.page-about {
  --about-rail-w: 220px;
  --about-rule: 1px solid var(--line);
  display: block;
  padding-bottom: clamp(56px, 9vw, 150px);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  padding-top: clamp(18px, 3vw, 34px);
  padding-bottom: clamp(18px, 3vw, 34px);
}

/* ---------- 首屏册页 ---------- */
.page-about .about-hero {
  border-top: var(--about-rule);
  border-bottom: var(--about-rule);
  padding: clamp(34px, 6vw, 84px) 0 clamp(40px, 7vw, 104px);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(30px, 5vw, 68px);
  align-items: end;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(32px, 6.2vw, 74px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--paper);
  text-wrap: balance;
}

.page-about .about-hero__lede {
  margin: 22px 0 0;
  max-width: 42ch;
  font-size: 17px;
  line-height: 1.75;
  color: var(--body);
}

.page-about .about-hero__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 26px;
  margin: 32px 0 0;
  padding: 18px 0 0;
  border-top: var(--about-rule);
  list-style: none;
}

.page-about .about-hero__fact {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--body-dim);
}

.page-about .about-hero__fact b {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 600;
  color: var(--gold-light);
}

.page-about .about-hero__media {
  margin: 0;
  border: 2px solid var(--gold);
  box-shadow: var(--shadow-card), inset 0 0 0 1px var(--foil-line);
  background: var(--graphite);
}

.page-about .about-hero__media .media-frame__inner {
  aspect-ratio: 3 / 2;
  overflow: hidden;
}

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

.page-about .media-frame__caption {
  padding: 14px 18px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--body-dim);
  border-top: var(--about-rule);
}

/* ---------- 主体：左栏 + 右栏 ---------- */
.page-about .about-body {
  padding-top: clamp(48px, 8vw, 118px);
}

.page-about .about-body__layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 56px);
  align-items: start;
}

.page-about .about-rail {
  display: none;
}

.page-about .about-rail__coord {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin: 0 0 10px;
}

.page-about .about-rail__city {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 20px;
  letter-spacing: 0.06em;
  color: var(--paper);
}

.page-about .about-rail__role {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--gold);
}

.page-about .about-rail__nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin-top: 28px;
  border-left: var(--about-rule);
}

.page-about .about-rail__link {
  position: relative;
  display: block;
  padding: 10px 0 10px 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--body-dim);
  text-decoration: none;
  transition: color 0.3s var(--ease), padding-left 0.3s var(--ease);
}

.page-about .about-rail__link::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 50%;
  width: 7px;
  height: 7px;
  margin-top: -3.5px;
  background: transparent;
  border: 1px solid var(--gold-deep);
  transform: rotate(45deg);
  transition: background 0.3s var(--ease), border-color 0.3s var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--gold-light);
  padding-left: 22px;
}

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

/* ---------- 章节 ---------- */
.page-about .about-sec {
  padding-block: clamp(42px, 7vw, 100px);
  border-top: var(--about-rule);
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .about-sec:first-child {
  padding-top: 0;
  border-top: 0;
}

.page-about .about-sec__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(25px, 3.6vw, 44px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--paper);
  text-wrap: balance;
}

.page-about .about-sec__p {
  margin: 20px 0 0;
  max-width: 62ch;
  font-size: 17px;
  line-height: 1.75;
  color: var(--body);
}

.page-about .about-sec__p--after {
  margin-top: 30px;
  padding-top: 22px;
  border-top: var(--about-rule);
}

.page-about .about-inline-link {
  color: var(--gold-light);
  text-decoration: none;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 1px;
  transition: color 0.3s var(--ease), border-color 0.3s var(--ease);
}

.page-about .about-inline-link:hover,
.page-about .about-inline-link:focus-visible {
  color: var(--foil);
  border-bottom-color: var(--gold);
}

/* ---------- 双城 ---------- */
.page-about .about-cities {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  margin-top: clamp(28px, 4vw, 44px);
}

.page-about .about-city {
  position: relative;
  padding: 26px 22px 28px;
  background: var(--graphite);
  border: var(--about-rule);
  box-shadow: inset 0 0 0 1px var(--foil-line);
}

.page-about .about-city--hub {
  background: var(--graphite-2);
  border-color: var(--line-strong);
}

.page-about .about-city--hub::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 54px;
  height: 4px;
  background: var(--metal);
}

.page-about .about-city__tag {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--gold);
}

.page-about .about-city__name {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 22px;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .about-city__text {
  margin: 14px 0 0;
  font-size: 16px;
  line-height: 1.75;
  color: var(--body);
}

/* ---------- 发展阶段 ---------- */
.page-about .about-phases {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 40px);
  margin-top: clamp(26px, 4vw, 42px);
}

.page-about .about-phases__figure {
  margin: 0;
  border: var(--about-rule);
  background: var(--graphite);
  align-self: start;
}

.page-about .about-phases__figure .media-frame__inner {
  aspect-ratio: 1 / 1;
  overflow: hidden;
}

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

.page-about .about-track {
  overflow-x: auto;
  overscroll-behavior-x: contain;
  scroll-snap-type: x proximity;
  padding: 14px 0 18px;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-track:focus-visible {
  outline: 2px solid var(--teal);
  outline-offset: 6px;
}

.page-about .about-track__list {
  display: flex;
  gap: 18px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-phase {
  position: relative;
  flex: 0 0 min(310px, 78vw);
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  padding: 30px 20px 26px;
  background: var(--graphite);
  border: var(--about-rule);
  border-top: 2px solid var(--gold-deep);
  box-shadow: inset 0 0 0 1px var(--foil-line);
  transition: transform 0.4s var(--ease), border-color 0.4s var(--ease);
}

