.page-about {
  --about-rail-w: 232px;
  --about-radius: 28px;
  background: var(--ink-950);
  color: var(--ice);
  padding-bottom: 72px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: calc(var(--header-h) + 44px) 0 52px;
  background:
    radial-gradient(880px 460px at 88% -12%, rgba(213, 43, 30, .22), transparent 62%),
    radial-gradient(720px 420px at 6% 4%, rgba(21, 94, 134, .38), transparent 62%),
    var(--ink-950);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--ink-600), transparent);
}

.page-about .about-hero__grid {
  display: grid;
  gap: 30px;
  margin-top: 22px;
}

.page-about .about-hero h1 {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(2rem, 5.6vw, 3.75rem);
  line-height: 1.18;
  letter-spacing: .02em;
  color: var(--white);
  margin: 12px 0 16px;
  max-width: 15ch;
}

.page-about .about-hero .lead {
  color: var(--ice);
  font-size: 1rem;
  line-height: 1.8;
  max-width: 56ch;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.page-about .about-hero__facts li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: rgba(11, 60, 93, .5);
  min-width: 0;
}

.page-about .about-hero__facts .mono {
  font-size: 1.5rem;
  line-height: 1.1;
  color: var(--gold);
}

.page-about .about-hero__facts li span:last-child {
  font-size: .8125rem;
  color: var(--ice);
}

/* ---------- 骨架：左窄右宽 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  margin-top: 48px;
}

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

/* ---------- 左侧时间线 ---------- */
.page-about .about-rail {
  min-width: 0;
}

.page-about .about-rail__title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: .75rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--ink-600);
}

.page-about .rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 12px;
  overflow-x: auto;
  padding-bottom: 6px;
  scrollbar-width: thin;
}

.page-about .rail-item {
  position: relative;
  flex: 0 0 auto;
  min-width: 0;
}

.page-about .rail-item::before,
.page-about .rail-item::after {
  display: none;
}

.page-about .rail-link {
  display: flex;
  flex-direction: column;
  gap: 5px;
  min-width: 168px;
  padding: 13px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: rgba(11, 60, 93, .45);
  text-decoration: none;
  color: inherit;
  transition: transform .18s ease, border-color .18s ease;
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  transform: translateY(-2px);
  border-color: var(--ink-600);
}

.page-about .rail-item.is-current .rail-link {
  border-color: rgba(213, 43, 30, .7);
  background: rgba(213, 43, 30, .12);
}

.page-about .rail-year {
  align-self: flex-start;
  font-family: var(--font-serif);
  font-size: .8125rem;
  letter-spacing: .08em;
  color: var(--gold);
  border: 1px solid rgba(242, 183, 5, .45);
  border-radius: 999px;
  padding: 1px 10px;
}

.page-about .rail-name {
  font-size: .9375rem;
  font-weight: 500;
  color: var(--white);
}

.page-about .rail-desc {
  font-size: .8125rem;
  line-height: 1.55;
  color: var(--ice);
}

.page-about .rail-side {
  display: none;
  margin-top: 22px;
  font-size: .8125rem;
  color: var(--ice);
  text-decoration: none;
  border-bottom: 1px dashed var(--ink-600);
  padding-bottom: 2px;
}

.page-about .rail-side:hover {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  padding: 40px 0;
  border-bottom: 1px solid rgba(42, 59, 73, .6);
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .about-section--last {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-section__head {
  max-width: 62ch;
  margin-bottom: 26px;
}

.page-about .about-section__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(1.5rem, 3.6vw, 2.25rem);
  line-height: 1.3;
  letter-spacing: .02em;
  color: var(--white);
  margin: 8px 0 10px;
}

.page-about .about-section__lead {
  color: var(--ice);
  line-height: 1.78;
  font-size: .9375rem;
}

.page-about .about-section p {
  line-height: 1.8;
  font-size: .9375rem;
  color: var(--ice);
}

.page-about .about-section p + p {
  margin-top: 14px;
}

.page-about .about-tail {
  margin-top: 22px;
  padding-left: 16px;
  border-left: 2px solid var(--ink-600);
  color: var(--ice);
}

/* ---------- 视角分栏 ---------- */
.page-about .about-split {
  display: grid;
  gap: 26px;
}

.page-about .about-split__text p {
  margin: 0;
}

.page-about .about-split__text p + p {
  margin-top: 14px;
}

/* ---------- 媒体占位 ---------- */
.page-about .about-fig,
.page-about .about-wide-fig {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: linear-gradient(160deg, var(--ink-900), var(--ink-800));
}

