.page-about {
  padding: 4px 0 84px;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumbs {
  padding: 12px 0 0;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 26px;
  padding: 24px 0 36px;
  border-bottom: 1px solid var(--line-dark);
}

.page-about .hero-kicker {
  margin: 0 0 12px;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
  text-transform: uppercase;
}

.page-about .page-title {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-size: clamp(27px, 6.4vw, 50px);
  line-height: 1.12;
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--bright);
}

.page-about .page-lede {
  margin: 0;
  max-width: 40em;
  font-size: 16px;
  line-height: 1.9;
  color: var(--bright);
  opacity: .85;
}

.page-about .hero-panel {
  position: relative;
  padding: 20px 18px 18px;
  background: var(--navy-800);
  border: 1px solid var(--line-dark);
  border-radius: var(--radius-m);
}

.page-about .hero-panel::before {
  content: "";
  position: absolute;
  inset: 6px;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-s);
  pointer-events: none;
}

.page-about .hero-panel-title {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--amber);
}

.page-about .hero-facts {
  margin: 0 0 16px;
  display: grid;
  gap: 10px;
}

.page-about .hero-fact {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 8px;
  border-bottom: 1px dashed var(--line-soft);
}

.page-about .hero-fact dt {
  font-size: 13px;
  color: var(--frost);
}

.page-about .hero-fact dd {
  margin: 0;
  font-size: 15px;
  color: var(--bright);
  text-align: right;
}

.page-about .hero-num {
  font-family: var(--font-mono);
  letter-spacing: .04em;
  color: var(--amber);
}

.page-about .hero-stamp {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.page-about .hero-stamp-label {
  font-size: 13px;
  color: var(--frost);
}

.page-about .version-chip {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .06em;
  padding: 3px 12px;
  color: var(--amber);
  background: transparent;
  border: 1px solid var(--amber);
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .version-chip:hover,
.page-about .version-chip:focus-visible {
  color: var(--navy-900);
  background: var(--amber);
}

.page-about .version-chip[data-copied] {
  color: var(--navy-900);
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .hero-panel-note {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--frost);
}

/* ---------- 骨架：索引轴 + 内容流 ---------- */
.page-about .about-shell {
  display: grid;
  gap: 30px;
  padding-top: 34px;
}

.page-about .rail-title {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--frost);
}

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

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

.page-about .rail-nav a {
  flex: 0 0 auto;
  padding: 7px 13px;
  font-size: 13px;
  white-space: nowrap;
  color: var(--bright);
  background: var(--navy-800);
  border: 1px solid var(--line-dark);
  border-radius: var(--radius-pill);
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .rail-nav a:hover,
.page-about .rail-nav a:focus-visible {
  color: var(--cyan);
  border-color: var(--cyan);
}

.page-about .rail-nav a[aria-current="location"] {
  color: var(--navy-900);
  background: var(--cyan);
  border-color: var(--cyan);
}

/* ---------- 区块骨架 ---------- */
.page-about .about-sec {
  margin-bottom: 64px;
}

.page-about .about-sec:last-child {
  margin-bottom: 0;
}

.page-about .section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 14px;
  margin-bottom: 22px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .section-title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(20px, 3.4vw, 28px);
  line-height: 1.3;
  font-weight: 800;
  color: var(--bright);
}

.page-about .sub-title {
  margin: 30px 0 14px;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  color: var(--bright);
}

.page-about .sec-lead,
.page-about .sec-split {
  display: grid;
  gap: 24px;
}

.page-about .sec-lead-copy p,
.page-about .sec-split-copy p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.9;
  color: var(--bright);
  opacity: .88;
}

.page-about .sec-lead-copy p:last-child,
.page-about .sec-split-copy p:last-child {
  margin-bottom: 0;
}

/* ---------- 图片槽 ---------- */
.page-about .img-slot {
  display: block;
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line-dark);
  border-radius: var(--radius-m);
  background: var(--navy-800);
}

.page-about .img-slot img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .img-slot--wide {
  margin-bottom: 30px;
}

/* ---------- 栏目对照表 ---------- */
.page-about .column-map {
  border: 1px solid var(--line-dark);
  border-radius: var(--radius-m);
  background: var(--navy-800);
  overflow: hidden;
}

.page-about .column-row + .column-row {
  border-top: 1px solid var(--line-soft);
}

