:root {
  --site-sidebar-width: 300px;
}

.site-layout {
  display: grid;
  grid-template-columns: var(--site-sidebar-width) minmax(0, 1fr);
  align-items: start;
  width: 100%;
}

.site-content {
  min-width: 0;
}

.article-sidebar {
  position: sticky;
  top: 0;
  z-index: 20;
  width: 100%;
  height: 100vh;
  background: #f7f9fc;
  border-right: 1px solid var(--border, #e2e8f0);
  overflow-y: auto;
}

.article-sidebar-header {
  position: sticky;
  top: 0;
  z-index: 1;
  background: rgba(247,249,252,0.96);
  border-bottom: 1px solid var(--border, #e2e8f0);
  padding: 22px 20px 18px;
  backdrop-filter: blur(10px);
}

.article-sidebar-header h2 {
  font-family: var(--serif, Georgia, serif);
  font-size: 1.25rem;
  color: #273444;
  line-height: 1.15;
  margin: 0 0 6px;
}

.article-sidebar-header p {
  color: var(--muted, #64748b);
  font-size: 0.9rem;
  line-height: 1.45;
  margin: 0;
}

.article-sidebar-content {
  padding: 18px 16px 28px;
}

.article-group + .article-group {
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--border, #e2e8f0);
}

.article-group h3 {
  font-family: var(--sans, Helvetica, Arial, sans-serif);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #7d5b2f;
  margin: 0 0 10px;
}

.article-sidebar-list {
  list-style: none;
  display: grid;
  gap: 6px;
  margin: 0;
  padding: 0;
}

.article-sidebar-list a {
  display: block;
  padding: 9px 10px;
  border: 1px solid transparent;
  border-radius: 8px;
  color: #2f3b4a;
  line-height: 1.35;
  background: transparent;
  text-decoration: none;
}

.article-sidebar-list a:hover {
  text-decoration: none;
  border-color: #d7dee8;
  background: #ffffff;
}

.sidebar-link-title {
  display: block;
  font-weight: 800;
  font-size: 0.94rem;
}

.sidebar-link-note {
  display: block;
  color: var(--muted, #64748b);
  font-size: 0.82rem;
  line-height: 1.35;
  margin-top: 2px;
}

@media (max-width: 1080px) {
  .site-layout {
    grid-template-columns: 1fr;
  }

  .article-sidebar {
    position: relative;
    height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--border, #e2e8f0);
  }

  .article-sidebar-header {
    position: static;
  }

  .article-sidebar-content {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
  }

  .article-group + .article-group {
    margin-top: 0;
    padding-top: 0;
    border-top: 0;
  }
}

@media (max-width: 640px) {
  .article-sidebar-header {
    padding: 16px 16px 12px;
  }

  .article-sidebar-content {
    display: flex;
    gap: 12px;
    overflow-x: auto;
    padding: 14px 16px 18px;
    scroll-snap-type: x proximity;
  }

  .article-group {
    flex: 0 0 min(280px, calc(100vw - 48px));
    scroll-snap-align: start;
  }

  .article-sidebar-list a {
    background: #ffffff;
    border-color: #e5eaf1;
  }

  .sidebar-link-note {
    display: none;
  }
}