.page-about {
  --ab-rail-width: 168px;
  --ab-gutter: clamp(28px, 4vw, 60px);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.78;
}

.page-about [hidden] {
  display: none !important;
}

.page-about .breadcrumb {
  padding: 22px 0 0;
}

.page-about .breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--stone);
}

.page-about .breadcrumb-list a {
  color: var(--dai);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.18s var(--ease), color 0.18s var(--ease);
}

.page-about .breadcrumb-list a:hover {
  color: var(--cinnabar);
  border-bottom-color: var(--cinnabar);
}

.page-about .breadcrumb-current {
  color: var(--ink);
  font-weight: 600;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  display: grid;
  gap: clamp(26px, 4vw, 48px);
  padding: clamp(26px, 4.5vw, 52px) 0 clamp(32px, 5vw, 60px);
}

.page-about .eyebrow {
  font-family: var(--mono);
  font-size: 12.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cinnabar);
  margin: 0 0 16px;
}

.page-about h1 {
  margin: 0 0 22px;
  font-family: var(--serif);
  font-weight: 900;
  font-size: clamp(32px, 7vw, 58px);
  line-height: 1.18;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .lede {
  margin: 0;
  font-size: clamp(16px, 1.6vw, 18px);
  line-height: 1.85;
  color: var(--dai);
}

.page-about .ab-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about .ab-hero-figure {
  margin: 0;
}

.page-about .figure-caption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--stone);
  border-left: var(--frame) solid var(--gold);
  padding-left: 12px;
}

/* ---------- 数据条 ---------- */
.page-about .ab-stat-strip {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--hair);
  border: var(--frame) solid var(--ink);
  box-shadow: var(--shadow-brut);
  margin-bottom: clamp(42px, 6vw, 76px);
}

.page-about .ab-stat {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px 16px 20px;
  background: var(--lotus);
}

.page-about .stat-num {
  font-family: var(--mono);
  font-weight: 700;
  font-size: clamp(24px, 3.6vw, 34px);
  line-height: 1;
  color: var(--cinnabar);
  letter-spacing: -0.01em;
}

.page-about .stat-label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--dai);
  letter-spacing: 0.02em;
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-chapter {
  display: grid;
  gap: 18px;
  padding: clamp(38px, 5.5vw, 80px) 0;
  border-top: 2px solid var(--ink);
}

.page-about .ab-rail {
  display: flex;
  align-items: center;
  gap: 12px;
}

.page-about .ab-rail-num {
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--paper);
  background: var(--cinnabar);
  padding: 3px 8px;
  line-height: 1.4;
}

.page-about .ab-rail-label {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--dai);
}

.page-about .ab-body {
  max-width: 78ch;
}

.page-about .section-title {
  margin: 0 0 18px;
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(25px, 4vw, 38px);
  line-height: 1.28;
  color: var(--dai);
}

.page-about .ab-body > p {
  margin: 0 0 18px;
  color: var(--ink);
}

/* ---------- 三条访问路径 ---------- */
.page-about .ab-path-list {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .ab-path {
  padding: 20px 20px 22px;
  background: var(--paper);
  border: var(--frame) solid var(--ink);
  box-shadow: 5px 5px 0 var(--gold);
  transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.page-about .ab-path:hover {
  transform: translate(-2px, -2px);
  box-shadow: 8px 8px 0 var(--cinnabar);
}

.page-about .ab-path-code {
  display: block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--stone);
  margin-bottom: 8px;
}

.page-about .ab-path h3 {
  margin: 0 0 8px;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 20px;
  color: var(--cinnabar);
}

.page-about .ab-path p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--ink);
}

/* ---------- 筛选按钮 ---------- */
.page-about .filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0 0 clamp(22px, 3vw, 34px);
}

.page-about .filter-btn {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  padding: 8px 15px;
  background: transparent;
  color: var(--dai);
  border: 2px solid var(--dai);
  cursor: pointer;
  transition: background 0.18s var(--ease), color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .filter-btn:hover {
  background: var(--gold-light);
  border-color: var(--gold);
  color: var(--ink);
}

.page-about .filter-btn[aria-pressed="true"] {
  background: var(--cinnabar);
  border-color: var(--cinnabar);
  color: var(--paper);
}

/* ---------- 主题档案 ---------- */
.page-about .ab-topic-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .ab-topic {
  display: grid;
  gap: 8px;
  padding: 20px 20px 24px;
  background: var(--paper);
  border: var(--frame) solid var(--ink);
  box-shadow: var(--shadow-brut);
  transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.page-about .ab-topic:hover {
  transform: translate(-2px, -2px);
  box-shadow: 8px 8px 0 var(--gold);
}

.page-about .ab-topic-code {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--proof);
}

.page-about .ab-topic h3 {
  margin: 0;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 20px;
  color: var(--dai);
}

.page-about .ab-topic p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--ink);
}

/* ---------- 发展历程 ---------- */
.page-about .ab-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 clamp(20px, 3vw, 34px);
  border-left: var(--frame) solid var(--gold);
}

.page-about .ab-stage {
  position: relative;
  padding-bottom: clamp(26px, 3.6vw, 42px);
}