.page-about .about-phase::before {
  content: "";
  position: absolute;
  top: -7px;
  left: 20px;
  width: 10px;
  height: 10px;
  background: var(--gold);
  transform: rotate(45deg);
}

.page-about .about-phase:hover,
.page-about .about-phase:focus-within {
  transform: translateY(-6px);
  border-top-color: var(--gold-light);
}

.page-about .about-phase__no {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--body-dim);
}

.page-about .about-phase__year {
  margin: 16px 0 0;
  font-size: 34px;
  line-height: 1;
  color: var(--gold-light);
}

.page-about .about-phase__name {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 21px;
  color: var(--paper);
}

.page-about .about-phase__text {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--body);
}

/* ---------- 服务原则 ---------- */
.page-about .about-principles {
  margin: clamp(26px, 4vw, 42px) 0 0;
  padding: 0;
  list-style: none;
  border-top: var(--about-rule);
}

.page-about .about-principle {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  padding: clamp(22px, 3vw, 32px) 0;
  border-bottom: var(--about-rule);
}

.page-about .about-principle__no {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--gold);
}

.page-about .about-principle__name {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 23px;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .about-principle__text {
  margin: 0;
  max-width: 60ch;
  font-size: 16px;
  line-height: 1.75;
  color: var(--body);
}

/* ---------- 区域小组 ---------- */
.page-about .about-teams__head {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(22px, 3vw, 44px);
  align-items: flex-end;
  justify-content: space-between;
}

.page-about .about-focus {
  flex: 0 0 auto;
  width: 100%;
  max-width: 300px;
}

.page-about .about-focus .data-card__value {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(48px, 7vw, 66px);
  line-height: 1;
  color: var(--gold-light);
}

.page-about .about-focus .data-card__unit {
  font-family: var(--font-body);
  font-size: 16px;
  margin-left: 6px;
  color: var(--body-dim);
}

.page-about .about-region__figure {
  margin: clamp(28px, 4vw, 44px) 0 0;
  border: var(--about-rule);
  background: var(--graphite);
}

.page-about .about-region__figure .media-frame__inner {
  aspect-ratio: 7 / 4;
  overflow: hidden;
}

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

.page-about .about-nodes {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: clamp(24px, 3vw, 34px);
}

.page-about .about-node {
  background: var(--graphite);
  border: var(--about-rule);
  box-shadow: inset 0 0 0 1px var(--foil-line);
}

.page-about .about-node--hub {
  border-color: var(--line-strong);
}

.page-about .about-node__sum {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 18px;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  color: var(--paper);
  transition: color 0.3s var(--ease);
}

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

.page-about .about-node__sum::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 17px;
  color: var(--gold);
  transition: transform 0.3s var(--ease);
}

.page-about .about-node[open] .about-node__sum::after {
  content: "–";
}

.page-about .about-node__sum:hover,
.page-about .about-node__sum:focus-visible {
  color: var(--gold-light);
}

.page-about .about-node__sum:focus-visible {
  outline: 2px solid var(--teal);
  outline-offset: -2px;
}

.page-about .about-node__dot {
  flex: 0 0 9px;
  width: 9px;
  height: 9px;
  border: 1px solid var(--gold);
  transform: rotate(45deg);
}

.page-about .about-node--hub .about-node__dot {
  background: var(--gold);
  box-shadow: 0 0 0 3px rgba(201, 162, 75, 0.18);
}

.page-about .about-node__body {
  padding: 0 18px 20px;
  border-top: var(--about-rule);
  padding-top: 16px;
}

.page-about .about-node__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--body);
}

/* ---------- 公开信息 ---------- */
.page-about .about-facts {
  margin: clamp(26px, 4vw, 40px) 0 0;
  border-top: var(--about-rule);
}

.page-about .about-facts__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 18px 0;
  border-bottom: var(--about-rule);
}

.page-about .about-facts__row dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--gold-light);
}

.page-about .about-facts__row dd {
  margin: 0;
  font-size: 16px;
  line-height: 1.72;
  color: var(--body);
}

.page-about .about-facts__mono {
  font-family: var(--font-mono);
  letter-spacing: 0.04em;
  color: var(--paper);
}

/* ---------- 结尾 ---------- */
.page-about .about-sec--visit {
  border-top: var(--about-rule);
}

.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: clamp(28px, 4vw, 40px);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-cities {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }

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

  .page-about .about-facts__row {
    grid-template-columns: 160px minmax(0, 1fr);
    gap: 28px;
    align-items: baseline;
  }

  .page-about .about-principle {
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 10px 32px;
    align-items: start;
  }

  .page-about .about-principle__no {
    padding-top: 7px;
  }

  .page-about .about-principle__name {
    grid-column: 2;
  }

  .page-about .about-principle__text {
    grid-column: 2;
  }

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

  .page-about .about-focus {
    width: auto;
  }
}

@media (min-width: 1000px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: clamp(40px, 5vw, 88px);
  }

  .page-about .about-body__layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(48px, 6vw, 112px);
  }

  .page-about .about-rail {
    display: block;
    position: sticky;
    top: calc(var(--header-h) + 36px);
    align-self: start;
    padding-right: 12px;
    border-right: var(--about-rule);
  }

  .page-about .about-phases {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
    align-items: start;
    gap: clamp(28px, 3vw, 48px);
  }

  .page-about .about-track {
    padding-top: 0;
  }
}

@media (min-width: 1180px) {
  .page-about .about-nodes {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-node__sum {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    padding: 22px 18px 18px;
  }

  .page-about .about-node__sum::after {
    position: absolute;
    top: 16px;
    right: 16px;
  }

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