.page-about {
  --about-rail-w: 168px;
  --about-text: rgba(242, 246, 248, 0.76);
  --about-text-dim: rgba(124, 141, 166, 0.95);
  padding-bottom: clamp(48px, 8vw, 96px);
}

/* ---------- 面包屑与开篇 ---------- */
.page-about .breadcrumb {
  padding-top: clamp(18px, 3vw, 32px);
}

.page-about .about-lede {
  position: relative;
  padding: clamp(28px, 5vw, 56px) 0 clamp(24px, 4vw, 36px);
  border-bottom: 1px solid var(--line);
}

.page-about .about-lede::before {
  content: "";
  position: absolute;
  z-index: -1;
  inset: -40px -6% auto -6%;
  height: 260px;
  background:
    radial-gradient(58% 100% at 18% 0%, rgba(38, 224, 214, 0.13), transparent 72%),
    radial-gradient(46% 88% at 88% 8%, rgba(255, 107, 44, 0.1), transparent 72%);
  pointer-events: none;
}

.page-about .lede-index {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .lede-title {
  margin: 0;
  font-size: clamp(36px, 8vw, 72px);
  font-weight: 900;
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--snow);
}

.page-about .lede-copy {
  margin: 20px 0 0;
  max-width: 36em;
  font-size: clamp(15px, 1.7vw, 17px);
  line-height: 1.85;
  color: var(--about-text);
}

/* ---------- 开篇关键数据 ---------- */
.page-about .lede-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(26px, 4vw, 40px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .lede-stat {
  background: var(--slate);
  padding: 16px 18px 18px;
}

.page-about .stat-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(28px, 5vw, 40px);
  line-height: 1;
  color: var(--sand);
}

.page-about .stat-label {
  display: block;
  margin-top: 8px;
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  padding-top: clamp(30px, 5vw, 60px);
}

/* ---------- 左侧刻度栏（移动端为横向芯片条） ---------- */
.page-about .about-rail {
  position: relative;
}

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

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

.page-about .rail-item {
  flex: 0 0 auto;
}

.page-about .rail-link {
  display: block;
  padding: 7px 12px;
  font-size: 13px;
  line-height: 1.3;
  white-space: nowrap;
  color: var(--mist);
  text-decoration: none;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: color 0.2s ease, border-color 0.2s ease;
}

.page-about .rail-link:hover,
.page-about .rail-link.is-active {
  color: var(--cyan);
  border-color: var(--cyan);
}

.page-about .rail-num {
  display: inline;
  margin-right: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--sand);
}

/* ---------- 章节 ---------- */
.page-about .about-chapters {
  min-width: 0;
}

.page-about .chapter {
  position: relative;
  padding-bottom: clamp(38px, 6vw, 68px);
}

.page-about .chapter + .chapter {
  padding-top: clamp(34px, 5vw, 56px);
}

.page-about .chapter + .chapter::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: min(100%, 420px);
  height: 1px;
  background: repeating-linear-gradient(90deg, var(--line) 0 12px, transparent 12px 24px);
  transform: skewX(-32deg);
  transform-origin: left center;
}

.page-about .section-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 14px;
  margin-bottom: clamp(20px, 3vw, 28px);
  border-bottom: 1px solid var(--line);
}

.page-about .sec-num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--sand);
}

.page-about .sec-title {
  margin: 0;
  font-size: clamp(21px, 3.2vw, 30px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--snow);
}

.page-about .chapter-summary {
  margin: 0 0 clamp(22px, 3vw, 32px);
  padding-left: 16px;
  max-width: 34em;
  font-size: clamp(15px, 1.7vw, 17px);
  line-height: 1.85;
  color: rgba(242, 246, 248, 0.84);
  border-left: 2px solid var(--cyan);
}

.page-about .body-text {
  margin: 0;
  max-width: 36em;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--about-text);
}

.page-about .chapter-more {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  margin: clamp(22px, 3vw, 30px) 0 0;
}

.page-about .more-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--clay);
}