.page-about .ab-stage:last-child {
  padding-bottom: 0;
}

.page-about .ab-stage::before {
  content: "";
  position: absolute;
  left: calc(-1 * clamp(20px, 3vw, 34px) - 8px);
  top: 8px;
  width: 11px;
  height: 11px;
  background: var(--cinnabar);
  border: 2px solid var(--ink);
  transform: rotate(45deg);
}

.page-about .ab-stage-tag {
  display: inline-block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--dai);
  background: var(--lotus);
  padding: 3px 10px;
  margin-bottom: 10px;
}

.page-about .ab-stage h3 {
  margin: 0 0 8px;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 20px;
  color: var(--ink);
}

.page-about .ab-stage p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--dai);
}

/* ---------- 团队 ---------- */
.page-about .ab-team-layout {
  display: grid;
  gap: clamp(24px, 3.5vw, 44px);
  margin-top: 30px;
}

.page-about .ab-team-figure {
  margin: 0;
}

.page-about .ab-role-list {
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
  border-top: 1px solid var(--hair);
}

.page-about .ab-role {
  display: grid;
  gap: 4px;
  padding: 16px 0;
  border-bottom: 1px solid var(--hair);
}

.page-about .ab-role dt {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--cinnabar);
}

.page-about .ab-role dd {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--ink);
}

.page-about .ab-team-note {
  margin: 22px 0 0;
  padding: 16px 18px;
  background: var(--lotus);
  border-left: var(--frame) solid var(--cinnabar);
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink);
}

/* ---------- 服务覆盖（深色章节） ---------- */
.page-about .ab-chapter--night {
  background: var(--night);
  border-top: 3px solid var(--gold);
  padding: clamp(32px, 5vw, 66px) clamp(20px, 3.4vw, 46px);
}

.page-about .ab-chapter--night .ab-rail-num {
  background: var(--gold);
  color: var(--night);
}

.page-about .ab-chapter--night .ab-rail-label {
  color: var(--gold-light);
}

.page-about .ab-chapter--night .section-title {
  color: var(--paper);
}

.page-about .ab-chapter--night .ab-body > p {
  color: var(--lotus);
}

.page-about .ab-chapter--night .figure-caption {
  color: var(--gold-light);
  border-left-color: var(--gold);
}

.page-about .ab-coverage-layout {
  display: grid;
  gap: clamp(24px, 3.5vw, 44px);
  margin-top: 26px;
}

.page-about .ab-coverage-figure {
  margin: 0;
}

.page-about .ab-support-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .ab-support-list li {
  position: relative;
  padding-left: 26px;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--lotus);
}

.page-about .ab-support-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 12px;
  height: 3px;
  background: var(--gold);
}

.page-about .ab-support-list strong {
  color: var(--paper);
  font-weight: 700;
}

/* ---------- 栏目导览 ---------- */
.page-about .ab-guide-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 0;
  border-top: 1px solid var(--hair);
}

.page-about .ab-guide-item {
  display: grid;
  gap: 8px;
  padding: 20px 0;
  border-bottom: 1px solid var(--hair);
  transition: background 0.18s var(--ease);
}

.page-about .ab-guide-item:hover {
  background: var(--lotus);
}

.page-about .ab-guide-code {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--stone);
}

.page-about .ab-guide-text h3 {
  margin: 0 0 6px;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 19px;
}

.page-about .ab-guide-text h3 a {
  color: var(--dai);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .ab-guide-text h3 a:hover {
  color: var(--cinnabar);
  border-bottom-color: var(--cinnabar);
}

.page-about .ab-guide-text p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--ink);
}

.page-about .ab-cta {
  margin-top: clamp(30px, 4vw, 48px);
  padding: clamp(22px, 3vw, 32px);
  border: var(--frame) solid var(--cinnabar);
  background: var(--lotus);
  display: grid;
  gap: 18px;
}

.page-about .ab-cta-text {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(17px, 2vw, 20px);
  line-height: 1.7;
  color: var(--ink);
}

.page-about .ab-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .ab-stat-strip {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .ab-path-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .ab-path:first-child {
    grid-column: 1 / -1;
  }

  .page-about .ab-topic-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .ab-team-layout,
  .page-about .ab-coverage-layout {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
    align-items: center;
  }

  .page-about .ab-chapter {
    grid-template-columns: var(--ab-rail-width) minmax(0, 1fr);
    gap: var(--ab-gutter);
  }

  .page-about .ab-rail {
    position: sticky;
    top: 96px;
    align-self: start;
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .page-about .ab-chapter--night .ab-rail {
    position: static;
  }

  .page-about .ab-guide-item {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 18px;
    align-items: start;
  }

  .page-about .ab-guide-code {
    padding-top: 4px;
  }
}

@media (min-width: 1100px) {
  .page-about .ab-topic-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-path,
  .page-about .ab-topic,
  .page-about .ab-guide-item,
  .page-about .filter-btn,
  .page-about .breadcrumb-list a,
  .page-about .ab-guide-text h3 a {
    transition: none;
  }

  .page-about .ab-path:hover,
  .page-about .ab-topic:hover {
    transform: none;
  }
}