.page-about {
  --ab-line: rgba(16, 42, 67, .14);
  --ab-line-soft: rgba(16, 42, 67, .08);
  --ab-glow: rgba(217, 138, 31, .14);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  padding-block: clamp(18px, 3.4vw, 40px) clamp(44px, 7vw, 92px);
}

.page-about .ab-kicker {
  display: inline-flex;
  align-items: center;
  gap: .7em;
  margin: 0;
  font-family: var(--mono);
  font-size: .74rem;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--gold);
}

.page-about .ab-kicker::before {
  content: "";
  width: 38px;
  height: 2px;
  background: linear-gradient(90deg, var(--gold-lit), var(--gold));
}

.page-about .ab-hero__title {
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(2.4rem, 9vw, 7rem);
  line-height: 1.02;
  letter-spacing: -.015em;
  color: var(--ink);
  margin: clamp(16px, 2.4vw, 28px) 0 clamp(20px, 3vw, 34px);
}

.page-about .ab-hero__lede {
  max-width: 62ch;
  margin: 0;
  font-size: clamp(1rem, 1.4vw, 1.12rem);
  line-height: 1.75;
  color: var(--coal);
}

.page-about .ab-stats {
  list-style: none;
  margin: clamp(30px, 4.4vw, 54px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(18px, 2.4vw, 32px);
}

.page-about .ab-stats li {
  border-top: 2px solid var(--gold);
  padding-top: 14px;
}

.page-about .ab-stats__n {
  display: block;
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(1.75rem, 3.4vw, 2.85rem);
  line-height: 1;
  color: var(--ink);
}

.page-about .ab-stats__plus,
.page-about .ab-stats__unit {
  font-size: .5em;
  color: var(--gold);
  margin-left: .14em;
}

.page-about .ab-stats__l {
  display: block;
  margin-top: 10px;
  font-size: .8rem;
  letter-spacing: .04em;
  color: var(--slate);
}

/* ---------- 01 新旧双线 ---------- */
.page-about .ab-dual__grid {
  display: grid;
  gap: clamp(26px, 4vw, 52px);
  margin-top: clamp(28px, 4vw, 48px);
}

.page-about .ab-dual__copy p {
  margin: 0 0 1.1em;
  font-size: 1rem;
  line-height: 1.78;
  color: var(--coal);
}

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

.page-about .ab-dual__fig {
  margin: 0;
}

.page-about .ab-dual__fig img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  object-fit: cover;
}

.page-about .ab-lanes {
  display: grid;
  gap: clamp(16px, 2.4vw, 26px);
  margin-top: clamp(32px, 4.6vw, 56px);
}

.page-about .ab-lane {
  padding: clamp(24px, 3.4vw, 38px);
  border-radius: var(--radius);
  background: var(--paper-2);
  border-left: 4px solid var(--gold);
}

.page-about .ab-lane h3 {
  margin: 8px 0 12px;
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(1.2rem, 2.2vw, 1.5rem);
  line-height: 1.3;
  color: var(--ink);
}

.page-about .ab-lane p {
  margin: 0;
  font-size: .96rem;
  line-height: 1.75;
  color: var(--coal);
}

.page-about .ab-lane__tag {
  margin: 0;
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .16em;
  color: var(--gold);
}

.page-about .ab-lane--ink {
  background: var(--ink-2);
  border-left-color: var(--gold-lit);
}

.page-about .ab-lane--ink h3 {
  color: var(--paper);
}

.page-about .ab-lane--ink p {
  color: rgba(247, 241, 231, .82);
}

.page-about .ab-lane--ink .ab-lane__tag {
  color: var(--gold-lit);
}

/* ---------- 02 版本时间线 ---------- */
.page-about .ab-tl-wrap {
  display: grid;
  gap: clamp(30px, 4vw, 54px);
  margin-top: clamp(30px, 4.4vw, 54px);
}

