.page-about {
  --about-rail-w: 190px;
  --about-section-gap: clamp(52px, 7.5vw, 108px);
  --about-radius: 0;
  display: block;
  background-color: var(--sandstone);
  color: var(--space);
  padding-bottom: clamp(48px, 7vw, 96px);
}

.page-about .breadcrumbs {
  padding-top: clamp(18px, 3vw, 32px);
}

.page-about .about-intro {
  padding: clamp(28px, 5vw, 60px) 0 clamp(30px, 5vw, 64px);
  border-bottom: var(--edge);
}

.page-about .about-intro .display-title {
  margin: 14px 0 0;
  max-width: 18ch;
}

.page-about .about-lede {
  margin: clamp(20px, 3vw, 30px) 0 0;
  max-width: 66ch;
  font-size: var(--fs-18);
  line-height: 1.85;
  color: var(--space);
}

.page-about .about-stats {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(18px, 4vw, 52px);
  margin: clamp(28px, 4vw, 46px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .stat-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 92px;
}

.page-about .stat-item + .stat-item {
  padding-left: clamp(18px, 4vw, 52px);
  border-left: 1px solid var(--sandstone-deep);
}

.page-about .stat-num {
  font-size: clamp(2rem, 4vw, var(--fs-34));
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--danxia);
  font-variant-numeric: tabular-nums;
}

.page-about .stat-label {
  font-size: var(--fs-13);
  letter-spacing: 0.06em;
  color: var(--space-lift);
}

/* ---------- 主体骨架 ---------- */

.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 56px);
  padding-top: clamp(28px, 4.5vw, 60px);
}

.page-about .about-rail {
  padding: 0 0 4px;
}

.page-about .rail-head {
  display: none;
  margin: 0 0 14px;
  font-size: var(--fs-12);
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--sandstone-deep);
}

.page-about .rail-list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.page-about .rail-list::-webkit-scrollbar {
  display: none;
}

.page-about .rail-link {
  display: block;
  white-space: nowrap;
  padding: 8px 14px;
  border: var(--edge);
  border-radius: var(--about-radius);
  font-size: var(--fs-13);
  letter-spacing: 0.08em;
  text-decoration: none;
  color: var(--space);
  background-color: transparent;
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  border-color: var(--danxia);
  color: var(--danxia);
}

.page-about .rail-link.is-active {
  color: var(--danxia);
}

.page-about .about-flow {
  min-width: 0;
}

/* ---------- 章节通用 ---------- */

.page-about .about-section + .about-section {
  margin-top: var(--about-section-gap);
}

.page-about .section-head {
  margin-bottom: clamp(20px, 3vw, 34px);
}

.page-about .section-head .eyebrow {
  color: var(--danxia);
  margin: 0 0 10px;
}

.page-about .section-head .section-title {
  margin: 0;
  max-width: 22ch;
}

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

.page-about .about-figure--wide {
  margin-bottom: clamp(24px, 4vw, 44px);
}

.page-about .about-figure figcaption {
  margin-top: 12px;
  font-size: var(--fs-13);
  line-height: 1.6;
  color: var(--space-lift);
  padding-left: 12px;
  border-left: 2px solid var(--sand);
}

.page-about .about-figure .media-frame {
  border: var(--edge);
  box-shadow: var(--shadow-paper);
  background-color: var(--space);
}

.page-about .about-figure .media-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about-figure .media-frame__strip {
  display: block;
  height: 6px;
  background: linear-gradient(90deg, var(--danxia) 0%, var(--danxia) 42%, var(--sand) 42%, var(--sand) 74%, var(--cyan) 74%, var(--cyan) 100%);
}

.page-about .about-figure .media-frame__badge {
  position: absolute;
  left: 0;
  bottom: 0;
  padding: 7px 14px;
  background-color: var(--danxia);
  color: #fff;
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

/* ---------- 内容定位 ---------- */

.page-about .who-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
}

.page-about .who-text p {
  margin: 0 0 1.05em;
  font-size: var(--fs-18);
  line-height: 1.85;
}

