.page-about {
  --tint: #DCE6F0;
  --pad: 20px;
  --about-rule: 2px solid var(--silver-line);
  background: var(--paper);
  color: var(--charcoal);
  font-family: var(--font-sans);
}

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

.page-about .ab-shell {
  width: 100%;
  max-width: 1360px;
  margin: 0 auto;
  padding-left: var(--pad);
  padding-right: var(--pad);
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  background: var(--blue);
  color: var(--white);
  padding-top: 24px;
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(90deg, rgba(255, 255, 255, .08) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(0deg, rgba(255, 255, 255, .08) 0 1px, transparent 1px 96px);
  pointer-events: none;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  top: -25%;
  right: -32%;
  width: 72%;
  height: 150%;
  background: var(--blue-deep);
  transform: rotate(12deg);
  opacity: .75;
  pointer-events: none;
}

.page-about .ab-hero__inner {
  position: relative;
  z-index: 1;
  padding-bottom: 28px;
}

.page-about .ab-hero .crumbs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 10px;
  margin: 0 0 22px;
  padding: 0;
  list-style: none;
  font-size: 12px;
}

.page-about .ab-hero .crumbs__list li {
  color: rgba(255, 255, 255, .72);
}

.page-about .ab-hero .crumbs__list li + li::before {
  content: "/";
  margin-right: 10px;
  color: var(--orange);
}

.page-about .ab-hero .crumbs__link {
  color: var(--white);
  text-decoration: none;
  border-bottom: 2px solid var(--orange);
}

.page-about .ab-hero .crumbs__link:hover,
.page-about .ab-hero .crumbs__link:focus-visible {
  color: var(--orange-soft);
}

.page-about .ab-hero__kicker {
  margin: 0 0 14px;
  color: var(--silver);
}

.page-about .ab-hero__title {
  margin: 0 0 18px;
  max-width: 16em;
  font-size: clamp(30px, 6.6vw, 64px);
  font-weight: 200;
  line-height: 1.08;
  letter-spacing: -.02em;
}

.page-about .ab-hero__lede {
  margin: 0;
  max-width: 60ch;
  font-size: 16px;
  line-height: 1.75;
  color: rgba(255, 255, 255, .86);
}

.page-about .ab-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 18px 36px;
  margin: 30px 0 0;
  padding: 22px 0 0;
  list-style: none;
  border-top: 2px solid rgba(255, 255, 255, .24);
}

.page-about .ab-facts__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--white);
}

.page-about .ab-facts__cap {
  display: block;
  margin-top: 8px;
  font-size: 11px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, .74);
}

.page-about .ab-hero__media {
  position: relative;
  z-index: 1;
  border-top: 2px solid var(--silver);
}

.page-about .ab-hero__media img {
  display: block;
  width: 100%;
  height: 200px;
  object-fit: cover;
}

/* ---------- 主体骨架 ---------- */

.page-about .ab-body {
  padding-top: 40px;
  padding-bottom: 8px;
}

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

.page-about .ab-toc {
  margin-bottom: 36px;
}

.page-about .ab-toc__title {
  margin: 0 0 12px;
  color: var(--muted);
}

.page-about .ab-toc__list {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 14px;
  margin: 0;
  padding: 0;
  list-style: none;
  border-left: none;
}

.page-about .ab-toc__link {
  display: inline-block;
  padding: 6px 0;
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 2px solid transparent;
}

.page-about .ab-toc__link:hover,
.page-about .ab-toc__link:focus-visible {
  color: var(--charcoal);
  border-bottom-color: var(--orange);
}

.page-about .ab-toc__num {
  margin-right: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--silver-line);
}

/* ---------- 章节通用 ---------- */

.page-about .ab-sec {
  margin-bottom: 64px;
  scroll-margin-top: 88px;
}

.page-about .ab-sec__idx {
  margin: 0 0 12px;
  color: var(--muted);
}

.page-about .ab-sec__title {
  margin: 0 0 16px;
  font-size: clamp(23px, 4.2vw, 36px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -.01em;
  color: var(--blue-deep);
}

