/* ===== ページ全体のレイアウト ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px 20px;
  padding: 14px 28px;
  background: var(--surface);
  background: color-mix(in srgb, var(--surface) 82%, transparent);
  backdrop-filter: blur(12px) saturate(1.4);
  border-bottom: 1px solid var(--line);
}

.site-title {
  display: flex;
  align-items: center;
  gap: 14px;
}

.logo {
  display: grid;
  place-items: center;
  width: 46px; height: 46px;
  border-radius: 13px;
  background: var(--accent);
  background: linear-gradient(140deg, var(--accent), color-mix(in srgb, var(--accent) 55%, #22b8cf));
  color: var(--accent-ink);
  font-family: var(--mono);
  font-weight: 700;
  box-shadow: var(--shadow-md);
}

.site-title h1 {
  margin: 0;
  font-size: 1.15rem;
  letter-spacing: 0.02em;
}

.tagline {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  margin: 2px 0 0;
  font-size: 0.8rem;
  color: var(--ink-soft);
}

.count-badge {
  padding: 1px 9px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: var(--surface-2);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 1 1 280px;
  justify-content: flex-end;
}

.search-box { flex: 1 1 240px; max-width: 420px; }

.search-box input {
  width: 100%;
  padding: 10px 16px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: var(--surface-2);
  color: var(--ink);
  font: inherit;
  font-size: 0.88rem;
  transition: border-color 0.16s, box-shadow 0.16s, background 0.16s;
}
.search-box input:hover { border-color: var(--accent); }
.search-box input:focus {
  outline: none;
  background: var(--surface);
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59, 91, 219, 0.22);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 22%, transparent);
}

.theme-btn {
  flex: none;
  width: 40px; height: 40px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background: var(--surface-2);
  font-size: 1rem;
  line-height: 1;
  cursor: pointer;
  transition: transform 0.16s, border-color 0.16s;
}
.theme-btn:hover { transform: rotate(-18deg) scale(1.06); border-color: var(--accent); }

.shell {
  display: grid;
  grid-template-columns: 248px minmax(0, 1fr);
  align-items: start;
  gap: var(--gap);
  max-width: 1320px;
  margin: 0 auto;
  padding: var(--gap) 28px 64px;
}

/* --- サイドバー --- */
.sidebar {
  position: sticky;
  top: 94px;
  max-height: calc(100vh - 118px);
  overflow-y: auto;
  padding: 10px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  scrollbar-width: thin;
}

.nav-group + .nav-group {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
}

.nav-group-title {
  margin: 0;
  padding: 4px 10px 6px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
  text-transform: uppercase;
}

.nav-link {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  width: 100%;
  padding: 8px 10px 8px 14px;
  border: 0;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--ink);
  font: inherit;
  font-size: 0.87rem;
  text-align: left;
  cursor: pointer;
  transition: background 0.14s, color 0.14s;
}

/* 選択中を示す左の縦棒 */
.nav-link::before {
  content: "";
  position: absolute;
  left: 4px; top: 50%;
  width: 3px; height: 0;
  border-radius: 2px;
  background: var(--accent);
  transform: translateY(-50%);
  transition: height 0.18s ease;
}

.nav-link:hover { background: var(--surface-2); }
.nav-link[aria-current="true"] {
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 700;
}
.nav-link[aria-current="true"]::before { height: 60%; }

.nav-count {
  color: var(--ink-soft);
  font-size: 0.72rem;
  font-variant-numeric: tabular-nums;
}
.nav-link[aria-current="true"] .nav-count { color: var(--accent); }

/* --- 本文 --- */
.main { min-width: 0; }
.main:focus { outline: none; }

.section-head {
  margin-bottom: 20px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}
.section-head h2 {
  margin: 0 0 4px;
  font-size: 1.5rem;
  letter-spacing: 0.01em;
}
.section-head p { margin: 0; color: var(--ink-soft); font-size: 0.9rem; }

.entry-list { display: grid; gap: 18px; }

.empty {
  padding: 48px 40px;
  text-align: center;
  color: var(--ink-soft);
  background: var(--surface);
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius);
}

.site-footer {
  padding: 28px 28px 48px;
  text-align: center;
  color: var(--ink-soft);
  font-size: 0.8rem;
}
.site-footer code {
  padding: 1px 6px;
  border-radius: 5px;
  background: var(--surface-2);
}

@media (max-width: 880px) {
  .shell { grid-template-columns: 1fr; padding: 14px; }
  .site-header { padding: 12px 16px; }

  /* 縦の目次だと画面を占有してしまうので、横スクロールのタブにする */
  .sidebar {
    position: static;
    display: flex;
    gap: 8px;
    max-height: none;
    padding: 8px;
    overflow-x: auto;
    overflow-y: hidden;
    scroll-snap-type: x proximity;
  }
  .nav-group {
    display: flex;
    align-items: center;
    gap: 6px;
  }
  .nav-group + .nav-group {
    margin-top: 0;
    padding-top: 0;
    padding-left: 10px;
    border-top: 0;
    border-left: 1px solid var(--line);
  }
  .nav-group-title {
    padding: 0 2px;
    white-space: nowrap;
    font-size: 0.6rem;
  }
  .nav-link {
    width: auto;
    padding: 6px 12px;
    white-space: nowrap;
    scroll-snap-align: center;
  }
  .nav-link::before { display: none; }
}

@media (max-width: 560px) {
  .tagline-text { display: none; }
  .site-title h1 { font-size: 1.02rem; }
  .logo { width: 40px; height: 40px; border-radius: 11px; }
}