.page-about {
  --ab-hero-pad: clamp(48px, 8vw, 96px);
  --ab-gap: clamp(20px, 3vw, 36px);
  --ab-mint-soft: rgba(57, 242, 200, .14);
  background: var(--paper);
  color: var(--ink-deep);
}

.page-about .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: .04em;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  background: var(--ink);
  color: var(--paper);
  padding: var(--ab-hero-pad) 0 clamp(32px, 5vw, 56px);
  overflow: hidden;
}
.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--mint), var(--red), transparent);
  opacity: .55;
}
.page-about .ab-crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0 0 clamp(20px, 4vw, 34px);
  padding: 0;
  list-style: none;
  font-size: 13px;
  color: var(--silver-dim);
}
.page-about .ab-crumbs a {
  color: var(--silver);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}
.page-about .ab-crumbs a:hover,
.page-about .ab-crumbs a:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--red);
}
.page-about .ab-hero-eyebrow {
  color: var(--gold);
  margin: 0 0 18px;
}
.page-about .ab-hero-title {
  font-family: var(--font-display);
  font-size: clamp(32px, 7vw, 66px);
  line-height: 1.08;
  letter-spacing: -.02em;
  font-weight: 800;
  margin: 0 0 22px;
  max-width: 18ch;
  text-wrap: balance;
}
.page-about .ab-hero-lead {
  max-width: 60ch;
  margin: 0 0 clamp(28px, 4vw, 44px);
  font-size: clamp(15px, 2.4vw, 18px);
  line-height: 1.8;
  color: var(--silver);
}
.page-about .ab-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 20px;
  margin: 0 0 clamp(28px, 4vw, 44px);
  padding: 0;
  list-style: none;
}
.page-about .ab-stat {
  padding-left: 14px;
  border-left: 1px solid var(--line-ink);
}
.page-about .ab-stat-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 4.4vw, 34px);
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--paper);
  line-height: 1.1;
}
.page-about .ab-stat-unit {
  font-size: .55em;
  margin-left: 2px;
  color: var(--gold);
}
.page-about .ab-stat-label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  color: var(--slate);
  letter-spacing: .04em;
}
.page-about .ab-toc {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.page-about .ab-toc-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border: 1px solid var(--line-ink);
  border-radius: var(--radius-pill);
  color: var(--silver);
  font-size: 13px;
  letter-spacing: .05em;
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}
.page-about .ab-toc-link .num {
  color: var(--red);
  font-size: 12px;
}
.page-about .ab-toc-link:hover,
.page-about .ab-toc-link:focus-visible {
  color: var(--paper);
  border-color: var(--mint);
  background: var(--ab-mint-soft);
}

/* ---------- 通用区块 ---------- */
.page-about .ab-sec {
  padding-top: clamp(48px, 7vw, 88px);
  padding-bottom: clamp(48px, 7vw, 88px);
}
.page-about .ab-sec--raised {
  background: var(--paper-raised);
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}
.page-about .ab-sec--ink {
  background: var(--ink);
  color: var(--paper);
}
.page-about .ab-sec-title {
  font-family: var(--font-display);
  font-size: clamp(26px, 5vw, 42px);
  line-height: 1.14;
  letter-spacing: -.02em;
  font-weight: 800;
  margin: 10px 0 20px;
  max-width: 22ch;
  color: var(--ink-deep);
}
.page-about .ab-sec-title--ink {
  color: var(--paper);
}
.page-about .ab-sec-head {
  margin-bottom: clamp(28px, 4vw, 48px);
}
.page-about .ab-sec-desc {
  max-width: 66ch;
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--slate);
}
.page-about .ab-sec--ink .ab-sec-desc {
  color: var(--silver);
}
.page-about .ab-eyebrow-mint {
  color: var(--mint);
}
.page-about .ab-sec--ink .eyebrow {
  color: var(--gold);
}

/* ---------- 非对称双栏 ---------- */
.page-about .ab-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--ab-gap);
}
.page-about .ab-split-aside {
  display: grid;
  gap: 18px;
  align-content: start;
}
.page-about .ab-prose p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink-deep);
}
.page-about .ab-prose p:last-child {
  margin-bottom: 0;
}
.page-about .ab-prose a {
  color: var(--red-deep);
  text-decoration: none;
  border-bottom: 1px solid rgba(209, 58, 47, .4);
}
.page-about .ab-prose a:hover,
.page-about .ab-prose a:focus-visible {
  border-bottom-color: var(--red-deep);
}
.page-about .ab-prose--ink p {
  color: var(--silver);
}
.page-about .ab-prose--ink a {
  color: var(--mint);
  border-bottom-color: rgba(57, 242, 200, .4);
}

/* 要点列表 */
.page-about .ab-points {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}
.page-about .ab-points li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  padding: 12px 14px;
  background: var(--paper-raised);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-card);
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--ink-deep);
  box-shadow: 0 1px 2px rgba(20, 32, 46, .04);
}
.page-about .ab-point-key {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border-radius: var(--radius-pill);
  background: var(--ink);
  color: var(--mint);
  font-size: 12px;
  font-weight: 700;
}

