.page-features {
  background: var(--color-surface);
}

/* 面包屑 */
.page-features .breadcrumb {
  padding-top: var(--space-2);
}
.page-features .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: var(--text-xs);
  font-family: var(--font-mono);
}
.page-features .crumb {
  color: var(--color-ink-muted);
  text-decoration: none;
}
.page-features a.crumb:hover,
.page-features a.crumb:focus-visible {
  color: var(--color-accent);
}
.page-features .crumb-sep {
  color: var(--color-line);
}

/* 首屏 */
.page-features .feat-hero {
  padding: var(--space-4) 0 var(--section-y);
}
.page-features .feat-hero__frame {
  position: relative;
  border: var(--border-thin) solid var(--color-line);
  background: var(--color-surface-alt);
  padding: var(--space-3) var(--space-2) var(--space-4);
  border-radius: var(--radius-sm);
}
.page-features .feat-hero__scale {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 6px;
  background-image: repeating-linear-gradient(90deg, var(--color-line) 0 1px, transparent 1px 14px);
}
.page-features .feat-hero__grid {
  display: grid;
  gap: var(--space-3);
}
.page-features .feat-hero__intro {
  padding-top: var(--space-2);
}
.page-features .feat-hero__title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  margin: var(--space-2) 0 var(--space-2);
}
.page-features .feat-hero__lead {
  max-width: 42ch;
  color: var(--color-ink-soft);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  margin: 0 0 var(--space-3);
}
.page-features .feat-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}
.page-features .feat-hero__media {
  margin: 0;
  align-self: start;
}
.page-features .feat-hero__media img,
.page-features .media-frame img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

/* 首屏数字带 */
.page-features .feat-hero__figures {
  display: grid;
  margin-top: var(--space-4);
  border-top: var(--border-thin) solid var(--color-line);
}
.page-features .feat-hero__figure {
  padding: var(--space-3) 0;
  border-bottom: var(--border-thin) solid var(--color-line);
}
.page-features .feat-figure__value {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  line-height: 1;
  color: var(--color-ink);
  letter-spacing: -0.01em;
}
.page-features .feat-figure__label {
  display: block;
  margin-top: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-primary);
}
.page-features .feat-figure__note {
  display: block;
  margin-top: 6px;
  font-size: var(--text-sm);
  line-height: 1.5;
  color: var(--color-ink-muted);
}
.page-features .feat-hero__rail {
  height: 3px;
  width: 42%;
  background: var(--color-accent);
  margin-top: var(--space-3);
}

/* 章节通用 */
.page-features .chapter {
  padding: var(--space-6) 0 var(--space-6);
  border-top: var(--border-thin) solid var(--color-line);
  scroll-margin-top: var(--space-8);
}
.page-features .chapter-head {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-2);
  align-items: start;
  margin-bottom: var(--space-4);
}
.page-features .chapter-num {
  font-family: var(--font-mono);
  font-size: var(--text-3xl);
  line-height: 1;
  color: var(--color-accent);
  letter-spacing: -0.02em;
}
.page-features .chapter-head__body {
  min-width: 0;
}
.page-features .chapter-title {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  line-height: var(--leading-heading);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
  margin: 0 0 var(--space-1);
}
.page-features .chapter-lead {
  max-width: var(--measure);
  margin: 0;
  color: var(--color-ink-soft);
  font-size: var(--text-base);
  line-height: var(--leading-body);
}

/* 索引 */
.page-features .filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin-bottom: var(--space-3);
}
.page-features .filter-btn {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  padding: 6px var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-ink-soft);
  cursor: pointer;
}
.page-features .filter-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}
.page-features .filter-btn[aria-pressed="true"] {
  border-color: var(--color-focus);
  color: var(--color-ink);
  background: var(--color-primary-soft);
}
.page-features .filter-btn:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

.page-features .feat-index {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: var(--border-thin) solid var(--color-line);
}
.page-features .feat-index__item {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: baseline;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-1);
  border-bottom: var(--border-thin) solid var(--color-line);
  text-decoration: none;
  color: var(--color-ink);
}
.page-features .feat-index__item:hover,
.page-features .feat-index__item:focus-visible {
  background: var(--color-surface-alt);
}
.page-features .feat-index__num {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-accent);
}
.page-features .feat-index__name {
  font-size: var(--text-base);
  color: var(--color-ink);
}
.page-features .feat-index__count {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
}

