.page-about {
  --about-rule: rgba(110, 106, 98, .3);
  --about-line: rgba(15, 59, 58, .22);
  --about-rail: 66px;
  background: var(--c-sand);
  color: var(--c-ink);
  padding-bottom: clamp(40px, 8vw, 96px);
  overflow-x: clip;
}

/* ---------- 页面路径 ---------- */
.page-about .breadcrumb {
  padding-top: clamp(14px, 3vw, 22px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
}

.page-about .breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  color: var(--c-rock);
}

.page-about .breadcrumb__item {
  display: inline-flex;
  align-items: center;
}

.page-about .breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  margin-right: 8px;
  color: var(--c-rock);
  opacity: .6;
}

.page-about .breadcrumb__item a {
  color: var(--c-cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--about-rule);
  transition: border-color 160ms var(--ease);
}

.page-about .breadcrumb__item a:hover,
.page-about .breadcrumb__item a:focus-visible {
  border-bottom-color: var(--c-whistle);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: clamp(26px, 6vw, 64px) 0 clamp(18px, 4vw, 38px);
}

.page-about .about-hero__coord {
  margin: 0 0 clamp(14px, 3vw, 26px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--c-rock);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(20px, 4vw, 36px);
}

.page-about .about-hero__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(38px, 6vw, 80px);
  line-height: 1.02;
  letter-spacing: -.02em;
  color: var(--c-cyan);
  max-width: 14em;
}

.page-about .about-hero__lede {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--c-ink);
  max-width: 34em;
}

.page-about .about-facts {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(14px, 3vw, 32px);
  margin: clamp(18px, 3vw, 26px) 0 0;
  padding: clamp(14px, 2vw, 18px) 0 0;
  list-style: none;
  border-top: 1px solid var(--about-line);
}

.page-about .about-facts li {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.page-about .about-facts__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(22px, 3vw, 30px);
  line-height: 1;
  color: var(--c-cyan);
}

.page-about .about-facts__label {
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--c-rock);
}

/* ---------- 轨道与坐标栏 ---------- */
.page-about .about-track {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0 clamp(16px, 3vw, 40px);
  align-items: start;
}

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

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

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  padding: clamp(26px, 5vw, 54px) 0;
}

.page-about .about-sec__head {
  max-width: 34em;
}

.page-about .about-sec h2 {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(25px, 4vw, 40px);
  line-height: 1.14;
  letter-spacing: -.015em;
  color: var(--c-cyan);
}

.page-about .about-sec__lede {
  margin: clamp(14px, 2vw, 20px) 0 0;
}

.page-about .prose p {
  margin: 0 0 1em;
  font-size: 16px;
  line-height: 1.78;
  max-width: 32em;
}

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

.page-about .about-drop::first-letter {
  float: left;
  margin: 5px 9px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 52px;
  line-height: .88;
  color: var(--c-cyan);
}

/* ---------- 两栏图文 ---------- */
.page-about .about-two {
  display: grid;
  gap: clamp(20px, 4vw, 38px);
  margin-top: clamp(18px, 4vw, 32px);
}

.page-about .about-two__fig img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  filter: saturate(.92) contrast(1.03);
}

.page-about .about-cap {
  display: block;
  margin-top: 10px;
  padding-left: 12px;
  border-left: 2px solid var(--c-whistle);
  font-size: 13px;
  line-height: 1.65;
  color: var(--c-rock);
}

/* ---------- 编年 ---------- */
.page-about .about-chrono__band {
  position: relative;
  margin-bottom: clamp(18px, 3vw, 30px);
  overflow: hidden;
}

.page-about .about-chrono__band img {
  display: block;
  width: 100%;
  height: clamp(120px, 20vw, 210px);
  object-fit: cover;
}

.page-about .about-chrono__band::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(96deg, rgba(8, 39, 38, .84) 0%, rgba(15, 59, 58, .42) 52%, rgba(180, 98, 58, .58) 100%);
}