.page-about .more-link {
  font-size: 14px;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(38, 224, 214, 0.4);
  padding-bottom: 2px;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.page-about .more-link:hover {
  color: var(--snow);
  border-color: var(--orange);
}

/* ---------- 01 时间线 ---------- */
.page-about .timeline {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .tl-item {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: 18px 0 18px 24px;
  border-bottom: 1px dashed rgba(46, 58, 77, 0.85);
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 26px;
  width: 8px;
  height: 8px;
  background: var(--moss);
  transform: rotate(45deg);
}

.page-about .tl-year {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--sand);
}

.page-about .tl-title {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--snow);
}

.page-about .tl-text {
  margin: 0;
  max-width: 36em;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--about-text);
}

/* ---------- 02 团队 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
}

.page-about .team-roles {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .role-item {
  background: var(--slate);
  padding: 14px 16px 16px;
  transition: background-color 0.25s ease;
}

.page-about .role-item:hover,
.page-about .role-item:focus-within {
  background: rgba(38, 224, 214, 0.07);
}

.page-about .role-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 26px;
  line-height: 1.1;
  color: var(--sand);
}

.page-about .role-name {
  display: block;
  margin-top: 4px;
  font-size: 13.5px;
  color: var(--snow);
}

.page-about .role-note {
  display: block;
  max-height: 0;
  margin-top: 0;
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--mist);
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, opacity 0.3s ease, margin-top 0.3s ease;
}

.page-about .role-item:hover .role-note,
.page-about .role-item:focus-within .role-note {
  max-height: 90px;
  margin-top: 8px;
  opacity: 1;
}

.page-about .team-figure {
  aspect-ratio: 3 / 2;
  margin: 0;
  background: var(--slate);
  overflow: hidden;
}

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

/* ---------- 03 数据链路 ---------- */
.page-about .flow {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .flow-step {
  position: relative;
  padding: 0 0 22px 52px;
}

.page-about .flow-step:last-child {
  padding-bottom: 0;
}

.page-about .flow-step::before {
  content: "";
  position: absolute;
  left: 18px;
  top: 40px;
  bottom: 0;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan-soft), var(--line));
}

.page-about .flow-step:last-child::before {
  display: none;
}

.page-about .flow-node {
  position: absolute;
  left: 0;
  top: 0;
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--cyan);
  background: var(--slate);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%);
}

.page-about .flow-title {
  margin: 6px 0 5px;
  font-size: 15.5px;
  font-weight: 700;
  color: var(--snow);
}

.page-about .flow-text {
  margin: 0;
  max-width: 34em;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--about-text);
}

.page-about .flow-figure {
  margin: clamp(24px, 4vw, 36px) 0 0;
  background: var(--slate);
  overflow: hidden;
}

.page-about .flow-figure img {
  display: block;
  width: 100%;
  max-width: 560px;
  height: auto;
  object-fit: cover;
}

/* ---------- 04 覆盖范围 ---------- */
.page-about .cov-banner {
  margin: 0 0 clamp(22px, 3vw, 32px);
  background: var(--slate);
  overflow: hidden;
}

.page-about .cov-banner img {
  display: block;
  width: 100%;
  height: auto;
  max-height: 340px;
  object-fit: cover;
}

.page-about .cov-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0 0 clamp(26px, 4vw, 40px);
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .cov-fact {
  background: var(--night);
  padding: 16px 18px;
}

.page-about .cov-fact dt {
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.page-about .cov-fact dd {
  margin: 8px 0 0;
  font-size: 13px;
  color: var(--about-text);
}

.page-about .cov-fact .data-num {
  font-size: 26px;
  color: var(--sand);
}

.page-about .tier-head {
  margin: 0 0 16px;
  font-size: 16px;
  font-weight: 700;
  color: var(--snow);
}

.page-about .tier-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .tier-item {
  padding: 16px 18px;
  background: var(--slate);
  border-left: 2px solid var(--line);
  transition: border-color 0.25s ease;
}

.page-about .tier-item:hover {
  border-left-color: var(--cyan);
}

.page-about .tier-text {
  margin: 10px 0 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--about-text);
}

