.page-about {
  --rail-w: 56px;
  --about-gap: clamp(28px, 5vw, 64px);
  background: var(--ink);
  color: var(--cold);
  font-family: var(--font-sans);
  line-height: 1.75;
}

.page-about .about-section {
  padding: clamp(46px, 8vw, 96px) 0;
  border-top: 1px solid var(--line);
}

.page-about .section__title {
  color: var(--cold);
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: .01em;
}

.page-about .section__lead {
  color: var(--slate);
  max-width: 54ch;
}

.page-about .prose p {
  color: var(--ink-veil);
  max-width: 42ch;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(38px, 7vw, 92px) 0 clamp(34px, 5vw, 62px);
  background: linear-gradient(180deg, var(--ink-deep) 0%, var(--ink) 100%);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image: repeating-linear-gradient(90deg, rgba(124, 141, 166, .18) 0 1px, transparent 1px 64px);
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 14%, #000 86%, transparent);
  mask-image: linear-gradient(90deg, transparent, #000 14%, #000 86%, transparent);
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--gold-line);
  opacity: .55;
}

.page-about .about-hero__inner {
  position: relative;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(29px, 6.2vw, 60px);
  line-height: 1.14;
  letter-spacing: .01em;
  color: var(--cold);
}

.page-about .about-hero__lead {
  margin: 20px 0 0;
  max-width: 44ch;
  font-size: clamp(15px, 1.5vw, 17px);
  color: var(--ink-veil);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: clamp(26px, 4vw, 42px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-hero__fact {
  background: rgba(18, 41, 63, .74);
  padding: 15px 16px;
}

.page-about .about-hero__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(19px, 2.6vw, 26px);
  line-height: 1.2;
  color: var(--gold);
  letter-spacing: .02em;
}

.page-about .about-hero__label {
  display: block;
  margin-top: 4px;
  font-size: 12.5px;
  color: var(--slate);
  letter-spacing: .04em;
}

/* ---------- 起点 ---------- */
.page-about .origin-split {
  display: grid;
  gap: var(--about-gap);
}

.page-about .origin-head .section__title {
  margin-bottom: 18px;
}

.page-about .origin-note {
  align-self: start;
  border: 1px solid var(--line);
  border-left: 2px solid var(--gold);
  background: rgba(6, 16, 25, .7);
  padding: clamp(18px, 3vw, 26px);
}

.page-about .origin-note__label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .08em;
  color: var(--champagne);
  transform: skewX(-2deg);
}

.page-about .origin-note__text {
  margin: 0;
  font-size: 14.5px;
  color: var(--slate);
}

/* ---------- 阶段导轨 ---------- */
.page-about .stage-rail {
  margin: clamp(22px, 3vw, 34px) 0 clamp(26px, 4vw, 46px);
}

.page-about .stage-rail__list {
  list-style: none;
  margin: 0;
  padding: 0 0 10px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
}

.page-about .stage-rail__link {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 9px 15px;
  border: 1px solid var(--line);
  background: rgba(18, 41, 63, .6);
  color: var(--cold);
  text-decoration: none;
  font-size: 13px;
  white-space: nowrap;
  scroll-snap-align: start;
  transition: border-color 180ms var(--ease), color 180ms var(--ease), background 180ms var(--ease);
}

.page-about .stage-rail__link:hover,
.page-about .stage-rail__link:focus-visible {
  border-color: var(--gold);
  color: var(--gold);
  background: var(--gold-tint);
}

.page-about .stage-rail__num {
  font-family: var(--font-mono);
  color: var(--gold);
  letter-spacing: .06em;
}

/* ---------- 竖向时间轴 ---------- */
.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .timeline__item {
  position: relative;
  display: grid;
  grid-template-columns: var(--rail-w) minmax(0, 1fr);
  gap: 16px;
  padding-bottom: clamp(30px, 4vw, 46px);
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  top: 56px;
  bottom: 0;
  left: calc(var(--rail-w) / 2 - .5px);
  width: 1px;
  background: linear-gradient(180deg, var(--gold), rgba(212, 175, 55, .12));
}

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

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

.page-about .timeline__marker {
  width: 56px;
  height: 56px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background: var(--ink-deep);
  box-shadow: 0 0 0 6px rgba(11, 27, 43, .9);
  justify-self: center;
}

.page-about .timeline__code {
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--gold);
  letter-spacing: .06em;
}

.page-about .timeline__body {
  max-width: 660px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--line-strong);
  background: rgba(18, 41, 63, .5);
  padding: clamp(18px, 3vw, 28px);
}

.page-about .timeline__period {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .08em;
  color: var(--slate);
  transform: skewX(-2deg);
}

.page-about .timeline__title {
  margin: 8px 0 0;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: clamp(19px, 2.4vw, 24px);
  line-height: 1.35;
  color: var(--cold);
}

.page-about .timeline__text {
  margin: 10px 0 0;
  color: var(--ink-veil);
  font-size: 15px;
  max-width: 42ch;
}

.page-about .timeline__points {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  gap: 7px;
}

.page-about .timeline__points li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  color: var(--slate);
}

.page-about .timeline__points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .68em;
  width: 6px;
  height: 1px;
  background: var(--gold);
}

/* ---------- 团队 ---------- */
.page-about .team-split {
  display: grid;
  gap: var(--about-gap);
}

.page-about .team-roles {
  display: grid;
  gap: 14px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .role {
  border: 1px solid var(--line);
  border-left: 3px solid var(--gold);
  background: rgba(18, 41, 63, .5);
  padding: 18px 20px;
  transition: background 200ms var(--ease), border-left-color 200ms var(--ease);
}

.page-about .role:hover {
  background: rgba(18, 41, 63, .86);
  border-left-color: var(--champagne);
}

