.page-features {
  --feat-side-w: 196px;
  --feat-swatch-1: var(--color-primary);
  --feat-swatch-2: color-mix(in srgb, var(--color-primary) 74%, var(--color-surface-deep));
  --feat-swatch-3: color-mix(in srgb, var(--color-primary) 44%, var(--color-surface-deep));
  --feat-swatch-4: color-mix(in srgb, var(--color-ink-soft) 48%, var(--color-surface-deep));
  --feat-swatch-5: color-mix(in srgb, var(--color-accent) 56%, var(--color-surface-deep));
  --feat-swatch-6: var(--color-accent);
  display: block;
}

/* ---------- 首屏数字带 ---------- */
.page-features .feat-hero {
  padding-block: var(--space-6) var(--space-8);
}

.page-features .feat-hero__crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent);
  margin-bottom: var(--space-6);
}

.page-features .feat-hero__crumb-link {
  color: var(--color-contrast-accent);
  text-decoration: none;
  border-bottom: var(--border-thin) dotted currentColor;
  padding-bottom: 1px;
}

.page-features .feat-hero__crumb-link:hover {
  color: var(--color-contrast-ink);
}

.page-features .feat-hero__grid {
  display: grid;
  gap: var(--space-6);
}

.page-features .feat-hero__eyebrow {
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-contrast-accent);
  margin: 0 0 var(--space-3);
}

.page-features .feat-hero__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 1.03;
  letter-spacing: 0.01em;
  color: var(--color-contrast-ink);
  max-width: 14ch;
}

.page-features .feat-hero__lede {
  margin: var(--space-4) 0 0;
  max-width: 58ch;
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent);
}

.page-features .feat-hero__metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-3);
  border-top: var(--border-thin) dashed var(--color-contrast-line);
  padding-top: var(--space-4);
}

.page-features .feat-hero__metric {
  display: flex;
  flex-direction: column;
  gap: 6px;
  border-left: 3px solid var(--color-contrast-accent);
  padding-left: var(--space-2);
}

.page-features .feat-hero__metric .metric__label {
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent);
}

.page-features .feat-hero__num {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  line-height: 1;
  letter-spacing: 0;
  color: var(--color-contrast-ink);
}

.page-features .feat-hero__metric .metric__unit {
  font-size: var(--text-xs);
  color: color-mix(in srgb, var(--color-contrast-ink) 58%, transparent);
}

/* ---------- 矩阵导览 ---------- */
.page-features .feat-lead {
  padding-block: var(--section-y);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-features .feat-lead__inner {
  display: grid;
  gap: var(--space-4);
}

.page-features .feat-lead__cap {
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-primary);
  margin: 0 0 var(--space-2);
}

.page-features .feat-lead__title {
  margin: 0 0 var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.page-features .feat-lead__desc {
  margin: 0;
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink-soft);
}

.page-features .feat-lead__fig {
  margin: 0;
}

.page-features .feat-lead__fig .figure__frame {
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  background: var(--color-surface-alt);
}

/* ---------- 主布局：左侧编号轨道 + 右侧矩阵 ---------- */
.page-features .feat-layout {
  display: grid;
  gap: var(--space-6);
  padding-block: var(--section-y-lg);
}

.page-features .feat-side {
  border-left: 2px solid var(--color-line);
  padding-left: var(--space-3);
}

.page-features .feat-side__cap {
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
  margin: 0 0 var(--space-2);
}

.page-features .feat-side__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-features .feat-side__link {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding: 6px var(--space-2);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  transition: background-color 160ms ease, color 160ms ease;
}

.page-features .feat-side__link:hover,
.page-features .feat-side__link.is-active {
  background: var(--color-primary-soft);
  color: var(--color-primary);
}

.page-features .feat-side__link .outline__num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-primary);
}

.page-features .feat-main {
  min-width: 0;
}

/* ---------- 章节编号牌 ---------- */
.page-features .feat-group + .feat-group {
  margin-top: var(--space-6);
}

.page-features .feat-group__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: start;
  gap: var(--space-2) var(--space-3);
  margin-bottom: var(--space-4);
}

.page-features .feat-group__num {
  grid-row: span 2;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 42px;
  height: 42px;
  background: var(--color-primary);
  color: var(--color-primary-ink);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: var(--text-base);
  letter-spacing: 0;
}

