.about-hero {
  min-height: 0;
  margin-top: calc(-1 * var(--nav-h));
  padding-top: calc(3.5rem + var(--nav-h));
  padding-bottom: 2.5rem;
  text-align: center;
}

.about-hero .overline {
  justify-content: center;
  display: inline-flex;
  margin: 0 auto 1.25rem;
}

.about-hero h1 {
  font-size: clamp(2.25rem, 4.5vw, 3.25rem);
}

.fd-hero .lead {
  margin-bottom: 0;
}

.features-doc {
  max-width: 1180px;
  margin: 0 auto;
  padding: 1rem 1.5rem 4rem;
}

.fd-tools {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  margin-top: 2rem;
}

.fd-search {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  width: min(460px, 100%);
  padding: 0 1rem;
  height: 3rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--fg-muted);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.fd-search:focus-within {
  border-color: color-mix(in srgb, var(--accent) 55%, var(--border));
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 15%, transparent);
}

.fd-search input {
  flex: 1;
  min-width: 0;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--fg);
  font: inherit;
  font-size: 0.98rem;
}

.fd-open {
  height: 3rem;
  display: inline-flex;
  align-items: center;
}

.fd-layout {
  display: grid;
  grid-template-columns: 250px minmax(0, 1fr);
  gap: 2.5rem;
  align-items: start;
}

.fd-toc {
  position: sticky;
  top: 6rem;
  display: flex;
  flex-direction: column;
  gap: 2px;
  max-height: calc(100vh - 8rem);
  overflow-y: auto;
  padding: 0.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-elevated);
}

.fd-toc-group summary {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.6rem 0.7rem;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--fg);
  cursor: pointer;
  list-style: none;
  user-select: none;
  transition: background 0.15s ease;
}

.fd-toc-group summary::-webkit-details-marker {
  display: none;
}

.fd-toc-group summary:hover {
  background: var(--accent-soft);
}

.fd-toc-group-icon {
  display: grid;
  place-items: center;
  width: 1.75rem;
  height: 1.75rem;
  flex-shrink: 0;
  border-radius: 8px;
  color: var(--accent);
  background: var(--accent-soft);
}

.fd-toc-group summary > span:nth-child(2) {
  flex: 1;
  min-width: 0;
}

.fd-toc-chev {
  flex-shrink: 0;
  opacity: 0.55;
  transition: transform 0.2s ease;
}

.fd-toc-group[open] .fd-toc-chev {
  transform: rotate(180deg);
}

.fd-toc-links {
  display: flex;
  flex-direction: column;
  gap: 1px;
  margin: 0.15rem 0 0.4rem 1.55rem;
  padding-left: 0.6rem;
  border-left: 1px solid var(--border);
}

.fd-toc a {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.42rem 0.6rem;
  border-radius: var(--radius-sm);
  font-size: 0.86rem;
  color: var(--fg-muted);
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease, opacity 0.15s ease;
}

.fd-toc a svg {
  flex-shrink: 0;
}

.fd-toc a span:first-of-type {
  flex: 1;
  min-width: 0;
}

.fd-toc a:hover,
.fd-toc a.is-active {
  color: var(--accent);
  background: var(--accent-soft);
}

.fd-toc a.is-dim {
  opacity: 0.4;
}

.fd-toc-count {
  font-size: 0.75rem;
  font-variant-numeric: tabular-nums;
  opacity: 0.7;
}

.fd-group {
  margin-bottom: 1.5rem;
  scroll-margin-top: 6rem;
}

.fd-group[hidden] {
  display: none;
}

.fd-group-title {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin: 0 0 1.75rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
  font-size: clamp(1.7rem, 4vw, 2.3rem);
  letter-spacing: -0.03em;
}

.fd-group-icon {
  display: grid;
  place-items: center;
  width: 2.7rem;
  height: 2.7rem;
  flex-shrink: 0;
  border-radius: 12px;
  color: #fff;
  background: linear-gradient(135deg, var(--accent), color-mix(in srgb, var(--accent) 60%, #000));
}

.fd-group-count {
  margin-left: auto;
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-pill);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0;
  color: var(--accent);
  background: var(--accent-soft);
}

.fd-section {
  margin-bottom: 2.75rem;
  scroll-margin-top: 6rem;
}

.fd-section-title {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  margin: 0 0 1.1rem;
  font-size: clamp(1.2rem, 2.5vw, 1.45rem);
  letter-spacing: -0.02em;
}

.fd-section-icon,
.fd-card-icon {
  display: grid;
  place-items: center;
  flex-shrink: 0;
  border-radius: 10px;
  color: var(--accent);
  background: var(--accent-soft);
}

.fd-section-icon {
  width: 2.3rem;
  height: 2.3rem;
}

.fd-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.9rem;
}

.fd-card {
  display: flex;
  gap: 0.9rem;
  padding: 1.15rem 1.2rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.fd-card:hover {
  border-color: color-mix(in srgb, var(--accent) 35%, transparent);
  box-shadow: var(--shadow-sm);
}

.fd-card[hidden],
.fd-section[hidden] {
  display: none;
}

.fd-card-icon {
  width: 2.2rem;
  height: 2.2rem;
}

.fd-card-body {
  min-width: 0;
}

.fd-card h4 {
  margin: 0.15rem 0 0.35rem;
  font-size: 1rem;
  line-height: 1.35;
}

.fd-card p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.55;
  color: var(--fg-muted);
}

.fd-options {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-top: 0.7rem;
}

.fd-options span {
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-pill);
  font-size: 0.76rem;
  color: var(--fg);
  background: var(--bg);
  border: 1px solid var(--border);
}

.fd-section-desc {
  margin: -0.6rem 0 1.25rem;
  color: var(--fg-muted);
  line-height: 1.6;
}

.fd-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.1rem;
  margin-top: 0.75rem;
}

.fd-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.86rem;
  font-weight: 600;
  color: var(--accent);
  text-decoration: none;
}

.fd-links a:hover {
  text-decoration: underline;
}

.fd-empty {
  padding: 2.5rem 1rem;
  text-align: center;
  color: var(--fg-muted);
}

@media (max-width: 960px) {
  .fd-layout {
    grid-template-columns: minmax(0, 1fr);
    gap: 1.25rem;
  }

  .fd-toc {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.4rem;
    max-height: none;
    overflow: visible;
  }

  .fd-toc-group summary {
    justify-content: flex-start;
    border: 1px solid var(--border);
    background: var(--bg);
  }

  .fd-toc-links,
  .fd-toc-chev {
    display: none;
  }

  .fd-group-title {
    margin-bottom: 1.25rem;
  }
}

@media (max-width: 640px) {
  .features-doc {
    padding: 5.5rem 1rem 2rem;
  }

  .fd-hero {
    padding: 2rem 0 2rem;
  }

  .fd-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 0.6rem;
  }

  .fd-card {
    padding: 1rem;
  }
}