.page-about {
  --ab-index-col: 92px;
  background: var(--paper);
  color: var(--ink);
  padding-bottom: clamp(40px, 6vw, 88px);
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about section[id] {
  scroll-margin-top: 84px;
}

.page-about img {
  max-width: 100%;
  height: auto;
}

/* ---------- 面包屑 ---------- */

.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-top: clamp(20px, 3vw, 34px);
  font-size: 13px;
  color: var(--concrete);
}

.page-about .breadcrumb a {
  color: var(--concrete);
  text-decoration: none;
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--copper);
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(30px, 5vw, 52px);
  padding-top: clamp(30px, 4.5vw, 52px);
  padding-bottom: clamp(44px, 6vw, 84px);
}

.page-about .ab-hero__toc-title {
  margin: 0 0 14px;
  color: var(--concrete);
}

.page-about .ab-toc {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 18px;
}

.page-about .ab-toc a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 11px 0;
  border-bottom: 1px solid var(--grid);
  color: var(--ink);
  text-decoration: none;
  font-size: 14px;
  line-height: 1.5;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .ab-toc a:hover,
.page-about .ab-toc a:focus-visible {
  color: var(--copper);
  border-color: var(--copper);
}

.page-about .ab-toc .num {
  font-size: 12px;
  letter-spacing: .05em;
  color: var(--copper);
  flex: none;
}

.page-about .ab-hero__lead .eyebrow {
  margin: 0 0 16px;
  color: var(--copper);
}

.page-about .ab-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(32px, 6vw, 64px);
  line-height: 1.14;
  letter-spacing: -0.01em;
  margin: 0 0 22px;
  max-width: 17em;
}

.page-about .ab-hero .lede {
  font-size: clamp(16px, 1.6vw, 18px);
  line-height: 1.9;
  color: var(--ink-80);
  max-width: 44em;
  margin: 0 0 28px;
}

.page-about .ab-hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 章节骨架 ---------- */

.page-about .ab-chapter {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(18px, 3vw, 28px);
  padding-top: clamp(42px, 6vw, 82px);
}

.page-about .ab-chapter__index {
  display: flex;
  align-items: center;
  gap: 14px;
  color: var(--copper);
}

.page-about .ab-chapter__index .num {
  font-size: 24px;
  line-height: 1;
  letter-spacing: .06em;
}

.page-about .ab-chapter__line {
  flex: 1 1 auto;
  height: 1px;
  min-width: 40px;
  background: var(--grid);
}

.page-about .ab-chapter__title {
  font-family: var(--font-display);
  font-size: clamp(25px, 3.4vw, 40px);
  line-height: 1.26;
  letter-spacing: -0.005em;
  margin: 0 0 18px;
}

.page-about .ab-chapter__intro {
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink-80);
  max-width: 46em;
  margin: 0 0 clamp(26px, 4vw, 42px);
}

.page-about .ab-chapter__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 4vw, 40px);
}

.page-about .ab-chapter__text p {
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink-80);
  margin: 0 0 18px;
  max-width: 40em;
}

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

.page-about .ab-chapter__figure,
.page-about .ab-wide,
.page-about .ab-partners__figure {
  margin: 0;
}

.page-about .ab-chapter__figure img,
.page-about .ab-wide img,
.page-about .ab-partners__figure img {
  display: block;
  width: 100%;
  object-fit: cover;
  border: 1px solid var(--grid);
  background: var(--grid);
}

.page-about .ab-chapter__figure img {
  aspect-ratio: 4 / 3;
}

.page-about .ab-wide {
  margin-top: clamp(30px, 5vw, 54px);
}

.page-about .ab-wide img {
  aspect-ratio: 2 / 1;
}

.page-about .ab-partners__figure img {
  aspect-ratio: 3 / 2;
}

.page-about .media__caption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--concrete);
}

/* ---------- 版本时间轴 ---------- */

.page-about .ab-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .ab-stage {
  position: relative;
}