/* 图片与旁注 */
.page-about .ab-figure {
  margin: 0;
}
.page-about .ab-figure figcaption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--slate);
}
.page-about .ab-sec--ink .ab-figure figcaption {
  color: var(--slate);
}
.page-about .ab-figure--wide {
  margin: clamp(28px, 4vw, 44px) 0 0;
}
.page-about .ab-figure .media-frame {
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-card);
  overflow: hidden;
  background: var(--paper-raised);
}
.page-about .ab-sec--ink .ab-figure .media-frame {
  border-color: var(--line-ink);
  background: var(--ink-deep);
}
.page-about .ab-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}
.page-about .ab-aside-note {
  padding: 16px 18px;
  border-left: 2px solid var(--red);
  background: var(--paper-raised);
  border-radius: 0 var(--radius-card) var(--radius-card) 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--slate);
}
.page-about .ab-aside-title {
  margin: 0 0 8px;
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--ink-deep);
  font-weight: 700;
}
.page-about .ab-aside-note p {
  margin: 0;
}
.page-about .ab-aside-note a {
  color: var(--red-deep);
  text-decoration: none;
  border-bottom: 1px solid rgba(209, 58, 47, .4);
}
.page-about .ab-aside-note--plain {
  border-left-color: var(--teal);
  background: transparent;
  padding: 0 0 0 14px;
  font-size: 13.5px;
}

/* ---------- 六个栏目 ---------- */
.page-about .ab-channels {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}
.page-about .ab-channel {
  padding: 20px;
  border: 1px solid var(--line-ink);
  border-radius: var(--radius-card);
  background: rgba(244, 239, 230, .035);
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.page-about .ab-channel:hover,
.page-about .ab-channel:focus-within {
  border-color: var(--mint);
  background: rgba(57, 242, 200, .07);
  transform: translateY(-2px);
}
.page-about .ab-channel-code {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  margin: 0 0 14px;
  border: 1px solid var(--red);
  border-radius: 8px;
  color: var(--red);
  font-size: 13px;
  font-weight: 700;
}
.page-about .ab-channel-title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--paper);
}
.page-about .ab-channel-desc {
  margin: 0 0 14px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--silver);
}
.page-about .ab-channel-range {
  display: inline-block;
  padding: 4px 9px;
  border-radius: var(--radius-pill);
  background: rgba(184, 196, 206, .1);
  color: var(--gold);
  font-size: 11.5px;
  letter-spacing: .06em;
}
.page-about .ab-channel:hover .ab-channel-range,
.page-about .ab-channel:focus-within .ab-channel-range {
  background: rgba(57, 242, 200, .16);
  color: var(--mint);
}
.page-about .ab-inline-link {
  margin: clamp(24px, 3vw, 34px) 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--silver);
}
.page-about .ab-inline-link a {
  color: var(--mint);
  text-decoration: none;
  border-bottom: 1px solid rgba(57, 242, 200, .45);
  margin: 0 2px;
}

/* ---------- 对照表 ---------- */
.page-about .ab-compare {
  width: 100%;
  border-collapse: collapse;
  font-size: 13.5px;
  line-height: 1.6;
  background: var(--paper-raised);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-card);
  overflow: hidden;
}
.page-about .ab-compare caption {
  caption-side: top;
  text-align: left;
  padding: 0 0 12px;
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--slate);
}
.page-about .ab-compare th,
.page-about .ab-compare td {
  padding: 11px 12px;
  text-align: left;
  border-bottom: 1px solid var(--line-soft);
  vertical-align: top;
  color: var(--ink-deep);
}
.page-about .ab-compare thead th {
  background: var(--ink);
  color: var(--paper);
  font-weight: 700;
  font-size: 12.5px;
  letter-spacing: .06em;
}
.page-about .ab-compare thead th:first-child {
  color: var(--gold);
}
.page-about .ab-compare tbody th {
  font-weight: 600;
  color: var(--slate);
  white-space: nowrap;
}
.page-about .ab-compare tbody tr:last-child th,
.page-about .ab-compare tbody tr:last-child td {
  border-bottom: 0;
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 44px);
}
.page-about .ab-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 18px;
  border-left: 1px solid var(--line-soft);
  display: grid;
  gap: 10px;
}
.page-about .ab-node {
  position: relative;
}
.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: -23px;
  top: 20px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--paper-raised);
  border: 2px solid var(--line);
}
.page-about .ab-node:has(details[open])::before {
  background: var(--red);
  border-color: var(--red);
  box-shadow: 0 0 0 4px rgba(209, 58, 47, .12);
}
.page-about .ab-node details {
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-card);
  background: var(--paper);
  box-shadow: 0 1px 2px rgba(20, 32, 46, .04);
  overflow: hidden;
}
.page-about .ab-node details[open] {
  border-color: rgba(209, 58, 47, .38);
}
.page-about .ab-node-summary {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 12px;
  padding: 15px 16px;
  cursor: pointer;
  list-style: none;
}
.page-about .ab-node-summary::-webkit-details-marker {
  display: none;
}
.page-about .ab-node-summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--red);
}
.page-about .ab-node details[open] .ab-node-summary::after {
  content: "−";
}
.page-about .ab-node-summary:focus-visible {
  outline: 2px solid var(--teal);
  outline-offset: -2px;
}
.page-about .ab-node-year {
  font-size: 13px;
  font-weight: 700;
  color: var(--red);
  white-space: nowrap;
}
.page-about .ab-node-head {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--ink-deep);
}
.page-about .ab-node-body {
  padding: 0 16px 16px;
  border-top: 1px solid var(--line-soft);
  margin-top: 0;
}
.page-about .ab-node-body p {
  margin: 14px 0 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--slate);
}
.page-about .ab-figure--timeline {
  align-self: start;
  position: relative;
}
.page-about .ab-figure--timeline::before {
  content: "TIANJIN · GEOMETRY";
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--gold);
}