.page-about .ab-prose {
  max-width: 68ch;
  font-size: 16px;
  line-height: 1.75;
  color: var(--charcoal);
}

.page-about .ab-prose p {
  margin: 0 0 12px;
}

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

.page-about .ab-note {
  margin: 18px 0 0;
  max-width: 68ch;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
  padding-left: 14px;
  border-left: 2px solid var(--orange);
}

/* ---------- 01 演进阶段 ---------- */

.page-about .ab-timeline {
  position: relative;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 20px;
  width: 2px;
  background: var(--silver);
}

.page-about .ab-timeline__item {
  position: relative;
  padding: 0 0 30px 34px;
}

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

.page-about .ab-timeline__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  width: 12px;
  height: 12px;
  background: var(--paper);
  border: 2px solid var(--orange);
}

.page-about .ab-timeline__year {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--orange);
}

.page-about .ab-timeline__name {
  margin: 6px 0 8px;
  font-size: 19px;
  font-weight: 700;
  line-height: 1.35;
  color: var(--charcoal);
}

.page-about .ab-timeline__text {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--charcoal);
}

/* ---------- 02 双线拆分 ---------- */

.page-about .ab-sec--tint {
  background: var(--tint);
  border: 2px solid var(--blue-deep);
  box-shadow: var(--hard);
  padding: 24px var(--pad);
}

.page-about .ab-table-wrap {
  margin-top: 24px;
  overflow-x: auto;
  border: 2px solid var(--blue-deep);
  background: var(--white);
}

.page-about .ab-table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
  font-size: 14px;
  line-height: 1.6;
}

.page-about .ab-table caption {
  caption-side: top;
  padding: 12px 14px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--muted);
  background: var(--white);
  border-bottom: 2px solid var(--blue-deep);
}

.page-about .ab-table th,
.page-about .ab-table td {
  padding: 12px 14px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--silver-line);
}

.page-about .ab-table thead th {
  background: var(--blue-deep);
  color: var(--white);
  font-size: 12px;
  letter-spacing: .08em;
  border-bottom: 2px solid var(--blue-deep);
}

.page-about .ab-table tbody th {
  width: 28%;
  background: var(--white);
  color: var(--blue-deep);
  font-weight: 600;
}

.page-about .ab-table tbody td:nth-child(2) {
  border-right: 2px solid var(--silver);
}

.page-about .ab-table tbody tr:last-child th,
.page-about .ab-table tbody tr:last-child td {
  border-bottom: 0;
}

.page-about .ab-table tbody tr:hover th,
.page-about .ab-table tbody tr:hover td {
  background: rgba(232, 106, 43, .08);
}

/* ---------- 03 参数核查 ---------- */

.page-about .ab-verify {
  margin-top: 26px;
}

.page-about .ab-step {
  background: var(--white);
  border: 2px solid var(--blue-deep);
  box-shadow: var(--hard);
  margin-bottom: 18px;
}

.page-about .ab-step:last-of-type {
  margin-bottom: 0;
}

.page-about .ab-step__sum {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
  padding: 18px var(--pad);
  cursor: pointer;
  list-style: none;
}

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

.page-about .ab-step__sum::after {
  content: "＋";
  margin-left: 8px;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--orange);
}

.page-about .ab-step[open] .ab-step__sum::after {
  content: "－";
}

.page-about .ab-step__sum:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: -4px;
}

.page-about .ab-step__no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--orange);
}

.page-about .ab-step__name {
  font-size: 19px;
  font-weight: 700;
  color: var(--blue-deep);
}

.page-about .ab-step__meta {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--muted);
}

.page-about .ab-step__body {
  padding: 4px var(--pad) 18px;
  border-top: 2px solid var(--silver);
}

.page-about .ab-step__row {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--silver);
}