.page-about .ab-node {
  border: 1px solid var(--grid);
  background: rgba(255, 255, 255, .45);
  transition: border-color .22s var(--ease);
}

.page-about .ab-node[open] {
  border-color: var(--copper);
}

.page-about .ab-node__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 18px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .ab-node__head::after {
  content: "+";
  font-family: var(--font-data);
  font-size: 17px;
  line-height: 1;
  color: var(--copper);
  flex: none;
  align-self: center;
}

.page-about .ab-node[open] .ab-node__head::after {
  content: "−";
}

.page-about .ab-node__year {
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--copper);
  flex: none;
}

.page-about .ab-node__name {
  font-family: var(--font-display);
  font-size: 17px;
  line-height: 1.5;
  flex: 1 1 auto;
}

.page-about .ab-node__body {
  padding: 0 18px 20px;
}

.page-about .ab-node__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-80);
}

/* ---------- 团队 ---------- */

.page-about .ab-team {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .ab-team__card {
  background: var(--paper);
  padding: clamp(22px, 3vw, 30px);
}

.page-about .ab-team__tag {
  display: inline-block;
  margin-bottom: 14px;
}

.page-about .ab-team__card h3 {
  font-family: var(--font-display);
  font-size: 19px;
  line-height: 1.45;
  margin: 0 0 12px;
}

.page-about .ab-team__card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-80);
}

/* ---------- 数据规模（深色） ---------- */

.page-about .ab-scale {
  margin-top: clamp(48px, 7vw, 96px);
  background: var(--ink);
  color: var(--paper);
  padding: clamp(44px, 6.5vw, 92px) 0;
}

.page-about .ab-scale__head {
  max-width: 46em;
  margin-bottom: clamp(30px, 4.6vw, 52px);
}

.page-about .ab-scale__num {
  display: block;
  font-size: 22px;
  letter-spacing: .06em;
  color: var(--copper-lit);
  margin-bottom: 16px;
}

.page-about .ab-chapter__title--ink {
  color: var(--paper);
  margin-bottom: 16px;
}

.page-about .ab-scale__head p {
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(244, 239, 230, .78);
  max-width: 42em;
}

.page-about .ab-scale__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0 0 clamp(28px, 4vw, 44px);
  background: rgba(201, 194, 182, .26);
  border: 1px solid rgba(201, 194, 182, .26);
}

.page-about .ab-scale__item {
  background: var(--ink);
  padding: clamp(18px, 2.6vw, 28px);
}

.page-about .ab-scale__item dt {
  font-size: 13px;
  line-height: 1.6;
  color: rgba(244, 239, 230, .62);
  margin-bottom: 10px;
}

.page-about .ab-scale__item dd {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: 4px;
  font-size: 14px;
  color: rgba(244, 239, 230, .9);
}

.page-about .ab-scale__value {
  font-size: clamp(24px, 3.2vw, 34px);
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .ab-scale__note {
  margin: 0;
  font-size: 15px;
  line-height: 1.9;
  color: rgba(244, 239, 230, .74);
  max-width: 52em;
}

/* ---------- 合作生态 ---------- */

.page-about .ab-partners {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 52px);
}

.page-about .ab-partners__list {
  list-style: none;
  margin: 0 0 clamp(28px, 4vw, 40px);
  padding: 0;
}

.page-about .ab-partners__list li {
  position: relative;
  padding: 16px 0 16px 22px;
  border-top: 1px solid var(--grid);
}

.page-about .ab-partners__list li:last-child {
  border-bottom: 1px solid var(--grid);
}

.page-about .ab-partners__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 27px;
  width: 9px;
  height: 1px;
  background: var(--copper);
}

.page-about .ab-partners__list h3 {
  margin: 0 0 6px;
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 700;
  line-height: 1.5;
}

.page-about .ab-partners__list p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-80);
}

.page-about .ab-awards {
  border-left: 2px solid var(--pickle);
  padding-left: 18px;
}

.page-about .ab-awards__label {
  margin: 0 0 10px;
  font-family: var(--font-body);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--concrete);
}