.page-features .feat-group__title {
  margin: 0;
  align-self: center;
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.page-features .feat-group__note {
  grid-column: 2;
  margin: 0;
  max-width: var(--measure);
  font-size: var(--text-sm);
  line-height: var(--leading-body);
  color: var(--color-ink-muted);
  border-left: 3px solid var(--color-highlight);
  padding-left: var(--space-2);
}

.page-features .feat-split {
  margin: var(--space-8) 0 var(--space-6);
  border: 0;
  border-top: var(--border-thin) dashed var(--color-line);
}

/* ---------- 错位矩阵 ---------- */
.page-features .feat-matrix {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-3);
}

.page-features .feat-mod {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-3);
  background: var(--color-surface);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
}

.page-features .feat-mod::before {
  content: "";
  position: absolute;
  left: -1px;
  top: var(--space-3);
  width: 3px;
  height: 24px;
  background: var(--color-primary);
  border-radius: var(--radius-sm);
  transform: scaleY(0.3);
  transform-origin: top center;
  transition: transform 160ms ease;
}

.page-features .feat-mod:hover::before {
  transform: scaleY(1);
}

.page-features .feat-mod__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0;
  color: var(--color-primary);
}

.page-features .feat-mod__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  color: var(--color-ink);
}

.page-features .feat-mod__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-1);
}

.page-features .feat-mod__list li {
  position: relative;
  padding-left: 14px;
  font-size: var(--text-sm);
  line-height: 1.66;
  color: var(--color-ink-soft);
}

.page-features .feat-mod__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 7px;
  height: 1px;
  background: var(--color-ink-muted);
}

.page-features .feat-mod--wide {
  background: var(--color-surface-alt);
}

.page-features .feat-matrix__fig {
  margin: 0;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-surface-alt);
}

.page-features .feat-matrix__fig .figure__frame {
  border: 0;
}

.page-features .feat-matrix__fig .figure__caption {
  padding: var(--space-2) var(--space-3);
  border-top: var(--border-thin) dotted var(--color-line);
  background: var(--color-surface);
}

/* ---------- 图例面板 ---------- */
.page-features .feat-legend {
  margin-bottom: var(--space-3);
}

.page-features .feat-legend--muted {
  background: var(--color-surface-alt);
}

.page-features .feat-legend__head {
  display: grid;
  gap: 4px;
}

.page-features .feat-legend__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.page-features .feat-legend__note {
  margin: 0;
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.page-features .feat-table-wrap {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-features .feat-table {
  width: 100%;
  min-width: 620px;
  border-collapse: collapse;
  font-size: var(--text-sm);
}

.page-features .feat-table__cap {
  caption-side: top;
  text-align: left;
  padding: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

.page-features .feat-table th,
.page-features .feat-table td {
  padding: var(--space-2) var(--space-3);
  text-align: left;
  vertical-align: top;
  border-bottom: var(--border-thin) solid var(--color-line);
  color: var(--color-ink-soft);
  line-height: 1.6;
}

.page-features .feat-table thead th {
  background: var(--color-surface-deep);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink);
  white-space: nowrap;
  font-weight: var(--weight-body);
}

.page-features .feat-table tbody tr:hover td {
  background: var(--color-primary-soft);
}

.page-features .feat-table td.idx {
  font-family: var(--font-mono);
  color: var(--color-primary);
  white-space: nowrap;
}

/* ---------- 色标与来源 ---------- */
.page-features .feat-swatch-panel .panel__body {
  display: grid;
  gap: var(--space-4);
}

.page-features .feat-swatch-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-2);
}

.page-features .feat-swatch {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.page-features .feat-swatch__chip {
  display: block;
  width: 26px;
  height: 12px;
  border-radius: var(--radius-sm);
  flex: none;
}

.page-features .feat-swatch__chip--1 { background: var(--feat-swatch-1); }
.page-features .feat-swatch__chip--2 { background: var(--feat-swatch-2); }
.page-features .feat-swatch__chip--3 { background: var(--feat-swatch-3); }
.page-features .feat-swatch__chip--4 { background: var(--feat-swatch-4); }
.page-features .feat-swatch__chip--5 { background: var(--feat-swatch-5); }
.page-features .feat-swatch__chip--6 { background: var(--feat-swatch-6); }