.page-about .about-chrono__stamp {
  position: absolute;
  right: clamp(12px, 2vw, 24px);
  bottom: clamp(10px, 1.6vw, 18px);
  z-index: 1;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--c-sand);
}

.page-about .chrono {
  margin: clamp(18px, 3vw, 30px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .chrono__item {
  position: relative;
  margin-left: 7px;
  padding: 0 0 clamp(18px, 3vw, 28px) clamp(18px, 3vw, 30px);
  border-left: 2px solid rgba(15, 59, 58, .32);
}

.page-about .chrono__item:last-child {
  padding-bottom: 0;
  border-left-style: dashed;
  border-left-color: var(--c-whistle);
}

.page-about .chrono__item::before {
  content: "";
  position: absolute;
  left: -8px;
  top: 5px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--c-whistle);
  box-shadow: 0 0 0 2px var(--c-sand), 0 0 0 3px rgba(15, 59, 58, .3);
}

.page-about .chrono__item--live::before {
  box-shadow: 0 0 0 2px var(--c-sand), 0 0 0 3px var(--c-whistle), 0 0 0 7px rgba(233, 178, 31, .22);
}

.page-about .chrono__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0 0 6px;
}

.page-about .chrono__year {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--c-rock);
}

.page-about .chrono__title {
  margin: 0 0 5px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(17px, 2.3vw, 21px);
  letter-spacing: -.01em;
  color: var(--c-ink);
}

.page-about .chrono__desc {
  margin: 0;
  max-width: 34em;
  font-size: 15px;
  line-height: 1.72;
  color: var(--c-rock);
}

/* ---------- 斜切分隔带 ---------- */
.page-about .about-slash {
  height: clamp(30px, 5vw, 54px);
  margin: clamp(16px, 3vw, 30px) 0;
  background: repeating-linear-gradient(115deg, var(--c-clay) 0 10px, var(--c-whistle) 10px 14px, transparent 14px 27px);
  clip-path: polygon(0 32%, 100% 0, 100% 68%, 0 100%);
  opacity: .9;
}

/* ---------- 团队分工 ---------- */
.page-about .duties {
  margin-top: clamp(18px, 3vw, 28px);
  border-top: 1px solid var(--about-rule);
}

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

.page-about .duty__head {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr) auto 22px;
  align-items: center;
  gap: 10px;
  padding: clamp(13px, 2vw, 18px) 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .duty__head:focus-visible {
  outline: 2px solid var(--c-whistle);
  outline-offset: 4px;
}

.page-about .duty__no {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .12em;
  color: var(--c-rock);
}

.page-about .duty__name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(17px, 2.3vw, 22px);
  letter-spacing: -.01em;
  color: var(--c-cyan);
}

.page-about .duty__size {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--c-moss);
}

.page-about .duty__head::after {
  content: "＋";
  justify-self: end;
  font-size: 15px;
  line-height: 1;
  color: var(--c-whistle);
}

.page-about .duty[open] .duty__head::after {
  content: "−";
}

.page-about .duty__body {
  padding: 0 clamp(0px, 2vw, 24px) clamp(14px, 2vw, 20px) 50px;
}

.page-about .duty__body p {
  margin: 0;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.75;
  color: var(--c-rock);
}

/* ---------- 五步流程 ---------- */
.page-about .about-flow {
  margin-top: clamp(18px, 3vw, 30px);
}

/* ---------- 覆盖版图 ---------- */
.page-about .atlas {
  display: grid;
  gap: clamp(18px, 3vw, 34px);
  margin-top: clamp(18px, 3vw, 30px);
  align-items: start;
}

.page-about .atlas__map {
  position: relative;
  aspect-ratio: 7 / 6;
  width: 100%;
  max-width: 420px;
  background-color: rgba(15, 59, 58, .07);
  background-image: radial-gradient(circle at center, var(--c-cyan) 3.1px, transparent 3.7px);
  background-size: calc(100% / 7) calc(100% / 6);
  border: 1px solid var(--about-rule);
}