/* 指标网格 */
.page-features .feat-metrics {
  display: grid;
  gap: var(--space-2);
}
.page-features .kpi.feat-metric {
  position: relative;
  border: var(--border-thin) solid var(--color-line);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-sm);
  background: var(--color-surface-alt);
  padding: var(--space-3);
}
.page-features .kpi.feat-metric.kpi--accent {
  border-left-color: var(--color-accent);
  background: var(--color-highlight);
}
.page-features .kpi__num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-accent);
  margin: 0 0 var(--space-1);
  letter-spacing: 0.06em;
}
.page-features .kpi-value {
  font-family: var(--font-mono);
  font-size: var(--text-3xl);
  line-height: 1;
  color: var(--color-ink);
  margin: 0 0 var(--space-1);
}
.page-features .kpi-label {
  font-size: var(--text-sm);
  color: var(--color-primary);
  margin: 0 0 var(--space-2);
}
.page-features .kpi__caliber {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-ink-soft);
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-line);
}

/* 使用记录 / 平板专区 的分栏 */
.page-features .feat-records {
  display: grid;
  gap: var(--space-3);
}
.page-features .feat-records__media {
  margin: 0;
  border-radius: var(--radius-sm);
  overflow: hidden;
}

/* 深色折线区块 */
.page-features .feat-line-grid {
  display: grid;
  gap: var(--space-3);
  margin-top: var(--space-4);
}
.page-features .feat-line {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-radius: var(--radius-sm);
  padding: var(--space-3);
}
.page-features .feat-line__head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-2);
  margin-bottom: var(--space-2);
}
.page-features .feat-line__tag {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-contrast-accent);
}
.page-features .feat-line__axis {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-contrast-ink);
  opacity: 0.75;
}
.page-features .feat-line__svg {
  display: block;
  width: 100%;
  height: 180px;
}
.page-features .feat-line__grid line {
  stroke: var(--color-contrast-line);
  stroke-width: 1;
}
.page-features .feat-line__path {
  fill: none;
  stroke: var(--color-contrast-accent);
  stroke-width: 3;
  vector-effect: non-scaling-stroke;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 1400;
  stroke-dashoffset: 1400;
}
.page-features .feat-line.is-in .feat-line__path {
  animation: featLineDraw 1.5s ease-out forwards;
}
@keyframes featLineDraw {
  to { stroke-dashoffset: 0; }
}
.page-features .feat-line__legend {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  margin-top: var(--space-2);
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-contrast-line);
}
.page-features .feat-line__legend-item {
  font-size: var(--text-xs);
  line-height: 1.5;
  color: var(--color-contrast-ink);
  opacity: 0.8;
}
.page-features .feat-line__media {
  margin: 0;
  border-radius: var(--radius-sm);
  overflow: hidden;
}

/* 要点框 */
.page-features .callout {
  margin-top: var(--space-3);
  border-left: 4px solid var(--color-primary);
  background: var(--color-surface-alt);
  padding: var(--space-2) var(--space-3);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.page-features .callout--accent {
  border-left-color: var(--color-accent);
  background: var(--color-highlight);
}
.page-features .callout-title {
  margin: 0 0 var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}
.page-features .callout-body {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-soft);
}
.page-features .callout-extra {
  display: none;
  margin-top: var(--space-2);
  padding-top: var(--space-2);
  border-top: var(--border-thin) solid var(--color-line);
}
.page-features .callout-extra p {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink-soft);
}
.page-features .callout[data-expanded="true"] .callout-extra {
  display: block;
}
.page-features .callout-toggle {
  margin-top: var(--space-2);
  background: none;
  border: none;
  padding: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-accent);
  cursor: pointer;
  border-bottom: var(--border-thin) solid var(--color-accent);
}
.page-features .callout-toggle:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
}