.page-about .who-text p:last-child {
  margin-bottom: 0;
}

/* ---------- 发展阶段 ---------- */

.page-about .stage-list {
  display: grid;
  gap: 0;
  border-top: var(--edge);
}

.page-about .stage {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  padding: clamp(22px, 3.4vw, 36px) 0;
  border-bottom: 1px solid var(--sandstone-deep);
}

.page-about .stage-num {
  font-size: clamp(2.4rem, 7vw, var(--fs-52));
  font-weight: 800;
  line-height: 0.86;
  letter-spacing: -0.03em;
  color: var(--sand);
  font-variant-numeric: tabular-nums;
}

.page-about .stage-title {
  margin: 0 0 10px;
  font-size: var(--fs-24);
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .stage-body p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.85;
  color: var(--space);
}

/* ---------- 流程步骤 ---------- */

.page-about .step-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .step {
  position: relative;
  min-width: 0;
  padding-top: 14px;
  border-top: 2px dashed var(--sand);
  outline: none;
}

.page-about .step:focus-visible {
  border-top-color: var(--danxia);
}

.page-about .step-num {
  display: block;
  margin-bottom: 10px;
  font-size: var(--fs-13);
  letter-spacing: 0.16em;
  color: var(--danxia);
  font-variant-numeric: tabular-nums;
}

.page-about .step-title {
  margin: 0 0 8px;
  font-size: var(--fs-18);
  font-weight: 800;
  line-height: 1.35;
  color: var(--ink);
}

.page-about .step-text {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--space);
}

.page-about .step-note {
  margin: 12px 0 0;
  padding-left: 11px;
  border-left: 2px solid var(--cyan-dark);
  font-size: var(--fs-13);
  line-height: 1.7;
  color: var(--cyan-dark);
  max-height: none;
  opacity: 1;
  overflow: visible;
}

.page-about .note-label {
  display: inline-block;
  margin-right: 8px;
  padding: 1px 7px;
  background-color: var(--cyan-dark);
  color: #fff;
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
}

.page-about .pull-quote {
  margin: clamp(30px, 4.5vw, 56px) 0 0;
  padding: clamp(20px, 3vw, 34px) clamp(20px, 3.2vw, 40px);
  border: var(--edge);
  background-color: var(--sand-light);
  box-shadow: var(--shadow-paper);
}

.page-about .pull-quote p {
  margin: 0;
  font-size: var(--fs-18);
  line-height: 1.75;
  font-weight: 700;
  color: var(--ink);
  max-width: 46ch;
}

/* ---------- 团队 ---------- */

.page-about .team-lede {
  margin: 0 0 clamp(22px, 3vw, 34px);
  font-size: var(--fs-18);
  line-height: 1.85;
}

.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .team-block {
  border: var(--edge);
  border-radius: var(--about-radius);
  padding: clamp(18px, 2.8vw, 26px);
  transition: transform var(--dur) var(--ease);
}

.page-about .team-block--edit {
  background-color: var(--space);
  color: var(--sandstone);
}

.page-about .team-block--check {
  background-color: var(--cyan-dark);
  color: #fff;
}

.page-about .team-block--tech {
  background-color: var(--danxia);
  color: #fff;
}

.page-about .team-block--ops {
  background-color: var(--sand);
  color: var(--ink);
}

.page-about .team-summary {
  display: flex;
  align-items: baseline;
  gap: 12px;
  cursor: pointer;
  list-style: none;
  font-weight: 800;
}

.page-about .team-summary::-webkit-details-marker {
  display: none;
}

.page-about .team-summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: var(--fs-18);
  opacity: 0.75;
}

.page-about .team-block[open] .team-summary::after {
  content: "–";
}

.page-about .team-count {
  font-size: var(--fs-34);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

.page-about .team-role {
  font-size: var(--fs-15);
  letter-spacing: 0.06em;
}

.page-about .team-desc {
  margin: 14px 0 0;
  padding-top: 14px;
  border-top: 1px solid currentColor;
  font-size: var(--fs-15);
  line-height: 1.8;
  opacity: 0.94;
}

/* ---------- 覆盖范围 ---------- */

.page-about .coverage-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 32px);
}

