.page-about {
  --about-rule: rgba(140, 147, 168, 0.32);
  --about-rule-strong: rgba(140, 147, 168, 0.6);
  --about-rail-w: 176px;
  padding-bottom: clamp(48px, 8vw, 96px);
}

.page-about .about-intro {
  padding-top: clamp(28px, 6vw, 56px);
}

.page-about .about-intro__grid {
  display: grid;
  gap: clamp(28px, 5vw, 48px);
  margin-top: clamp(20px, 4vw, 36px);
}

.page-about .about-intro__lead .h1 {
  margin: 10px 0 18px;
  max-width: 20em;
}

.page-about .about-intro__panel {
  background: var(--cream);
  color: var(--soot);
  padding: clamp(20px, 4vw, 30px) clamp(18px, 3.4vw, 28px);
  clip-path: var(--cut-panel);
}

.page-about .about-intro__panelhead {
  font-size: var(--t-12);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--crimson);
  margin: 0 0 16px;
  font-weight: 700;
}

.page-about .about-keyfacts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-keyfacts li {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(32, 22, 15, 0.14);
}

.page-about .about-keyfacts li:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-keyfacts__num {
  font-size: var(--t-24);
  font-weight: 700;
  color: var(--soot);
  min-width: 3.2em;
}

.page-about .about-keyfacts__label {
  font-size: var(--t-14);
  color: rgba(32, 22, 15, 0.72);
}

.page-about .about-intro__note {
  margin: 18px 0 0;
  font-size: var(--t-12);
  line-height: 1.7;
  color: rgba(32, 22, 15, 0.6);
}

/* 编辑式左右架构 */
.page-about .about-frame {
  display: grid;
  gap: clamp(24px, 4vw, 48px);
  width: var(--wrap);
  margin: clamp(40px, 7vw, 76px) auto 0;
}

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

.page-about .about-rail__list {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
}

.page-about .about-rail__list .indexnav__link {
  font-size: var(--t-14);
  color: var(--stone);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color 200ms var(--ease), border-color 200ms var(--ease);
}

.page-about .about-rail__list .indexnav__link:hover,
.page-about .about-rail__list .indexnav__link:focus-visible {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

.page-about .about-rail__list .indexnav__link[aria-current="true"] {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

.page-about .about-rail__scale {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 14px;
  border-top: 1px solid var(--about-rule);
  padding-top: 10px;
}

.page-about .about-rail__tick {
  width: 14px;
  height: 2px;
  background: var(--about-rule-strong);
}

.page-about .about-rail__tick.is-on {
  background: var(--jade);
  width: 26px;
}

.page-about .about-block {
  padding-top: clamp(34px, 6vw, 60px);
  border-top: 1px solid var(--about-rule);
}

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

.page-about .about-block + .about-block {
  margin-top: clamp(34px, 6vw, 64px);
}

.page-about .about-block .h2 {
  margin: 10px 0 16px;
  max-width: 22em;
}

.page-about .about-lede {
  color: var(--stone);
  max-width: 46ch;
}

.page-about .about-cols {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
  margin-top: 24px;
}

.page-about .about-cols p {
  margin: 0 0 14px;
}

.page-about .about-cols .list {
  margin-top: 8px;
}

.page-about .about-tail {
  margin-top: 26px;
  padding-top: 16px;
  border-top: 1px solid var(--about-rule);
  font-size: var(--t-14);
  color: var(--stone);
}

/* 阶段带 */
.page-about .about-band {
  margin: 24px 0 8px;
}

.page-about .about-band img {
  border-radius: 0;
  clip-path: var(--cut-panel);
}

.page-about .stage-list {
  list-style: none;
  margin: 32px 0 0;
  padding: 0;
}

.page-about .stage {
  position: relative;
  display: grid;
  gap: 12px;
  padding: 0 0 28px 20px;
  border-left: 1px solid var(--about-rule);
}

.page-about .stage:last-child {
  border-left-color: transparent;
  padding-bottom: 0;
}

.page-about .stage::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 6px;
  width: 7px;
  height: 7px;
  background: var(--jade);
}