/* ---------- 团队 ---------- */
.page-about .ab-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}
.page-about .ab-role {
  padding: 16px 18px;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-card);
  background: var(--paper-raised);
  box-shadow: 0 1px 2px rgba(20, 32, 46, .04);
}
.page-about .ab-role-name {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  color: var(--ink-deep);
}
.page-about .ab-role-desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--slate);
}
.page-about .ab-role:nth-child(2) {
  border-left: 2px solid var(--teal);
}
.page-about .ab-role:nth-child(3) {
  border-left: 2px solid var(--red);
}

/* ---------- 服务与联系 ---------- */
.page-about .ab-sec--last {
  padding-bottom: clamp(56px, 8vw, 96px);
}
.page-about .ab-cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}
.page-about .ab-contact-card {
  padding: 20px;
  border: 1px solid var(--line-ink);
  border-radius: var(--radius-card);
  background: rgba(244, 239, 230, .04);
}
.page-about .ab-contact-title {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--mint);
}
.page-about .ab-contact-card .contact-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}
.page-about .ab-contact-card .contact-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line-ink);
}
.page-about .ab-contact-card .contact-row:last-of-type {
  border-bottom: 0;
  padding-bottom: 0;
}
.page-about .ab-contact-card .contact-key {
  flex: 0 0 auto;
  min-width: 34px;
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--gold);
}
.page-about .ab-contact-card .contact-val {
  flex: 1 1 auto;
  min-width: 0;
  font-family: var(--font-mono);
  font-size: 13.5px;
  word-break: break-all;
  color: var(--paper);
}
.page-about .ab-contact-card .copy-btn {
  flex: 0 0 auto;
  padding: 3px 10px;
  border: 1px solid var(--line-ink);
  border-radius: var(--radius-pill);
  background: transparent;
  color: var(--silver);
  font-size: 11.5px;
  letter-spacing: .06em;
  cursor: pointer;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}
.page-about .ab-contact-card .copy-btn:hover,
.page-about .ab-contact-card .copy-btn:focus-visible {
  border-color: var(--mint);
  color: var(--mint);
}
.page-about .ab-contact-card .copy-btn[data-copied] {
  border-color: var(--mint);
  color: var(--mint);
}
.page-about .ab-contact-card .contact-note {
  margin: 16px 0 0;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--slate);
}

/* ---------- 桌面布局 ---------- */
@media (min-width: 720px) {
  .page-about .ab-stats {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }
  .page-about .ab-channels {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }
  .page-about .ab-node-summary {
    padding: 18px 22px;
  }
  .page-about .ab-node-body {
    padding: 0 22px 20px;
  }
}

@media (min-width: 960px) {
  .page-about .ab-split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: clamp(32px, 4vw, 56px);
    align-items: start;
  }
  .page-about .ab-split--reverse {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
  }
  .page-about .ab-split--reverse .ab-split-main {
    order: 2;
  }
  .page-about .ab-split--reverse .ab-split-aside {
    order: 1;
  }
  .page-about .ab-split--contact {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
  }
  .page-about .ab-channels {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }
  .page-about .ab-channel:nth-child(2),
  .page-about .ab-channel:nth-child(5) {
    margin-top: 30px;
  }
  .page-about .ab-timeline-layout {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: clamp(32px, 4vw, 56px);
    align-items: start;
  }
  .page-about .ab-figure--timeline {
    position: sticky;
    top: calc(var(--header-offset) + 16px);
  }
  .page-about .ab-hero-title {
    max-width: 20ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-toc-link,
  .page-about .ab-channel,
  .page-about .ab-contact-card .copy-btn {
    transition: none;
  }
  .page-about .ab-channel:hover,
  .page-about .ab-channel:focus-within {
    transform: none;
  }
}
<<<END>>>