.page-about .coverage-cell {
  padding-top: 14px;
  border-top: 3px solid var(--danxia);
}

.page-about .coverage-num {
  display: block;
  font-size: clamp(2.2rem, 5vw, var(--fs-52));
  font-weight: 800;
  line-height: 0.92;
  letter-spacing: -0.03em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.page-about .coverage-label {
  display: block;
  margin-top: 6px;
  font-size: var(--fs-13);
  letter-spacing: 0.12em;
  color: var(--danxia);
}

.page-about .coverage-text {
  margin: 12px 0 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--space);
  max-width: 40ch;
}

/* ---------- 数据复核 ---------- */

.page-about .check-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(18px, 3vw, 30px);
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .check-item {
  padding-left: clamp(16px, 2.6vw, 26px);
  border-left: var(--edge);
}

.page-about .check-title {
  margin: 0 0 8px;
  font-size: var(--fs-18);
  font-weight: 800;
  color: var(--ink);
}

.page-about .check-text {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.85;
  color: var(--space);
  max-width: 64ch;
}

/* ---------- 结尾引导 ---------- */

.page-about .about-cta {
  margin-top: var(--about-section-gap);
  padding: clamp(26px, 4.4vw, 52px);
  background-color: var(--space);
  border: var(--edge);
  box-shadow: var(--shadow-paper);
  color: var(--sandstone);
}

.page-about .cta-eyebrow {
  margin: 0 0 10px;
  font-size: var(--fs-12);
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .cta-title {
  margin: 0 0 14px;
  font-size: clamp(1.5rem, 3.2vw, var(--fs-34));
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: #fff;
  max-width: 24ch;
}

.page-about .cta-text {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.85;
  color: var(--sandstone);
  max-width: 62ch;
}

.page-about .cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .cta-actions .btn {
  text-decoration: none;
}

.page-about .cta-contact {
  margin: 18px 0 0;
  font-family: var(--font-mono);
  font-size: var(--fs-13);
  letter-spacing: 0.02em;
  color: var(--sand);
  word-break: break-word;
}

/* ---------- 平板 ---------- */

@media (min-width: 700px) {
  .page-about .team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .check-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: clamp(22px, 3.4vw, 48px);
    row-gap: clamp(20px, 3vw, 34px);
  }
}

@media (min-width: 860px) {
  .page-about .who-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }

  .page-about .stage {
    grid-template-columns: minmax(96px, 140px) minmax(0, 1fr);
    gap: 0 clamp(20px, 3vw, 44px);
    align-items: start;
  }
}

/* ---------- 桌面 ---------- */

@media (min-width: 1024px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(40px, 5.5vw, 92px);
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
    padding: 0;
  }

  .page-about .rail-head {
    display: block;
  }

  .page-about .rail-list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding: 0;
  }

  .page-about .rail-link {
    border: 0;
    border-left: 2px solid var(--sandstone-deep);
    padding: 11px 0 11px 16px;
    letter-spacing: 0.14em;
    background-color: transparent;
  }

  .page-about .rail-link:hover,
  .page-about .rail-link:focus-visible {
    border-left-color: var(--danxia);
    color: var(--danxia);
  }

  .page-about .rail-link.is-active {
    border-left-color: var(--danxia);
    color: var(--ink);
    font-weight: 700;
  }

  .page-about .coverage-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: clamp(18px, 2.4vw, 32px);
  }

  .page-about .step-note {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height 220ms var(--ease), opacity 160ms var(--ease);
  }

  .page-about .step:hover .step-note,
  .page-about .step:focus .step-note,
  .page-about .step:focus-within .step-note {
    max-height: 240px;
    opacity: 1;
  }
}

@media (min-width: 1120px) {
  .page-about .step-list {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 0 20px;
  }

  .page-about .step-title {
    font-size: var(--fs-15);
  }

  .page-about .step-text {
    font-size: var(--fs-13);
  }

  .page-about .about-figure .media-frame {
    box-shadow: var(--shadow-paper);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .step-note,
  .page-about .rail-link,
  .page-about .team-block {
    transition: none;
  }
}