.page-about .stage:nth-child(2)::before { background: var(--gold); }
.page-about .stage:nth-child(3)::before { background: var(--green); }
.page-about .stage:nth-child(4)::before { background: var(--crimson); }

.page-about .stage__mark {
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.page-about .stage__idx {
  font-size: var(--t-12);
  letter-spacing: 0.16em;
  color: var(--stone);
}

.page-about .stage__year {
  font-size: var(--t-14);
  color: var(--gold);
  font-weight: 700;
}

.page-about .stage__body .h3 {
  margin: 0 0 8px;
}

.page-about .stage__body p {
  margin: 0 0 10px;
}

.page-about .stage__note {
  font-size: var(--t-14);
  color: var(--stone);
  padding-left: 14px;
  border-left: 2px solid var(--jade);
}

/* 六类 */
.page-about .scope-flow {
  display: none;
}

.page-about .scope-list {
  margin-top: 24px;
  border-top: 1px solid var(--about-rule);
}

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

.page-about .scope-list .expander__btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 4px;
  background: transparent;
  border: 0;
  color: var(--cream);
  text-align: left;
  cursor: pointer;
  transition: color 200ms var(--ease);
}

.page-about .scope-list .expander__btn:hover,
.page-about .scope-list .expander__btn:focus-visible {
  color: var(--gold);
}

.page-about .scope-item__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 16px;
}

.page-about .scope-item__idx {
  font-size: var(--t-12);
  letter-spacing: 0.1em;
  color: var(--stone);
  min-width: 4.4em;
}

.page-about .scope-item__name {
  font-size: var(--t-19);
  font-weight: 700;
}

.page-about .scope-item__stage {
  font-size: var(--t-12);
  letter-spacing: 0.08em;
  color: var(--jade);
  border: 1px solid rgba(42, 166, 162, 0.5);
  padding: 2px 8px;
}

.page-about .scope-list .expander__body p {
  margin: 0 0 10px;
}

.page-about .scope-list .expander__body p:last-child {
  margin-bottom: 0;
}

/* 团队 */
.page-about .team-wrap {
  display: grid;
  gap: clamp(24px, 4vw, 40px);
  margin-top: 26px;
}

.page-about .team-mapbox {
  background: var(--ink-2);
  padding: clamp(14px, 3vw, 26px);
  clip-path: var(--cut-panel);
}

.page-about .team-map {
  display: block;
  width: 100%;
  height: auto;
  max-width: 560px;
  margin: 0 auto;
}

.page-about .team-map__edges path {
  fill: none;
  stroke: rgba(140, 147, 168, 0.45);
  stroke-width: 1.5;
  stroke-dasharray: 5 5;
}

.page-about .team-map__node circle {
  fill: var(--ink);
  stroke: var(--cream);
  stroke-width: 1.5;
  transition: fill 200ms var(--ease), stroke 200ms var(--ease);
}

.page-about .team-map__node text {
  fill: var(--cream);
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 700;
  text-anchor: middle;
  dominant-baseline: middle;
}

.page-about .team-map__node--a circle { stroke: var(--jade); }
.page-about .team-map__node--b circle { stroke: var(--gold); }
.page-about .team-map__node--c circle { stroke: var(--green); }
.page-about .team-map__node--d circle { stroke: var(--crimson); }

.page-about .team-map__node:hover circle {
  fill: var(--gold);
  stroke: var(--gold);
}

.page-about .team-map__node:hover text {
  fill: var(--soot);
}

.page-about .team-media img {
  clip-path: var(--cut-panel);
}

.page-about .team-roles {
  margin: 32px 0 0;
  display: grid;
  gap: 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .team-role {
  display: grid;
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .team-role dt {
  font-size: var(--t-19);
  font-weight: 700;
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.page-about .team-role__n {
  font-size: var(--t-12);
  color: var(--gold);
  letter-spacing: 0.16em;
}

.page-about .team-role dd {
  margin: 0;
  font-size: var(--t-16);
  color: var(--stone);
  line-height: 1.75;
}

/* 维护 */
.page-about .upkeep-grid {
  display: grid;
  gap: clamp(24px, 4vw, 40px);
  margin-top: 26px;
}