.page-about .ab-awards ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-awards li {
  display: flex;
  align-items: baseline;
  gap: 12px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-80);
}

.page-about .ab-awards li .num {
  flex: none;
  font-size: 13px;
  color: var(--copper);
}

/* ---------- 服务节奏 ---------- */

.page-about .ab-cadence {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--grid);
  border: 1px solid var(--grid);
}

.page-about .ab-cadence__item {
  background: var(--paper);
  padding: clamp(22px, 3vw, 30px);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.page-about .ab-cadence__item .tag {
  align-self: flex-start;
}

.page-about .ab-cadence__item h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 19px;
  line-height: 1.4;
}

.page-about .ab-cadence__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-80);
}

/* ---------- 行动区 ---------- */

.page-about .ab-cta {
  margin-top: clamp(48px, 7vw, 96px);
  background: var(--copper);
  color: var(--paper);
}

.page-about .ab-cta__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(18px, 3vw, 26px);
  padding: clamp(42px, 6vw, 78px) 0;
}

.page-about .ab-cta__title {
  font-family: var(--font-display);
  font-size: clamp(24px, 3.2vw, 36px);
  line-height: 1.3;
  margin: 0;
  color: var(--white);
}

.page-about .ab-cta__text {
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(244, 239, 230, .88);
  max-width: 40em;
}

.page-about .ab-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 760px) {
  .page-about .ab-team {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

@media (min-width: 860px) {
  .page-about .ab-hero {
    grid-template-columns: minmax(190px, 228px) minmax(0, 1fr);
    gap: clamp(40px, 5.5vw, 84px);
    align-items: start;
  }

  .page-about .ab-toc {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .page-about .ab-chapter {
    grid-template-columns: var(--ab-index-col) minmax(0, 1fr);
    gap: 0 clamp(32px, 5vw, 68px);
  }

  .page-about .ab-chapter__index {
    flex-direction: column;
    align-items: flex-start;
    gap: 20px;
  }

  .page-about .ab-chapter__line {
    flex: none;
    width: 1px;
    min-width: 0;
    height: clamp(64px, 11vw, 132px);
    background: linear-gradient(to bottom, var(--copper), rgba(47, 111, 99, 0));
  }

  .page-about .ab-chapter__grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 1fr);
    gap: clamp(32px, 5vw, 62px);
    align-items: start;
  }

  .page-about .ab-partners {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .ab-cta__inner {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 1fr);
    align-items: start;
    column-gap: clamp(40px, 6vw, 88px);
    row-gap: 22px;
  }

  .page-about .ab-cta__title {
    grid-column: 1;
    grid-row: 1 / span 2;
    align-self: center;
  }

  .page-about .ab-cta__text {
    grid-column: 2;
    grid-row: 1;
  }

  .page-about .ab-cta__links {
    grid-column: 2;
    grid-row: 2;
  }
}

@media (min-width: 1080px) {
  .page-about .ab-timeline {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0 26px;
    align-items: start;
  }

  .page-about .ab-stage {
    border-top: 1px solid var(--grid);
    padding-top: 28px;
  }

  .page-about .ab-stage::before {
    content: "";
    position: absolute;
    top: -4px;
    left: 0;
    width: 7px;
    height: 7px;
    background: var(--copper);
  }

  .page-about .ab-stage.is-key::before {
    background: var(--hibiscus);
  }

  .page-about .ab-node {
    border: 0;
    background: transparent;
  }

  .page-about .ab-node__head {
    display: block;
    position: relative;
    padding: 0 26px 12px 0;
  }

  .page-about .ab-node__year {
    display: block;
    font-size: 21px;
    margin-bottom: 10px;
  }

  .page-about .ab-node__name {
    display: block;
    font-size: 17px;
    line-height: 1.45;
  }

  .page-about .ab-node__head::after {
    position: absolute;
    right: 0;
    top: 2px;
    align-self: auto;
  }

  .page-about .ab-node__body {
    padding: 0 26px 0 0;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}