.page-about .atlas__stamp {
  position: absolute;
  right: 10px;
  bottom: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--c-clay);
}

.page-about .atlas__list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--about-rule);
}

.page-about .atlas__item {
  display: grid;
  grid-template-columns: minmax(72px, auto) minmax(0, 1fr) 34px;
  align-items: center;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .atlas__city {
  font-size: 15px;
  color: var(--c-ink);
}

.page-about .atlas__bar {
  display: block;
  height: 6px;
  background: rgba(110, 106, 98, .18);
}

.page-about .atlas__bar i {
  display: block;
  height: 100%;
  background: var(--c-cyan);
}

.page-about .atlas__count {
  font-family: var(--font-mono);
  font-size: 14px;
  text-align: right;
  color: var(--c-cyan);
}

/* ---------- 三列坐标卡 ---------- */
.page-about .about-cards {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: clamp(22px, 4vw, 40px);
  background: var(--about-rule);
  border: 1px solid var(--about-rule);
}

.page-about .about-card {
  padding: clamp(16px, 3vw, 24px);
  background: var(--c-sand);
  border-left: 3px solid var(--c-whistle);
}

.page-about .about-card__axis {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--c-rock);
}

.page-about .about-card__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  letter-spacing: .02em;
  color: var(--c-moss);
}

.page-about .about-card__num {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(21px, 3vw, 27px);
  line-height: 1.15;
  color: var(--c-cyan);
}

.page-about .about-card__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--c-rock);
}

/* ---------- 后续入口 ---------- */
.page-about .about-next__list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: clamp(18px, 3vw, 28px) 0 0;
  padding: 0;
  list-style: none;
  background: var(--about-rule);
  border-top: 1px solid var(--about-rule);
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-next__item {
  display: flex;
  flex-direction: column;
  gap: 7px;
  padding: clamp(14px, 2.6vw, 20px) clamp(12px, 2vw, 20px);
  background: var(--c-sand);
}

.page-about .about-next__item a {
  align-self: flex-start;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  color: var(--c-cyan);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: border-color 160ms var(--ease), color 160ms var(--ease);
}

.page-about .about-next__item a:hover,
.page-about .about-next__item a:focus-visible {
  border-bottom-color: var(--c-whistle);
  color: var(--c-night);
}

.page-about .about-next__note {
  font-size: 14px;
  line-height: 1.68;
  color: var(--c-rock);
  max-width: 30em;
}

/* ---------- 中等屏幕 ---------- */
@media (min-width: 760px) {
  .page-about .atlas {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  }

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

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

/* ---------- 桌面：坐标栏 + 图文错位 ---------- */
@media (min-width: 900px) {
  .page-about .about-track {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
  }

  .page-about .about-rail {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 12px;
    position: sticky;
    top: 108px;
    padding-right: 14px;
    border-right: 1px solid var(--about-rule);
  }

  .page-about .about-rail__mark {
    margin: 0;
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 15px;
    letter-spacing: .16em;
    color: var(--c-clay);
    writing-mode: vertical-rl;
  }

  .page-about .about-rail__rule {
    display: block;
    width: 1px;
    height: clamp(60px, 10vw, 120px);
    background: repeating-linear-gradient(180deg, var(--c-rock) 0 5px, transparent 5px 10px);
    opacity: .7;
  }

  .page-about .about-rail__text {
    margin: 0;
    font-size: 12px;
    letter-spacing: .3em;
    color: var(--c-rock);
    writing-mode: vertical-rl;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, .95fr);
    align-items: end;
    gap: clamp(30px, 5vw, 76px);
  }

  .page-about .about-two {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
    gap: clamp(26px, 4vw, 52px);
  }

  .page-about .about-two--flip .about-two__fig {
    order: 1;
  }

  .page-about .about-two--flip .about-two__text {
    order: 2;
  }

  .page-about .about-hero,
  .page-about .about-sec {
    padding-left: clamp(4px, 1vw, 14px);
  }
}