.page-about .ab-step__row:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .ab-step__key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--muted);
  padding-top: 3px;
}

.page-about .ab-step__row p {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--charcoal);
}

.page-about .ab-verify__aside {
  margin-top: 26px;
}

.page-about .ab-verify__frame,
.page-about .ab-hub-frame {
  margin: 0;
}

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

.page-about .ab-hub-frame {
  margin-top: 26px;
  border: 2px solid var(--silver);
}

/* ---------- 04 团队与中转仓 ---------- */

.page-about .ab-sec--ink {
  background: var(--blue-ink);
  border: 2px solid var(--blue-ink);
  box-shadow: var(--hard);
  padding: 24px var(--pad);
  color: var(--white);
}

.page-about .ab-sec--ink .ab-sec__title,
.page-about .ab-sec--ink .ab-team__name {
  color: var(--white);
}

.page-about .ab-sec--ink .ab-sec__idx,
.page-about .ab-sec--ink .label {
  color: var(--silver);
}

.page-about .ab-sec--ink .ab-prose {
  color: rgba(255, 255, 255, .84);
}

.page-about .ab-team .seg {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 24px;
}

.page-about .ab-team .seg__btn {
  font-family: var(--font-sans);
  font-size: 13px;
  padding: 10px 14px;
  border: 2px solid rgba(192, 199, 208, .4);
  background: transparent;
  color: var(--silver);
  cursor: pointer;
  transition: transform .18s var(--ease), background-color .18s var(--ease);
}

.page-about .ab-team .seg__btn:hover {
  border-color: var(--orange-soft);
}

.page-about .ab-team .seg__btn:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 2px;
}

.page-about .ab-team .seg__btn[aria-selected="true"] {
  background: var(--orange);
  border-color: var(--orange);
  color: var(--charcoal);
  font-weight: 700;
}

.page-about .seg-panel {
  margin-top: 22px;
  padding-top: 20px;
  border-top: 2px solid rgba(192, 199, 208, .4);
}

.page-about .seg-panel[hidden] {
  display: none;
}

.page-about .seg-panel:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 4px;
}

.page-about .ab-team__head {
  display: flex;
  gap: 18px;
  align-items: flex-start;
}

.page-about .ab-team__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 44px;
  font-weight: 700;
  line-height: 1;
  color: var(--orange);
}

.page-about .ab-team__name {
  margin: 0 0 6px;
  font-size: 20px;
  font-weight: 700;
}

.page-about .ab-team__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: rgba(255, 255, 255, .8);
}

.page-about .ab-team__list {
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-team__list li {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr);
  gap: 12px;
  padding: 10px 0;
  font-size: 15px;
  line-height: 1.7;
  color: rgba(255, 255, 255, .86);
  border-top: 1px solid rgba(192, 199, 208, .28);
}

.page-about .ab-team__key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--orange-soft);
  padding-top: 4px;
}

.page-about .ab-team__sub {
  margin: 34px 0 16px;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--silver);
  padding-bottom: 8px;
  border-bottom: 2px solid rgba(192, 199, 208, .35);
}

.page-about .ab-hubs {
  display: grid;
  gap: 16px;
}

.page-about .ab-hub {
  padding: 18px;
  border: 2px solid rgba(192, 199, 208, .45);
  background: rgba(255, 255, 255, .04);
}

.page-about .ab-hub__no {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--orange);
}

.page-about .ab-hub__name {
  margin: 8px 0 8px;
  font-size: 17px;
  font-weight: 700;
  color: var(--white);
}

.page-about .ab-hub p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: rgba(255, 255, 255, .78);
}

.page-about .ab-hub-frame .img-frame__tag {
  font-family: var(--font-mono);
}

/* ---------- 05 站点所在地 ---------- */

.page-about .ab-sec--local {
  border-left: 6px solid var(--orange);
  padding-left: 18px;
}

.page-about .ab-local {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  border-top: 2px solid var(--silver);
}

