.2rem, 5vw, 4.2rem);
}

h2 {
  font-size: clamp(1.6rem, 4vw, 2.3rem);
}

h3 {
  font-size: 1.18rem;
}

p {
  margin: 0 0 1rem;
}

.muted {
  color: var(--muted-color);
}

.hero-actions,
.button-row,
.link-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.9rem;
  padding: 0.8rem 1.15rem;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 700;
}

.button-primary {
  background: var(--accent);
  color: #fff8f1;
}

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

.section {
  padding-bottom: 3.5rem;
}

.feature-grid,
.category-grid,
.topic-grid,
.timeline-grid,
.notice-grid {
  display: grid;
  gap: 1.25rem;
}

.feature-grid,
.category-grid,
.notice-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.topic-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.timeline-grid {
  grid-template-columns: 1fr;
}

.feature-card,
.topic-card,
.timeline-card,
.notice-card {
  padding: 1.4rem;
}

.embed-frame {
  width: 100%;
  min-height: 88vh;
  border: 0;
  border-radius: 12px;
  background: #ffffff;
}

.category-grid .feature-card img,
.topic-card img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  border-radius: 12px;
  margin-bottom: 1rem;
}

.page-header {
  padding: 2.4rem 0 1.6rem;
}

.page-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 1.25rem;
  padding-bottom: 3.5rem;
}

.content-panel {
  padding: 2rem;
}

.side-panel {
  padding: 1.25rem;
  position: sticky;
  top: 5.4rem;
  align-self: start;
}

.side-panel h2 {
  font-size: 1.35rem;
}

.side-menu {
  display: grid;
  gap: 0.55rem;
}

.side-menu a {
  text-decoration: none;
  padding: 0.75rem 0.9rem;
  border-radius: 12px;
  background: var(--sidebar-bg);
}

.side-menu a:hover,
.side-menu a:focus-visible {
  background: var(--sidebar-hover);
  color: var(--sidebar-hover-text);
}

.highlight-box {
  margin: 1.5rem 0;
  padding: 1.25rem;
  border-radius: 16px;
  background: var(--highlight-bg);
  color: var(--highlight-text);
}

.highlight-box .link-list a {
  color: var(--highlight-link);
}

.highlight-box .link-list a:hover {
  background: #E0D3A6;
  color: #fff;
}

.highlight-box .link-list a:focus-visible {
  color: var(--highlight-link);
}

.link-list {
  margin-top: 0.8rem;
}

.link-list a {
  text-decoration: none;
  padding: 0.55rem 0.8rem;
  border-radius: 999px;
  background: var(--surface-muted);
  font-weight: 700;
}

.link-list a:hover,
.link-list a:focus-visible {
  background: var(--accent);
  color: #fff8f1;
}

.timeline-card {
  border-left: 4px solid var(--accent);
}

.footer {
  border-top: 1px solid var(--border-color);
  background: var(--footer-bg);
}

.footer-inner {
  padding: 1.25rem 0 2rem;
  color: var(--muted-color);
}

.scroll-top-button {
  position: fixed;
  right: 1rem;
  bottom: 1rem;
  z-index: 30;
  display: none;
  align-items: center;
  justify-content: center;
  width: 4.75rem;
  height: 4.75rem;
  border-radius: 999px;
  background: var(--highlight-bg);
  color: var(--highlight-text);
  text-decoration: none;
  font-size: 2rem;
  font-weight: 700;
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(255, 255, 255, 0.18);
  opacity: 0;
  pointer-events: none;
  transform: translateY(0.5rem);
  transition: opacity 0.2s ease, transform 0.2s ease, background 0.2s ease, color 0.2s ease;
}

.scroll-top-button:hover,
.scroll-top-button:focus-visible {
  background: var(--accent);
  color: #171f29;
}

.scroll-top-button.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

@media (max-width: 1024px) {
  .hero-grid,
  .page-wrap,
  .feature-grid,
  .category-grid,
  .topic-grid,
  .notice-grid {
    grid-template-columns: 1fr;
  }

  .side-panel {
    position: static;
  }
}

@media (max-width: 720px) {
  .topbar-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .hero-copy,
  .content-panel,
  .feature-card,
  .topic-card,
  .timeline-card,
  .notice-card,
  .side-panel {
    padding: 1.25rem;
  }

  .hero-actions,
  .button-row {
    flex-direction: column;
  }

  .button {
    width: 100%;
  }

  .scroll-top-button {
    display: inline-flex;
  }
}

.topbar {
  position: sticky;
  top: 0;
}

@media (max-width: 1024px) {
  .topbar {
    position: static;
  }
}