.page-about .column-row > summary {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr) 18px;
  grid-template-areas:
    "num name arrow"
    "num sum arrow";
  gap: 4px 12px;
  align-items: center;
  padding: 16px 16px 14px;
  cursor: pointer;
  list-style: none;
  transition: background var(--dur) var(--ease);
}

.page-about .column-row > summary::-webkit-details-marker {
  display: none;
}

.page-about .column-row > summary:hover {
  background: var(--navy-700);
}

.page-about .col-num {
  grid-area: num;
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--amber);
}

.page-about .col-name {
  grid-area: name;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 800;
  color: var(--bright);
}

.page-about .col-sum {
  grid-area: sum;
  font-size: 13px;
  line-height: 1.6;
  color: var(--frost);
}

.page-about .col-arrow {
  grid-area: arrow;
  position: relative;
  justify-self: end;
  width: 12px;
  height: 12px;
}

.page-about .col-arrow::before,
.page-about .col-arrow::after {
  content: "";
  position: absolute;
  background: var(--frost);
  transition: transform var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .col-arrow::before {
  left: 0;
  right: 0;
  top: 5px;
  height: 2px;
}

.page-about .col-arrow::after {
  top: 0;
  bottom: 0;
  left: 5px;
  width: 2px;
}

.page-about .column-row[open] .col-arrow::before,
.page-about .column-row[open] .col-arrow::after {
  background: var(--cyan);
}

.page-about .column-row[open] .col-arrow::after {
  transform: scaleY(0);
}

.page-about .col-detail {
  padding: 2px 16px 18px;
}

.page-about .col-detail p {
  margin: 0 0 12px;
  font-size: 14px;
  line-height: 1.85;
  color: var(--bright);
  opacity: .82;
}

.page-about .col-link {
  display: inline-block;
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--amber);
  text-decoration: none;
  border-bottom: 1px solid var(--amber-deep);
  padding-bottom: 2px;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

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

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  position: relative;
  margin: 0;
  padding: 6px 0 0 30px;
  list-style: none;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 12px;
  bottom: 20px;
  width: 2px;
  background: linear-gradient(180deg, var(--amber) 0%, var(--frost) 42%, rgba(127, 168, 201, .22) 100%);
}

.page-about .timeline-item {
  position: relative;
  margin-bottom: 18px;
}

.page-about .timeline-item:last-child {
  margin-bottom: 0;
}

.page-about .timeline-node {
  position: absolute;
  left: -30px;
  top: 22px;
  width: 12px;
  height: 12px;
  background: var(--navy-900);
  border: 2px solid var(--amber);
  box-sizing: border-box;
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .timeline-item:hover .timeline-node,
.page-about .timeline-item:focus-within .timeline-node {
  background: var(--amber);
  border-color: var(--amber);
  box-shadow: 0 0 0 5px rgba(242, 163, 60, .16);
}

.page-about .timeline-card {
  padding: 16px 18px 18px;
  color: var(--ink);
}

.page-about .timeline-ver {
  margin: 0 0 4px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--amber-deep);
}

.page-about .timeline-when {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: .1em;
  color: rgba(26, 22, 20, .58);
}

.page-about .timeline-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--ink);
}

/* ---------- 校对步骤 ---------- */
.page-about .steps {
  margin: 0 0 22px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 2px;
}

.page-about .step {
  position: relative;
  padding: 16px 0 16px 46px;
  border-top: 1px solid var(--line-soft);
}

.page-about .step:last-child {
  border-bottom: 1px solid var(--line-soft);
}

.page-about .step-num {
  position: absolute;
  left: 0;
  top: 17px;
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--amber);
}

.page-about .step-title {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 800;
  color: var(--bright);
}

.page-about .step-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--bright);
  opacity: .82;
}

.page-about .rhythm-note {
  margin: 0;
  padding: 16px 18px;
  font-size: 14px;
  line-height: 1.9;
  color: var(--bright);
  background: var(--navy-700);
  border-left: 3px solid var(--cyan);
  border-radius: 0 var(--radius-s) var(--radius-s) 0;
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  gap: 14px;
}

.page-about .team-card {
  padding: 20px 18px;
  background: var(--navy-800);
  border: 1px solid var(--line-dark);
  border-radius: var(--radius-m);
  border-top: 2px solid var(--amber);
}