.page-about .upkeep-cycle {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 22px;
}

.page-about .upkeep-cycle li {
  padding-left: 16px;
  border-left: 2px solid var(--gold);
}

.page-about .upkeep-cycle__k {
  display: inline-block;
  font-size: var(--t-12);
  letter-spacing: 0.14em;
  color: var(--gold);
  margin-bottom: 8px;
}

.page-about .upkeep-cycle p {
  margin: 0;
}

.page-about .upkeep-media img {
  clip-path: var(--cut-panel);
}

/* 协作与自查 */
.page-about .section--cream .h2 {
  color: var(--soot);
}

.page-about .section--cream .eyebrow {
  color: var(--crimson);
}

.page-about .eco-grid {
  display: grid;
  gap: 0;
  margin-top: 24px;
  border-top: 1px solid rgba(32, 22, 15, 0.18);
}

.page-about .eco-cell {
  padding: 20px 0;
  border-bottom: 1px solid rgba(32, 22, 15, 0.18);
}

.page-about .eco-cell__num {
  font-size: var(--t-44);
  font-weight: 700;
  color: var(--crimson);
  line-height: 1;
  margin: 0 0 10px;
}

.page-about .eco-cell__label {
  margin: 0 0 6px;
  font-size: var(--t-16);
  font-weight: 700;
  color: var(--soot);
}

.page-about .eco-cell__note {
  margin: 0;
  font-size: var(--t-14);
  line-height: 1.7;
  color: rgba(32, 22, 15, 0.68);
}

.page-about .eco-foot {
  margin: 26px 0 0;
  font-size: var(--t-14);
  line-height: 1.8;
  color: rgba(32, 22, 15, 0.78);
}

.page-about .section--cream .link-u {
  color: var(--crimson);
  border-bottom-color: rgba(183, 54, 42, 0.5);
}

/* 窄屏到宽屏 */
@media (min-width: 620px) {
  .page-about .about-cols {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .eco-grid {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .eco-cell {
    padding: 22px 20px;
    border-right: 1px solid rgba(32, 22, 15, 0.18);
  }

  .page-about .eco-cell:nth-child(2n) {
    border-right: 0;
  }

  .page-about .team-role {
    grid-template-columns: 190px 1fr;
    gap: 20px;
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .about-intro__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }

  .page-about .about-frame {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 118px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 10px;
  }

  .page-about .about-rail__scale {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    margin-top: 20px;
  }

  .page-about .about-rail__tick {
    width: 18px;
    transition: width 220ms var(--ease), background-color 220ms var(--ease);
  }

  .page-about .about-rail__tick.is-on {
    width: 40px;
  }

  .page-about .stage {
    grid-template-columns: 140px minmax(0, 1fr);
    gap: 28px;
    padding-left: 28px;
  }

  .page-about .stage__mark {
    flex-direction: column;
    gap: 6px;
  }

  .page-about .scope-flow {
    display: flex;
    align-items: center;
    gap: 0;
    margin: 22px 0 4px;
  }

  .page-about .scope-flow__line {
    flex: 1 1 auto;
    height: 1px;
    background: linear-gradient(90deg, var(--jade), var(--gold));
    opacity: 0.55;
  }

  .page-about .scope-flow__dot {
    width: 8px;
    height: 8px;
    background: var(--gold);
    flex: 0 0 auto;
  }

  .page-about .scope-flow .scope-flow__dot:first-child {
    background: var(--jade);
  }

  .page-about .team-wrap {
    grid-template-columns: minmax(0, 1fr) minmax(0, 320px);
    align-items: stretch;
  }

  .page-about .upkeep-grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    align-items: start;
  }

  .page-about .eco-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .page-about .eco-cell {
    border-right: 1px solid rgba(32, 22, 15, 0.18);
  }

  .page-about .eco-cell:nth-child(2n) {
    border-right: 1px solid rgba(32, 22, 15, 0.18);
  }

  .page-about .eco-cell:last-child {
    border-right: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__tick,
  .page-about .team-map__node circle,
  .page-about .scope-list .expander__btn {
    transition: none;
  }
}