.page-about {
  --about-rail: 236px;
  --about-gap: clamp(28px, 4vw, 56px);
  color: var(--white);
}

/* ---------- 上下文与首屏 ---------- */
.page-about .about-crumb-sep {
  color: var(--gray);
}

.page-about .breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-top: clamp(16px, 3vw, 28px);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--muted);
}

.page-about .breadcrumbs a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .16s ease, border-color .16s ease;
}

.page-about .breadcrumbs a:hover {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

.page-about .breadcrumbs [aria-current="page"] {
  color: var(--white);
}

.page-about .about-hero {
  padding-block: clamp(26px, 4.5vw, 52px) clamp(32px, 5vw, 60px);
  border-bottom: var(--bw) solid var(--line-strong);
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  max-width: 20ch;
  font-size: clamp(30px, 5.6vw, 58px);
  font-weight: 900;
  line-height: 1.06;
  letter-spacing: -.025em;
  color: var(--white);
}

.page-about .about-hero .lede {
  margin: 20px 0 0;
  max-width: 62ch;
  font-size: clamp(16px, 1.6vw, 18px);
  line-height: 1.78;
  color: var(--muted);
}

.page-about .about-facts {
  margin: clamp(26px, 4vw, 44px) 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-strong);
  border: var(--bw) solid var(--line-strong);
}

.page-about .about-facts__item {
  background: var(--panel);
  padding: 16px 18px 18px;
}

.page-about .about-facts dt {
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--gray);
}

.page-about .about-facts dd {
  margin: 8px 0 0;
  font-size: clamp(18px, 2.4vw, 26px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -.01em;
  color: var(--orange);
}

/* ---------- 主体双栏 ---------- */
.page-about .about-body {
  display: grid;
  gap: var(--about-gap);
  padding-block: clamp(32px, 5vw, 64px);
  align-items: start;
}

.page-about .about-index {
  border: var(--bw) solid var(--line-strong);
  background: var(--panel);
  padding: 16px 14px 10px;
}

.page-about .about-index__title {
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--orange);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .about-index__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 10px;
  font-size: 14px;
  line-height: 1.4;
  color: var(--muted);
  text-decoration: none;
  border-left: var(--bw) solid transparent;
  transition: color .16s ease, border-color .16s ease, background-color .16s ease;
}

.page-about .about-index__no {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--gray);
}

.page-about .about-index__link:hover {
  color: var(--white);
  border-left-color: var(--orange-soft);
}

.page-about .about-index__link.is-active {
  color: var(--white);
  border-left-color: var(--orange);
  background: rgba(255, 90, 31, .12);
}

.page-about .about-index__link.is-active .about-index__no {
  color: var(--orange);
}

/* ---------- 章节 ---------- */
.page-about .chapter {
  padding-block: clamp(30px, 5vw, 58px);
  border-top: var(--bw) solid var(--line-strong);
  scroll-margin-top: 112px;
}

.page-about .chapter:first-child {
  border-top-color: var(--orange);
  padding-top: clamp(24px, 4vw, 44px);
}

.page-about .chapter__head {
  display: grid;
  gap: 10px;
  margin-bottom: clamp(20px, 3vw, 32px);
}

.page-about .chapter__no {
  display: block;
  font-size: clamp(38px, 8vw, 74px);
  font-weight: 700;
  line-height: .82;
  letter-spacing: -.03em;
  color: var(--orange);
}

@supports (-webkit-text-stroke: 1px #000) {
  .page-about .chapter__no {
    color: transparent;
    -webkit-text-stroke: 2px var(--orange);
  }
}

.page-about .chapter__title {
  margin: 0;
  font-size: clamp(22px, 3.4vw, 34px);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -.018em;
  color: var(--white);
}

.page-about .chapter__lead {
  margin: 10px 0 0;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .chapter__body > p {
  margin: 0 0 16px;
  max-width: 70ch;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--muted);
}

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

/* ---------- 图片容器 ---------- */
.page-about .media-frame {
  margin: 0 0 clamp(20px, 3vw, 32px);
  border: var(--bw) solid var(--line-strong);
  background: var(--deep);
}

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

.page-about .media-frame__caption {
  padding: 10px 14px;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--gray);
  border-top: 1px solid var(--line);
}

/* ---------- 使用场景 ---------- */
.page-about .scene-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-strong);
  border: var(--bw) solid var(--line-strong);
}

.page-about .scene-list__item {
  background: var(--ink);
  padding: 20px 18px 22px;
}

.page-about .scene-list__no {
  display: block;
  font-size: 12px;
  letter-spacing: .24em;
  color: var(--orange);
}

.page-about .scene-list__title {
  margin: 10px 0 8px;
  font-size: 18px;
  font-weight: 800;
  line-height: 1.35;
  color: var(--white);
}

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

/* ---------- 发布流程 ---------- */
.page-about .flow-steps {
  list-style: none;
  margin: 0 0 clamp(20px, 3vw, 30px);
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-strong);
  border: var(--bw) solid var(--line-strong);
}

.page-about .flow-steps__item {
  background: var(--panel);
  padding: 20px 18px 22px;
}

.page-about .flow-steps__no {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
}

.page-about .flow-steps__title {
  margin: 10px 0 8px;
  font-size: 17px;
  font-weight: 800;
  color: var(--white);
}