.page-about .about-wide-fig {
  margin-top: 24px;
}

.page-about .about-fig .media__frame,
.page-about .about-wide-fig .media__frame {
  line-height: 0;
  background: linear-gradient(160deg, var(--ink-900), var(--ink-800));
}

.page-about .about-fig .media__frame {
  border-radius: 0;
}

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

.page-about .about-fig .media__caption,
.page-about .about-wide-fig .media__caption {
  padding: 12px 16px;
  font-size: .8125rem;
  line-height: 1.6;
  color: var(--ice);
}

/* ---------- 三层结构 ---------- */
.page-about .tier-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .tier {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: 14px;
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--ink-600);
  border-radius: var(--radius-md);
  background: rgba(11, 60, 93, .38);
}

.page-about .tier:nth-child(1) {
  border-left-color: var(--red);
}

.page-about .tier:nth-child(3) {
  border-left-color: var(--ink-600);
  background: rgba(8, 23, 38, .72);
}

.page-about .tier__num {
  font-size: 1.375rem;
  line-height: 1.1;
  color: var(--gold);
  padding-top: 2px;
}

.page-about .tier__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: .02em;
  color: var(--white);
  margin: 0 0 8px;
}

.page-about .tier__body p {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.78;
}

/* ---------- 版本卡片 ---------- */
.page-about .version-stack {
  display: grid;
  gap: 16px;
}

.page-about .version {
  position: relative;
  padding: 22px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: linear-gradient(150deg, rgba(11, 60, 93, .78), rgba(8, 23, 38, .92));
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .version:target {
  border-color: rgba(242, 183, 5, .65);
}

.page-about .version__top {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.page-about .version__no {
  font-size: 1.0625rem;
  color: var(--gold);
}

.page-about .archive-mark {
  font-family: var(--font-serif);
  font-size: .8125rem;
  letter-spacing: .08em;
  color: var(--ice);
  border-bottom: 1px dotted var(--ink-600);
  padding-bottom: 2px;
}

.page-about .version__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.1875rem;
  letter-spacing: .02em;
  color: var(--white);
  margin: 0 0 10px;
}

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

.page-about .version__points li {
  position: relative;
  padding-left: 16px;
  font-size: .875rem;
  line-height: 1.72;
  color: var(--ice);
}

.page-about .version__points li + li {
  margin-top: 6px;
}

.page-about .version__points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .65em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--ink-600);
}

.page-about .version .btn {
  margin-top: 18px;
}

/* ---------- 内容来源 ---------- */
.page-about .sources {
  display: grid;
  gap: 14px;
}

.page-about .source {
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-top: 3px solid var(--ink-600);
  border-radius: var(--radius-md);
  background: rgba(11, 60, 93, .3);
}

.page-about .source:nth-child(1) {
  border-top-color: var(--red);
}

.page-about .source:nth-child(2) {
  border-top-color: var(--gold);
}

.page-about .source__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: .02em;
  color: var(--white);
  margin: 0 0 10px;
}

.page-about .source__num {
  font-size: 1.375rem;
  color: var(--gold);
  margin: 0 0 12px;
  border-bottom: 1px solid rgba(242, 183, 5, .3);
  padding-bottom: 10px;
}

.page-about .source p {
  margin: 0;
  font-size: .875rem;
  line-height: 1.75;
}

/* ---------- 团队筛选 ---------- */
.page-about .filter-bar {
  flex-wrap: wrap;
  margin-top: 26px;
  margin-bottom: 22px;
}

.page-about .filter-bar__status {
  align-self: center;
  font-size: .8125rem;
  color: var(--gold);
}

.page-about .team-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .team-card {
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: rgba(11, 60, 93, .34);
}

.page-about .team-card__avatar {
  display: block;
  width: 42px;
  height: 42px;
  border-radius: 14px;
  margin-bottom: 14px;
  background: linear-gradient(135deg, var(--ink-600), var(--red));
}

.page-about .team-card[data-keys~="data"] .team-card__avatar {
  background: linear-gradient(135deg, var(--gold), var(--red-dark));
}

.page-about .team-card[data-keys~="tech"] .team-card__avatar {
  background: linear-gradient(135deg, var(--ink-800), var(--ink-600));
}

.page-about .team-card[data-keys~="service"] .team-card__avatar {
  background: linear-gradient(135deg, var(--ink-600), var(--gold));
}

.page-about .team-card__role {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: .02em;
  color: var(--white);
}

.page-about .team-card__count {
  margin: 4px 0 12px;
  font-size: 1.875rem;
  line-height: 1;
  color: var(--gold);
}

.page-about .team-card__desc {
  margin: 0;
  font-size: .875rem;
  line-height: 1.75;
}

