.page-about {
  --about-hair: rgba(58, 62, 68, 0.92);
  --about-ruler: rgba(201, 164, 92, 0.24);
  --about-block: clamp(52px, 8vw, 104px);
  background: var(--ink);
  color: var(--paper);
  overflow-x: hidden;
}

.page-about .about-crumbs {
  padding-top: clamp(20px, 3vw, 34px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--graygold);
}

.page-about .about-crumbs .breadcrumb__link {
  color: var(--coolgray);
  text-decoration: none;
}

.page-about .about-crumbs .breadcrumb__link:hover {
  color: var(--gold-light);
}

/* 首屏：目录式开场 */
.page-about .about-intro {
  padding: clamp(28px, 4vw, 46px) 0 var(--about-block);
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-intro__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 56px);
  align-items: end;
}

.page-about .about-intro__head h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(34px, 6vw, 72px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0.32em 0 0;
  color: var(--paper);
}

.page-about .about-intro__lead {
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.8;
  color: var(--coolgray);
  margin: 0;
}

.page-about .about-index {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  border-top: 1px solid var(--about-hair);
}

.page-about .about-index li {
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-index a {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 13px 2px;
  color: var(--paper);
  text-decoration: none;
  font-size: 15px;
  transition: color 0.2s var(--ease);
}

.page-about .about-index a::after {
  content: "↘";
  margin-left: auto;
  color: var(--gold);
  font-size: 13px;
}

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

.page-about .about-index__num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--graygold);
  flex: none;
}

/* 通用章节骨架 */
.page-about .about-section {
  padding: var(--about-block) 0;
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-section__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3.4vw, 40px);
}

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

.page-about .about-section__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(25px, 3.4vw, 42px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin: 0.34em 0 0.55em;
  color: var(--paper);
}

.page-about .about-section__note {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--graygold);
  max-width: 34em;
}

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

.page-about .about-text {
  margin: 0 0 16px;
  font-size: clamp(15px, 1.5vw, 16.5px);
  line-height: 1.85;
  color: var(--coolgray);
  overflow-wrap: anywhere;
}

.page-about .about-figure {
  margin: 26px 0;
}

/* 年代刻度 */
.page-about .about-years {
  list-style: none;
  margin: 26px 0;
  padding: 0;
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-years__item {
  display: grid;
  grid-template-columns: 4.4rem minmax(0, 1fr);
  gap: 14px;
  padding: 15px 0;
  border-top: 1px solid var(--about-hair);
  position: relative;
}

.page-about .about-years__item::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 0;
  width: 1px;
  height: 26px;
  background: var(--gold);
}

.page-about .about-years__year {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--gold);
}

.page-about .about-years__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--paper);
}

/* 统计条 */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
  margin: 0 0 26px;
}

.page-about .about-stat {
  background: var(--ink-2);
  padding: 16px 18px;
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(19px, 2.4vw, 26px);
  color: var(--gold-light);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stat__label {
  display: block;
  margin-top: 6px;
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--coolgray);
}

/* 增长曲线 */
.page-about .about-curve-box {
  border: 1px solid var(--about-hair);
  background: linear-gradient(180deg, rgba(201, 164, 92, 0.06), rgba(11, 12, 14, 0) 72%);
  padding: 16px;
}

.page-about .about-curve {
  display: block;
  width: 100%;
  height: auto;
}

/* 文档目录树 */
.page-about .about-tree {
  margin: 22px 0 0;
  border-left: 1px solid var(--about-ruler);
  padding-left: 16px;
}

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

.page-about .about-tree__node > summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 13px 0;
  font-size: 15.5px;
  color: var(--paper);
}

.page-about .about-tree__node > summary::-webkit-details-marker {
  display: none;
}

.page-about .about-tree__node > summary::before {
  content: "";
  flex: none;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--celadon);
  box-shadow: 0 0 0 3px rgba(95, 143, 122, 0.16);
}

.page-about .about-tree__node > summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--graygold);
}

.page-about .about-tree__node[open] > summary::after {
  content: "–";
  color: var(--gold);
}

.page-about .about-tree__node:focus-within > summary {
  color: var(--gold-light);
}

.page-about .about-tree__list {
  list-style: none;
  margin: 0 0 14px;
  padding: 0 0 0 17px;
}

.page-about .about-tree__list li {
  position: relative;
  padding: 5px 0 5px 14px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--coolgray);
}

.page-about .about-tree__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 15px;
  width: 6px;
  height: 1px;
  background: var(--hair);
}

/* 三列工序 */
.page-about .about-roles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
  margin-bottom: 26px;
}

.page-about .about-role {
  background: var(--ink-2);
  padding: 20px 18px;
}

.page-about .about-role__tag {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--gold);
}

.page-about .about-role__title {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  margin: 10px 0 8px;
  color: var(--paper);
}

.page-about .about-role p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--coolgray);
}

/* 团队数据 */
.page-about .about-metrics {
  list-style: none;
  margin: 0 0 26px;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .about-metrics li {
  border-top: 1px solid var(--gold);
  padding-top: 12px;
  min-width: 0;
}

.page-about .about-metrics strong {
  display: block;
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: clamp(22px, 3vw, 30px);
  color: var(--paper);
  font-variant-numeric: tabular-nums;
}

.page-about .about-metrics span {
  display: block;
  margin-top: 6px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--graygold);
}

/* 反馈面板 */
.page-about .about-support {
  padding: var(--about-block) 0;
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-support__panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
  border: 1px solid var(--about-ruler);
  background: linear-gradient(135deg, rgba(201, 164, 92, 0.1), rgba(11, 12, 14, 0) 62%);
  padding: clamp(22px, 4vw, 44px);
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}

.page-about .about-contact {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-contact li {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 3px;
  padding: 12px 0;
  border-top: 1px solid var(--about-hair);
}

.page-about .about-contact li:first-child {
  border-top: none;
  padding-top: 0;
}

.page-about .about-contact__key {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--graygold);
}

.page-about .about-contact__val {
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--paper);
  overflow-wrap: anywhere;
}

/* 相关入口 */
.page-about .about-next {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
  margin-top: clamp(40px, 6vw, 72px);
  margin-bottom: clamp(48px, 7vw, 88px);
}

.page-about .about-next__link {
  display: block;
  background: var(--ink-2);
  padding: 22px 20px;
  text-decoration: none;
  color: var(--paper);
  transition: background 0.2s var(--ease);
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  background: var(--smoke);
}

.page-about .about-next__label {
  display: block;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  color: var(--gold-light);
}

.page-about .about-next__desc {
  display: block;
  margin-top: 8px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--coolgray);
}

@media (min-width: 640px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

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

  .page-about .about-contact li {
    grid-template-columns: 5.5rem minmax(0, 1fr);
    align-items: baseline;
    gap: 12px;
  }
}

@media (min-width: 900px) {
  .page-about .about-intro__inner {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: end;
  }

  .page-about .about-section__grid {
    grid-template-columns: minmax(230px, 0.82fr) minmax(0, 1.55fr);
    gap: clamp(32px, 5vw, 76px);
    align-items: start;
  }

  .page-about .about-section__rail {
    position: sticky;
    top: calc(var(--header-h) + 28px);
  }

  .page-about .about-support__panel {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
  }
}

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

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index a,
  .page-about .about-next__link {
    transition: none;
  }
}
<<<END>>>