.page-about .role__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .role__num {
  font-family: var(--font-mono);
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1;
  color: var(--champagne);
}

.page-about .role__name {
  margin: 0;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 14.5px;
  letter-spacing: .1em;
  color: var(--cold);
}

.page-about .role__detail {
  margin: 10px 0 0;
  font-size: 14.5px;
  color: var(--slate);
  transition: color 200ms var(--ease);
}

.page-about .role:hover .role__detail,
.page-about .role:focus-within .role__detail {
  color: var(--ink-veil);
}

.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--line);
  background: rgba(6, 16, 25, .6);
  padding: 10px;
}

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

.page-about .about-figure .figure__caption {
  margin: 10px 0 0;
  font-size: 12.5px;
  color: var(--slate);
}

.page-about .team-figure {
  align-self: start;
}

/* ---------- 数据校验 ---------- */
.page-about .verify-grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .verify-copy .section__title {
  max-width: 18ch;
}

.page-about .verify-copy .prose {
  margin-top: 16px;
}

.page-about .verify-steps {
  list-style: none;
  margin: clamp(30px, 4vw, 48px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .verify-step {
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  background: var(--ink);
  padding: 18px 4px;
}

.page-about .verify-step__num {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--gold);
  padding-top: 3px;
}

.page-about .verify-step__title {
  margin: 0;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 15.5px;
  color: var(--cold);
}

.page-about .verify-step__text {
  margin: 6px 0 0;
  font-size: 14px;
  color: var(--slate);
}

/* ---------- 合作生态 ---------- */
.page-about .about-eco .segment {
  margin-bottom: clamp(20px, 3vw, 30px);
}

.page-about .about-eco .segment__panel {
  color: var(--ink-veil);
  font-size: 15px;
  max-width: 62ch;
}

.page-about .about-eco .segment__panel[hidden] {
  display: none;
}

.page-about .eco-list {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 9px;
}

.page-about .eco-list li {
  position: relative;
  padding-left: 18px;
  font-size: 14.5px;
  color: var(--slate);
}

.page-about .eco-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .68em;
  width: 8px;
  height: 1px;
  background: var(--teal);
}

.page-about .paper-block {
  background: var(--paper);
  color: var(--ink);
  border-left: 3px solid var(--gold);
  padding: clamp(20px, 3vw, 30px);
  margin-bottom: 18px;
}

.page-about .paper-block__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(16px, 2vw, 19px);
  color: var(--ink-deep);
  letter-spacing: .02em;
}

.page-about .paper-block p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(11, 27, 43, .88);
}

.page-about .report-card {
  border: 1px solid var(--line);
  background: rgba(18, 41, 63, .5);
  padding: 16px 20px;
}

.page-about .report-card summary {
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--gold);
}

.page-about .report-card summary::marker {
  color: var(--gold);
}

.page-about .report-card summary:focus-visible {
  outline: 2px solid var(--teal);
  outline-offset: 3px;
}

.page-about .report-card__list {
  margin: 14px 0 0;
  padding-left: 20px;
  display: grid;
  gap: 9px;
  font-size: 14.5px;
  color: var(--slate);
}

/* ---------- 服务范围 ---------- */
.page-about .reach-grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(132px, 1fr));
  gap: 1px;
  margin-top: clamp(22px, 3vw, 34px);
  background: var(--line);
  border: 1px solid var(--line);
}

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

.page-about .stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(20px, 3vw, 28px);
  line-height: 1.2;
  color: var(--cold);
  letter-spacing: .02em;
}

.page-about .stat__label {
  display: block;
  margin-top: 4px;
  font-size: 12.5px;
  color: var(--slate);
  letter-spacing: .04em;
}

.page-about .reach-figure {
  align-self: center;
}

/* ---------- 结尾引导 ---------- */
.page-about .about-next {
  padding: clamp(46px, 7vw, 88px) 0;
  background: linear-gradient(180deg, var(--ink) 0%, var(--ink-deep) 100%);
  border-top: 1px solid var(--line);
}

.page-about .about-next__inner {
  border: 1px solid var(--line-strong);
  background: rgba(18, 41, 63, .45);
  padding: clamp(24px, 4vw, 46px);
}

.page-about .about-next__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(22px, 3.4vw, 34px);
  line-height: 1.25;
  color: var(--cold);
}

.page-about .about-next__text {
  margin: 14px 0 0;
  max-width: 48ch;
  font-size: 15px;
  color: var(--ink-veil);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about {
    --rail-w: 132px;
  }

  .page-about .timeline__item {
    grid-template-columns: var(--rail-w) minmax(0, 1fr);
    gap: 24px;
  }

  .page-about .timeline__item:nth-child(even) .timeline__body {
    margin-left: clamp(12px, 4vw, 56px);
  }

  .page-about .verify-step {
    grid-template-columns: 64px minmax(0, 1fr);
    padding: 22px 8px;
  }

  .page-about .about-next__inner {
    display: grid;
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    align-items: end;
    column-gap: clamp(24px, 4vw, 48px);
  }

  .page-about .about-next__actions {
    margin-top: 0;
    justify-content: flex-end;
  }
}

@media (min-width: 900px) {
  .page-about .origin-split {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .team-split {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    align-items: start;
  }

  .page-about .verify-grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, .9fr);
    align-items: center;
  }

  .page-about .reach-grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, .8fr);
    align-items: center;
  }

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

  .page-about .verify-step {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .page-about .verify-step__num {
    padding-top: 0;
  }
}

@media (min-width: 1080px) {
  .page-about .about-eco .segment__panel {
    max-width: 74ch;
  }

  .page-about .team-figure {
    margin-top: clamp(10px, 2vw, 34px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .role,
  .page-about .role__detail,
  .page-about .stage-rail__link {
    transition: none;
  }
}