/* ---------- 运营归属（浅色区） ---------- */
.page-about .about-section--cement {
  background: var(--cement);
  border-radius: var(--radius-lg);
  border-bottom: 0;
  padding: 30px 20px;
  margin-top: 8px;
  color: var(--graphite);
}

.page-about .about-section--cement .about-section__title {
  color: var(--graphite);
}

.page-about .about-section--cement .eyebrow {
  color: var(--red-dark);
}

.page-about .region-grid {
  display: grid;
  gap: 22px;
}

.page-about .region-block__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: .02em;
  color: var(--graphite);
  margin: 0 0 10px;
}

.page-about .about-section--cement p {
  color: #3C464E;
  font-size: .9375rem;
  line-height: 1.8;
  margin: 0;
}

.page-about .region-contact {
  margin: 0;
}

.page-about .region-contact li {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 12px;
  padding: 9px 0;
  border-bottom: 1px solid var(--cement-deep);
  font-size: .875rem;
}

.page-about .region-contact__key {
  min-width: 4.5em;
  color: #6B747B;
}

.page-about .region-contact .mono {
  color: var(--graphite);
  font-size: .875rem;
  word-break: break-all;
}

.page-about .region-note {
  margin-top: 14px !important;
  font-size: .8125rem !important;
  color: #6B747B !important;
}

/* ---------- 合作 ---------- */
.page-about .coop-list {
  display: grid;
  gap: 14px;
}

.page-about .coop {
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: rgba(8, 23, 38, .7);
}

.page-about .coop__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: .02em;
  color: var(--white);
  margin: 0 0 10px;
  padding-left: 12px;
  border-left: 3px solid var(--red);
  line-height: 1.4;
}

.page-about .coop p {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.78;
}

.page-about .coop-cta {
  margin-top: 24px;
  padding: 22px 20px;
  border-radius: var(--radius-md);
  background: linear-gradient(120deg, rgba(213, 43, 30, .16), rgba(11, 60, 93, .5));
  border: 1px solid var(--line);
}

.page-about .coop-cta p {
  margin: 0 0 16px;
  max-width: 58ch;
}

/* ---------- 桌面端 ---------- */
@media (min-width: 760px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .source:nth-child(2) {
    margin-top: 20px;
  }

  .page-about .source:nth-child(3) {
    margin-top: 40px;
  }

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

  .page-about .team-card:nth-child(even) {
    margin-top: 20px;
  }

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

  .page-about .region-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 32px;
  }

  .page-about .about-section--cement {
    padding: 36px 30px;
  }

  .page-about .version {
    padding: 26px 24px;
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, .65fr);
    gap: 48px;
    align-items: end;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, .82fr);
    gap: 44px;
    align-items: start;
  }
}

@media (min-width: 1000px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 60px;
    margin-top: 64px;
  }

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

  .page-about .rail-list {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .rail-item {
    padding-left: 28px;
    padding-bottom: 26px;
  }

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

  .page-about .rail-item::before {
    content: "";
    display: block;
    position: absolute;
    left: 7px;
    top: 22px;
    bottom: 0;
    width: 2px;
    background: var(--line);
  }

  .page-about .rail-item:last-child::before {
    display: none;
  }

  .page-about .rail-item::after {
    content: "";
    display: block;
    position: absolute;
    left: 0;
    top: 5px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    border: 2px solid var(--ink-600);
    background: var(--ink-950);
  }

  .page-about .rail-item.is-current::after {
    border-color: var(--red);
    background: var(--red);
  }

  .page-about .rail-link {
    min-width: 0;
    padding: 0;
    border: 0;
    background: none;
    border-radius: 0;
  }

  .page-about .rail-link:hover,
  .page-about .rail-link:focus-visible {
    transform: none;
  }

  .page-about .rail-item.is-current .rail-link {
    background: none;
    border: 0;
  }

  .page-about .rail-link:hover .rail-name,
  .page-about .rail-link:focus-visible .rail-name {
    color: var(--gold);
  }

  .page-about .rail-side {
    display: inline-block;
  }

  .page-about .version:nth-child(2) {
    margin-left: 26px;
  }

  .page-about .version:nth-child(3) {
    margin-left: 52px;
  }

  .page-about .about-section {
    padding: 52px 0;
  }

  .page-about .about-section--cement {
    padding: 42px 40px;
  }
}

@media (min-width: 1180px) {
  .page-about .about-hero {
    padding-top: calc(var(--header-h) + 64px);
    padding-bottom: 68px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .rail-link {
    transition: none;
  }

  .page-about .rail-link:hover,
  .page-about .rail-link:focus-visible {
    transform: none;
  }
}