.page-about .ab-local__row {
  display: grid;
  gap: 4px;
  padding: 12px 0;
  border-bottom: 1px solid var(--silver);
}

.page-about .ab-local__k {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--muted);
}

.page-about .ab-local__v {
  font-size: 15px;
  line-height: 1.6;
  color: var(--charcoal);
  word-break: break-word;
}

/* ---------- 06 口径边界 ---------- */

.page-about .ab-bounds {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  border-top: 2px solid var(--blue-deep);
}

.page-about .ab-bounds__item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 14px;
  padding: 20px 0;
  border-bottom: 1px solid var(--silver);
  transition: background-color .18s var(--ease);
}

.page-about .ab-bounds__item:hover {
  background: rgba(27, 79, 138, .05);
}

.page-about .ab-bounds__no {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--orange);
  padding-top: 3px;
}

.page-about .ab-bounds__name {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--blue-deep);
}

.page-about .ab-bounds__item p {
  margin: 0;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.7;
  color: var(--charcoal);
}

/* ---------- 收束 ---------- */

.page-about .ab-cta {
  background: var(--blue-deep);
  color: var(--white);
  padding: 44px 0;
  scroll-margin-top: 88px;
}

.page-about .ab-cta__kicker {
  margin: 0 0 12px;
  color: var(--silver);
}

.page-about .ab-cta__title {
  margin: 0 0 14px;
  font-size: clamp(24px, 4.4vw, 38px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -.01em;
}

.page-about .ab-cta__lede {
  margin: 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(255, 255, 255, .84);
}

.page-about .ab-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  margin-top: 26px;
}

.page-about .ab-cta__link {
  font-size: 14px;
  color: var(--orange-soft);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  padding: 6px 0;
}

.page-about .ab-cta__link:hover,
.page-about .ab-cta__link:focus-visible {
  border-bottom-color: var(--orange);
  color: var(--white);
}

/* ---------- 响应式 ---------- */

@media (min-width: 700px) {
  .page-about .ab-hero__media img {
    height: 300px;
  }
}

@media (min-width: 900px) {
  .page-about {
    --pad: 32px;
  }

  .page-about .ab-sec--tint,
  .page-about .ab-sec--ink {
    padding: 32px;
  }

  .page-about .ab-verify {
    display: grid;
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .ab-verify__aside {
    margin-top: 0;
  }

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

  .page-about .ab-sec__idx {
    padding-left: 14px;
    border-left: 4px solid var(--orange);
  }

  .page-about .ab-local__row {
    grid-template-columns: 160px minmax(0, 1fr);
    gap: 16px;
    align-items: baseline;
  }
}

@media (min-width: 1000px) {
  .page-about .ab-body {
    display: grid;
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 60px;
    padding-top: 72px;
  }

  .page-about .ab-toc {
    align-self: start;
    position: sticky;
    top: 72px;
    margin-bottom: 0;
  }

  .page-about .ab-toc__list {
    display: block;
    border-left: 2px solid var(--silver);
  }

  .page-about .ab-toc__list li {
    display: block;
  }

  .page-about .ab-toc__link {
    display: block;
    padding: 9px 0 9px 14px;
    margin-left: -2px;
    border-left: 2px solid transparent;
    border-bottom: none;
  }

  .page-about .ab-toc__link:hover,
  .page-about .ab-toc__link:focus-visible {
    border-left-color: var(--orange);
    border-bottom: none;
  }

  .page-about .ab-sec {
    margin-bottom: 96px;
  }

  .page-about .ab-hero__media img {
    height: 400px;
  }

  .page-about .ab-cta {
    padding: 72px 0;
  }

  .page-about .ab-cta__inner {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 48px;
    align-items: center;
  }

  .page-about .ab-cta__actions {
    margin-top: 0;
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-step,
  .page-about .ab-hub,
  .page-about .ab-bounds__item,
  .page-about .ab-team .seg__btn {
    transition: none;
  }
}