/* ---------- 05 合作伙伴 ---------- */
.page-about .partner-list {
  border-top: 1px solid var(--line);
}

.page-about .partner {
  border-bottom: 1px solid var(--line);
}

.page-about .partner-toggle {
  display: flex;
  align-items: baseline;
  gap: 12px;
  width: 100%;
  padding: 18px 40px 18px 0;
  background: none;
  border: 0;
  text-align: left;
  color: var(--snow);
  cursor: pointer;
}

.page-about .partner-count {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 24px;
  line-height: 1;
  color: var(--sand);
}

.page-about .partner-name {
  font-size: 15.5px;
  font-weight: 700;
}

.page-about .partner-toggle:hover .partner-name {
  color: var(--cyan);
}

.page-about .partner .panel-body p {
  margin: 0;
  max-width: 36em;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--about-text);
}

/* ---------- 06 里程碑 ---------- */
.page-about .mile-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .mile-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: 18px 0;
  border-bottom: 1px dashed rgba(46, 58, 77, 0.85);
}

.page-about .mile-mark {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--orange);
}

.page-about .mile-title {
  margin: 0 0 5px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--snow);
}

.page-about .mile-text {
  margin: 0;
  max-width: 36em;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--about-text);
}

.page-about .about-cta {
  margin-top: clamp(30px, 4vw, 48px);
  padding: clamp(22px, 3vw, 32px);
  background: var(--slate);
  border: 1px solid var(--line);
  border-left: 2px solid var(--cyan);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .cta-text {
  margin: 0 0 20px;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--about-text);
}

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

/* ---------- 断点 ---------- */
@media (min-width: 720px) {
  .page-about .lede-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .tl-item {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: 24px;
    padding-left: 24px;
  }

  .page-about .tier-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0;
    border: 1px solid var(--line);
    background: var(--line);
    grid-auto-rows: 1fr;
  }

  .page-about .tier-item {
    border-left: 0;
    border-top: 3px solid var(--line);
  }

  .page-about .tier-item:hover {
    border-left-color: transparent;
    border-top-color: var(--cyan);
  }

  .page-about .mile-item {
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 24px;
  }
}

@media (min-width: 820px) {
  .page-about .team-grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .cov-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(36px, 5vw, 72px);
  }

  .page-about .about-rail::before {
    content: "";
    position: absolute;
    left: 13px;
    top: 10px;
    bottom: 40px;
    width: 1px;
    background: linear-gradient(180deg, var(--cyan) 0%, var(--line) 20%, var(--line) 100%);
    opacity: 0.75;
  }

  .page-about .rail-sticky {
    position: sticky;
    top: calc(var(--header-h) + 32px);
  }

  .page-about .rail-list {
    display: block;
    overflow: visible;
    padding: 0;
  }

  .page-about .rail-item {
    margin-bottom: 22px;
  }

  .page-about .rail-link {
    position: relative;
    padding: 0 0 0 30px;
    white-space: normal;
    border: 0;
    border-radius: 0;
    font-size: 13px;
    line-height: 1.4;
    background: none;
  }

  .page-about .rail-link::before {
    content: "";
    position: absolute;
    left: 9px;
    top: 11px;
    width: 9px;
    height: 1px;
    background: var(--line);
    transition: width 0.2s ease, background-color 0.2s ease;
  }

  .page-about .rail-link:hover,
  .page-about .rail-link.is-active {
    border-color: transparent;
    color: var(--cyan);
  }

  .page-about .rail-link:hover::before,
  .page-about .rail-link.is-active::before {
    width: 16px;
    background: var(--cyan);
  }

  .page-about .rail-num {
    display: block;
    margin: 0 0 3px;
    font-size: 11px;
    color: var(--sand);
  }
}

@media (hover: none) {
  .page-about .role-note {
    max-height: 90px;
    margin-top: 8px;
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .rail-link,
  .page-about .role-item,
  .page-about .role-note,
  .page-about .tier-item,
  .page-about .more-link {
    transition: none;
  }
}