/* 口径表 */
.page-features .split {
  display: grid;
  gap: var(--space-3);
}
.page-features .feat-table-wrap {
  overflow-x: auto;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}
.page-features .feat-table {
  width: 100%;
  min-width: 480px;
  border-collapse: collapse;
  font-size: var(--text-sm);
}
.page-features .feat-table__caption {
  caption-side: top;
  text-align: left;
  padding: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  border-bottom: var(--border-thin) solid var(--color-line);
  background: var(--color-surface-alt);
}
.page-features .feat-table th,
.page-features .feat-table td {
  text-align: left;
  padding: var(--space-2);
  border-bottom: var(--border-thin) solid var(--color-line);
  vertical-align: top;
}
.page-features .feat-table thead th {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  letter-spacing: 0.05em;
  background: var(--color-surface-deep);
}
.page-features .feat-table tbody th {
  font-weight: var(--weight-body);
  color: var(--color-ink);
}
.page-features .feat-table tbody td {
  font-family: var(--font-mono);
  color: var(--color-ink-soft);
}
.page-features .feat-table tbody tr:last-child th,
.page-features .feat-table tbody tr:last-child td {
  border-bottom: none;
}
.page-features .split__aside {
  display: grid;
  gap: var(--space-2);
  align-content: start;
}
.page-features .split__aside .callout {
  margin-top: 0;
}

/* 相邻栏目链接 */
.page-features .feat-links {
  display: grid;
  gap: 0;
  margin-top: var(--space-4);
  border-top: var(--border-thin) solid var(--color-line);
}
.page-features .feat-link {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-2);
  align-items: baseline;
  padding: var(--space-2) var(--space-1);
  border-bottom: var(--border-thin) solid var(--color-line);
  text-decoration: none;
  color: var(--color-ink);
}
.page-features .feat-link:hover,
.page-features .feat-link:focus-visible {
  background: var(--color-surface-alt);
}
.page-features .feat-link__num {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-accent);
}
.page-features .feat-link__body {
  display: grid;
  gap: 4px;
}
.page-features .feat-link__title {
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  color: var(--color-ink);
}
.page-features .feat-link__desc {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
  line-height: 1.5;
}

/* 动效 */
.page-features .reveal,
.page-features .reveal-frame {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 280ms ease-out, transform 280ms ease-out;
}
.page-features .reveal.is-in,
.page-features .reveal-frame.is-in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .page-features .reveal,
  .page-features .reveal-frame {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .page-features .feat-line__path {
    stroke-dashoffset: 0;
    animation: none;
  }
}

/* 平板及以上 */
@media (min-width: 720px) {
  .page-features .feat-hero__figures {
    grid-template-columns: repeat(3, 1fr);
  }
  .page-features .feat-hero__figure {
    padding: var(--space-3);
    border-bottom: none;
  }
  .page-features .feat-hero__figure + .feat-hero__figure {
    border-left: var(--border-thin) solid var(--color-line);
  }
  .page-features .feat-metrics {
    grid-template-columns: repeat(2, 1fr);
  }
  .page-features .feat-metrics--3 {
    grid-template-columns: repeat(3, 1fr);
  }
  .page-features .feat-records {
    grid-template-columns: 1.1fr 0.9fr;
    align-items: start;
  }
  .page-features .feat-records--reverse {
    grid-template-columns: 0.9fr 1.1fr;
  }
  .page-features .feat-records--reverse .feat-records__media {
    order: -1;
  }
}

/* 桌面 */
@media (min-width: 900px) {
  .page-features .feat-hero__frame {
    padding: var(--space-4) var(--space-4) var(--space-6);
  }
  .page-features .feat-hero__grid {
    grid-template-columns: 1.15fr 0.85fr;
    align-items: center;
    gap: var(--space-6);
  }
  .page-features .chapter {
    padding: var(--section-y) 0 var(--section-y);
  }
  .page-features .chapter-head {
    grid-template-columns: 96px 1fr;
    gap: var(--space-3);
  }
  .page-features .feat-index {
    grid-template-columns: repeat(2, 1fr);
  }
  .page-features .feat-index li:nth-child(odd) .feat-index__item {
    border-right: var(--border-thin) solid var(--color-line);
  }
  .page-features .feat-line-grid {
    grid-template-columns: 1.35fr 0.65fr;
    align-items: stretch;
  }
  .page-features .feat-line {
    padding: var(--space-4);
  }
  .page-features .split {
    grid-template-columns: 1fr 300px;
    gap: var(--space-4);
  }
  .page-features .feat-links {
    grid-template-columns: repeat(2, 1fr);
  }
  .page-features .feat-links .feat-link:nth-child(odd) {
    border-right: var(--border-thin) solid var(--color-line);
  }
}