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

/* ---------- 指标条 ---------- */
.page-about .about-metrics {
  list-style: none;
  margin: 0 0 clamp(20px, 3vw, 30px);
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .about-metrics__item {
  padding: 4px 0 4px 14px;
  border-left: var(--bw) solid var(--orange);
}

.page-about .about-metrics__value {
  display: block;
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--white);
}

.page-about .about-metrics__label {
  display: block;
  margin-top: 8px;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--gray);
}

/* ---------- 团队角色 ---------- */
.page-about .role-grid {
  list-style: none;
  margin: 0 0 clamp(20px, 3vw, 30px);
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .role-card {
  background: var(--panel);
  border: var(--bw) solid var(--line-strong);
  padding: 20px 18px 22px;
  box-shadow: var(--shadow-hard);
  transition: transform .18s ease, border-color .18s ease;
}

.page-about .role-card:hover {
  transform: translate(-2px, -2px);
  border-color: var(--orange);
}

.page-about .role-card__count {
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--orange);
}

.page-about .role-card__title {
  margin: 10px 0 8px;
  font-size: 19px;
  font-weight: 800;
  color: var(--white);
}

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

/* ---------- 版本轨道 ---------- */
.page-about .track {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .track__item {
  position: relative;
  padding: 0 0 26px 34px;
}

.page-about .track__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 5px;
  width: 12px;
  height: 12px;
  background: var(--ink);
  border: var(--bw) solid var(--orange);
}

.page-about .track__item::after {
  content: "";
  position: absolute;
  left: 7px;
  top: 23px;
  bottom: 0;
  width: var(--bw);
  background: var(--line-strong);
}

.page-about .track__item:last-child {
  padding-bottom: 0;
}

.page-about .track__item:last-child::after {
  display: none;
}

.page-about .track__year {
  display: block;
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--cyan);
}

.page-about .track__title {
  margin: 8px 0 8px;
  font-size: 19px;
  font-weight: 800;
  line-height: 1.35;
  color: var(--white);
}

.page-about .track__item > p {
  margin: 0 0 12px;
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.74;
  color: var(--muted);
}

/* ---------- 展开组件 ---------- */
.page-about .disclosure {
  max-width: 68ch;
  border: var(--bw) solid var(--line-strong);
  background: var(--panel);
}

.page-about .disclosure__trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 14px;
  background: none;
  border: 0;
  cursor: pointer;
  color: var(--white);
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  text-align: left;
  transition: color .16s ease, background-color .16s ease;
}

.page-about .disclosure__trigger:hover {
  color: var(--orange);
  background: rgba(255, 90, 31, .08);
}

.page-about .disclosure__mark {
  flex: none;
  font-family: var(--mono);
  font-size: 16px;
  line-height: 1;
  color: var(--orange);
}

.page-about .disclosure__panel {
  padding: 0 14px 14px;
  border-top: 1px solid var(--line);
}

.page-about .disclosure__panel p {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--muted);
}

/* ---------- 合作生态 ---------- */
.page-about .network-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: 0 0 clamp(20px, 3vw, 30px);
  background: var(--line-strong);
  border: var(--bw) solid var(--line-strong);
}

.page-about .network-cell {
  background: var(--deep);
  padding: 22px 20px 24px;
}

.page-about .network-cell__value {
  display: block;
  font-size: clamp(30px, 4.4vw, 46px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.03em;
  color: var(--orange);
}

.page-about .network-cell__label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--white);
}

.page-about .network-cell p {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 长期维护清单 ---------- */
.page-about .keep-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: var(--bw) solid var(--line-strong);
}

.page-about .keep-list__item {
  display: grid;
  gap: 8px;
  padding: 18px 0 20px;
  border-bottom: 1px solid var(--line);
}

.page-about .keep-list__term {
  font-size: 15px;
  font-weight: 800;
  letter-spacing: .02em;
  color: var(--orange-soft);
}

.page-about .keep-list__desc {
  margin: 0;
  max-width: 70ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--muted);
}

/* ---------- 收尾入口 ---------- */
.page-about .about-cta {
  margin-top: clamp(34px, 6vw, 68px);
  padding: clamp(24px, 4vw, 40px);
  border: var(--bw) solid var(--orange);
  background: var(--deep);
  box-shadow: var(--shadow-hard);
}

.page-about .about-cta h2 {
  margin: 0 0 12px;
  font-size: clamp(22px, 3.2vw, 30px);
  font-weight: 800;
  letter-spacing: -.018em;
  color: var(--white);
}

.page-about .about-cta p {
  margin: 0 0 22px;
  max-width: 64ch;
  font-size: 15.5px;
  line-height: 1.76;
  color: var(--muted);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 780px) {
  .page-about .chapter__head {
    grid-template-columns: auto minmax(0, 1fr);
    gap: clamp(18px, 3vw, 34px);
    align-items: start;
  }

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

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

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

  .page-about .keep-list__item {
    grid-template-columns: minmax(0, 190px) minmax(0, 1fr);
    gap: 26px;
    align-items: start;
  }
}

@media (min-width: 980px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(32px, 5vw, 72px);
  }

  .page-about .about-rail {
    position: sticky;
    top: 112px;
  }
}

@media (min-width: 1080px) {
  .page-about .about-metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 420px) {
  .page-about .about-facts dd {
    font-size: 17px;
  }

  .page-about .chapter__no {
    font-size: 34px;
  }
}