/* ---------------- header ---------------- */
.header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 10px 20px;
  display: flex;
  align-items: center;
  gap: 16px;
}
.brand {
  display: flex;
  align-items: baseline;
  gap: 8px;
  letter-spacing: -0.01em;
}
.brand-mark {
  font-weight: 600;
  font-size: 13.5px;
  color: var(--text);
}
.brand-sub {
  color: var(--text-faint);
  font-size: 11.5px;
}
.search-wrap {
  flex: 1;
  display: flex;
  justify-content: center;
}
.search {
  width: 100%;
  max-width: 380px;
  position: relative;
}
.search input {
  width: 100%;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 6px 10px 6px 28px;
  outline: none;
  transition: border-color 120ms ease, background 120ms ease;
}
.search input::placeholder { color: var(--text-faint); }
.search input:focus { border-color: var(--border-strong); }
.search svg {
  position: absolute;
  left: 9px;
  top: 50%;
  transform: translateY(-50%);
  width: 12px;
  height: 12px;
  color: var(--text-faint);
}
.kbd {
  position: absolute;
  right: 7px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 10px;
  color: var(--text-faint);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 0 4px;
  pointer-events: none;
}
.theme-toggle {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 4px 7px;
  color: var(--text-dim);
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 12px;
  transition: border-color 120ms ease, color 120ms ease;
}
.theme-toggle:hover { border-color: var(--border-strong); color: var(--text); }
.theme-toggle svg { width: 12px; height: 12px; }

/* ---------------- top section nav ---------------- */
.section-nav-wrap {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
}
.section-nav {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  gap: 4px;
  overflow-x: auto;
}
.section-nav a {
  padding: 8px 12px;
  color: var(--text-faint);
  font-size: 12.5px;
  border-bottom: 1px solid transparent;
  margin-bottom: -1px;
  white-space: nowrap;
  transition: color 120ms ease, border-color 120ms ease;
}
.section-nav a:hover { color: var(--text-dim); }
.section-nav a.active {
  color: var(--text);
  border-bottom-color: var(--text);
}

/* ---------------- shell ---------------- */
.shell {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 24px 20px 64px;
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 28px;
  align-items: start;
}

.intro {
  grid-column: 1 / -1;
  margin-bottom: 4px;
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
}
.intro h1 {
  font-size: 20px;
  line-height: 1.1;
  letter-spacing: -0.015em;
  margin: 0;
  font-weight: 600;
}
.intro p {
  color: var(--text-dim);
  margin: 0;
  font-size: 12.5px;
}

/* ---------------- footer ---------------- */
.site-foot {
  border-top: 1px solid var(--border);
  margin-top: 40px;
}
.foot-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 18px 20px 28px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 6px 24px;
  color: var(--text-faint);
  font-size: 11.5px;
  line-height: 1.5;
}

/* ---------------- responsive ---------------- */
@media (max-width: 860px) {
  .shell {
    grid-template-columns: 1fr;
    padding: 24px 16px 60px;
  }
  .sidebar {
    position: static;
    flex-direction: row;
    flex-wrap: wrap;
    gap: 20px;
    padding-bottom: 4px;
    border-bottom: 1px solid var(--border);
  }
  .filter-group { min-width: 160px; flex: 1; }
  .chip-list { flex-direction: row; flex-wrap: wrap; }
  .chip { padding: 5px 9px; }
  .chip .count { display: none; }
  .header-inner { padding: 12px 16px; gap: 12px; }
  .brand-sub { display: none; }
  .intro h1 { font-size: 18px; }
  .detail-shell { padding: 16px 16px 60px; }
  .detail-head h2 { font-size: 20px; }
}
@media (max-width: 560px) {
  .search { max-width: none; }
  .kbd { display: none; }
  .grid { grid-template-columns: 1fr; }
}