.page-features .feat-swatch__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-soft);
}

.page-features .feat-src-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-2);
  border-top: var(--border-thin) dashed var(--color-line);
  padding-top: var(--space-3);
}

.page-features .feat-src {
  display: grid;
  gap: 4px;
  align-items: start;
}

.page-features .feat-src__desc {
  font-size: var(--text-sm);
  line-height: 1.66;
  color: var(--color-ink-soft);
}

/* ---------- 检索路径 ---------- */
.page-features .feat-path {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: var(--border-thin) solid var(--color-line);
}

.page-features .feat-path__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px var(--space-3);
  padding: var(--space-3) var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-features .feat-path__bar {
  display: none;
}

.page-features .feat-path__name {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}

.page-features .feat-path__desc,
.page-features .feat-path__go {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.68;
  color: var(--color-ink-soft);
}

.page-features .feat-path__go {
  color: var(--color-ink-muted);
}

.page-features .feat-link {
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 42%, transparent);
  transition: border-color 160ms ease, color 160ms ease;
}

.page-features .feat-link:hover {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

/* ---------- 焦点可见性 ---------- */
.page-features a:focus-visible,
.page-features .feat-table:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-features .feat-hero__metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-features .feat-swatch-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-features .feat-src {
    grid-template-columns: 132px minmax(0, 1fr);
    align-items: center;
  }

  .page-features .feat-path__item {
    grid-template-columns: 68px minmax(0, 1fr);
    align-items: baseline;
  }

  .page-features .feat-path__bar {
    display: block;
    grid-column: 1 / -1;
    width: 100%;
    height: 0;
  }

  .page-features .feat-path__name {
    grid-column: 2;
  }

  .page-features .feat-path__desc,
  .page-features .feat-path__go {
    grid-column: 2;
  }
}

@media (min-width: 768px) {
  .page-features .feat-hero {
    padding-block: var(--space-8) var(--section-y-lg);
  }

  .page-features .feat-hero__grid {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-8);
  }

  .page-features .feat-lead__inner {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-6);
  }

  .page-features .feat-matrix {
    grid-template-columns: repeat(12, minmax(0, 1fr));
  }

  .page-features .feat-mod--4 { grid-column: span 6; }
  .page-features .feat-mod--5 { grid-column: span 6; }
  .page-features .feat-mod--6 { grid-column: span 6; }
  .page-features .feat-mod--7 { grid-column: span 6; }
  .page-features .feat-mod--8 { grid-column: span 12; }
  .page-features .feat-mod--12 { grid-column: span 12; }

  .page-features .feat-matrix__fig {
    grid-column: span 12;
  }

  .page-features .feat-mod__list--cols {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-1) var(--space-4);
  }
}

@media (min-width: 1024px) {
  .page-features .feat-hero__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    align-items: end;
    gap: var(--space-6);
  }

  .page-features .feat-hero__text {
    padding-right: var(--space-4);
  }

  .page-features .feat-lead__inner {
    grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
    align-items: start;
  }

  .page-features .feat-layout {
    grid-template-columns: var(--feat-side-w) minmax(0, 1fr);
    gap: var(--space-8);
    align-items: start;
  }

  .page-features .feat-side {
    position: sticky;
    top: var(--space-8);
  }

  .page-features .feat-mod--4 { grid-column: span 4; }
  .page-features .feat-mod--5 { grid-column: span 5; }
  .page-features .feat-mod--6 { grid-column: span 6; }
  .page-features .feat-mod--7 { grid-column: span 7; }
  .page-features .feat-mod--8 { grid-column: span 8; }

  .page-features .feat-matrix__fig {
    grid-column: span 12;
    margin-inline: 0;
  }

  .page-features .feat-swatch-panel .panel__body {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: start;
    gap: var(--space-6);
  }

  .page-features .feat-swatch-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-features .feat-src-list {
    border-top: 0;
    padding-top: 0;
    border-left: var(--border-thin) dashed var(--color-line);
    padding-left: var(--space-4);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-features .feat-mod::before,
  .page-features .feat-side__link,
  .page-features .feat-link {
    transition: none;
  }

  .page-features .feat-mod:hover::before {
    transform: scaleY(0.3);
  }
}