.page-about .team-num {
  margin: 0 0 4px;
  font-size: 34px;
  line-height: 1;
  font-weight: 700;
  color: var(--amber);
}

.page-about .team-role {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 800;
  color: var(--bright);
}

.page-about .team-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--bright);
  opacity: .82;
}

/* ---------- 站点信息 ---------- */
.page-about .info-panel {
  padding: 22px 18px;
  background: var(--paper);
  border: 1px solid var(--paper-shadow);
  border-radius: var(--radius-m);
  box-shadow: 0 3px 0 var(--paper-shadow), 0 12px 26px rgba(0, 0, 0, .22);
}

.page-about .info-list {
  margin: 0;
  display: grid;
  gap: 0;
}

.page-about .info-row {
  display: grid;
  gap: 4px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line-paper);
}

.page-about .info-row:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .info-row:first-child {
  padding-top: 0;
}

.page-about .info-row dt {
  font-size: 12px;
  letter-spacing: .1em;
  color: rgba(26, 22, 20, .6);
}

.page-about .info-row dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink);
}

.page-about .info-icp {
  letter-spacing: .04em;
  color: var(--amber-deep);
}

.page-about .info-note {
  margin: 18px 0 0;
  padding-top: 14px;
  border-top: 1px dashed var(--line-paper);
  font-size: 13px;
  line-height: 1.8;
  color: rgba(26, 22, 20, .68);
}

.page-about .next-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

/* ---------- 中屏 ---------- */
@media (min-width: 720px) {
  .page-about .column-row > summary {
    grid-template-columns: 62px 150px minmax(0, 1fr) 20px;
    grid-template-areas: "num name sum arrow";
    gap: 16px;
    align-items: center;
    padding: 18px 20px;
  }

  .page-about .col-detail {
    padding: 4px 20px 20px 98px;
  }

  .page-about .team-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .info-row {
    grid-template-columns: 118px minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }
}

/* ---------- 宽屏 ---------- */
@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, .82fr);
    gap: 54px;
    align-items: end;
    padding: 40px 0 52px;
  }

  .page-about .about-shell {
    grid-template-columns: 186px minmax(0, 1fr);
    gap: 46px;
    padding-top: 44px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 108px;
    align-self: start;
  }

  .page-about .rail-nav {
    flex-direction: column;
    overflow: visible;
    padding-bottom: 0;
    gap: 4px;
  }

  .page-about .rail-nav a {
    display: block;
    padding: 8px 12px;
    font-size: 13px;
    border-color: transparent;
    border-left: 2px solid var(--line-dark);
    border-radius: 0 var(--radius-s) var(--radius-s) 0;
    background: transparent;
  }

  .page-about .rail-nav a:hover,
  .page-about .rail-nav a:focus-visible {
    background: var(--navy-800);
    border-left-color: var(--amber);
  }

  .page-about .rail-nav a[aria-current="location"] {
    color: var(--cyan);
    background: var(--navy-800);
    border-color: var(--cyan);
    border-left-color: var(--cyan);
  }

  .page-about .sec-lead {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, .75fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .sec-split {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .timeline {
    padding-left: 78px;
  }

  .page-about .timeline::before {
    left: 30px;
  }

  .page-about .timeline-node {
    left: -54px;
    top: 24px;
  }

  .page-about .timeline-item:nth-child(1) .timeline-card { margin-left: 0; }
  .page-about .timeline-item:nth-child(2) .timeline-card { margin-left: 8px; }
  .page-about .timeline-item:nth-child(3) .timeline-card { margin-left: 16px; }
  .page-about .timeline-item:nth-child(4) .timeline-card { margin-left: 24px; }

  .page-about .timeline-card {
    transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
  }

  .page-about .timeline-item:hover .timeline-card {
    transform: translateY(-2px);
    box-shadow: 0 4px 0 var(--paper-shadow), 0 14px 26px rgba(0, 0, 0, .26);
  }

  .page-about .img-slot--wide {
    margin-bottom: 38px;
  }

  .page-about .info-panel {
    padding: 28px 26px;
  }
}

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .timeline-card,
  .page-about .timeline-node,
  .page-about .col-arrow::before,
  .page-about .col-arrow::after,
  .page-about .rail-nav a,
  .page-about .version-chip {
    transition: none !important;
  }

  .page-about .timeline-item:hover .timeline-card {
    transform: none;
  }
}