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

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: linear-gradient(180deg, var(--gold-lit), var(--gold) 55%, var(--ab-line));
}

.page-about .ab-node {
  position: relative;
  padding-left: 40px;
  padding-bottom: clamp(30px, 4vw, 52px);
}

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

.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--gold);
  box-shadow: 0 0 0 5px var(--ab-glow);
}

.page-about .ab-node__year {
  margin: 0;
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(1.9rem, 4.4vw, 2.8rem);
  line-height: 1;
  color: var(--gold);
  letter-spacing: .01em;
}

.page-about .ab-node__stage {
  margin: 6px 0 10px;
  font-family: var(--mono);
  font-size: .74rem;
  letter-spacing: .16em;
  color: var(--slate);
}

.page-about .ab-node h3 {
  margin: 0 0 10px;
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(1.05rem, 1.9vw, 1.28rem);
  line-height: 1.4;
  color: var(--ink);
}

.page-about .ab-node > p:not(.ab-node__year):not(.ab-node__stage) {
  margin: 0;
  font-size: .97rem;
  line-height: 1.75;
  color: var(--coal);
  max-width: 54ch;
}

.page-about .ab-more {
  margin-top: 14px;
  border-top: 1px dashed var(--ab-line);
}

.page-about .ab-more summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 0 2px;
  font-family: var(--mono);
  font-size: .76rem;
  letter-spacing: .1em;
  color: var(--ink);
}

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

.page-about .ab-more summary::before {
  content: "+";
  display: inline-grid;
  place-items: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1px solid var(--line-gold);
  color: var(--gold);
  font-size: .9rem;
  line-height: 1;
  flex: none;
}

.page-about .ab-more[open] summary::before {
  content: "−";
}

.page-about .ab-more summary:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

.page-about .ab-more ul {
  margin: 12px 0 0;
  padding-left: 1.1em;
  font-size: .92rem;
  line-height: 1.72;
  color: var(--coal);
}

.page-about .ab-more li {
  margin-bottom: .4em;
}

.page-about .ab-tl-fig {
  margin: 0;
}

.page-about .ab-tl-fig img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  object-fit: cover;
}

/* ---------- 03 资料库与会员中心 ---------- */
.page-about .ab-lib {
  display: grid;
  gap: clamp(18px, 2.6vw, 28px);
  margin-top: clamp(28px, 4vw, 48px);
}

.page-about .ab-lib__col {
  padding: clamp(24px, 3.2vw, 36px);
  border-radius: var(--radius);
  background: var(--paper-2);
}

.page-about .ab-lib__col--ink {
  background: var(--ink);
}

.page-about .ab-lib__head {
  margin: 0 0 18px;
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(1.1rem, 2vw, 1.32rem);
  color: var(--ink);
}

.page-about .ab-lib__col--ink .ab-lib__head {
  color: var(--gold-lit);
}

.page-about .ab-filetypes,
.page-about .ab-member {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-filetypes li {
  display: grid;
  gap: 4px;
  padding: 14px 0;
  border-top: 1px solid var(--ab-line-soft);
}

.page-about .ab-filetypes li:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .ab-filetypes b {
  font-family: var(--mono);
  font-size: .82rem;
  letter-spacing: .1em;
  color: var(--gold);
}

.page-about .ab-filetypes span {
  font-size: .94rem;
  line-height: 1.65;
  color: var(--coal);
}

.page-about .ab-member li {
  padding: 14px 0;
  border-top: 1px solid rgba(247, 241, 231, .18);
  font-size: .94rem;
  line-height: 1.7;
  color: rgba(247, 241, 231, .84);
}

.page-about .ab-member li:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .ab-member__k {
  display: block;
  margin-bottom: 3px;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1rem;
  color: var(--paper);
}

.page-about .ab-lib__note {
  margin-top: clamp(24px, 3.4vw, 38px);
}

.page-about .ab-lib__note p {
  margin: 0;
  font-size: .95rem;
  line-height: 1.75;
  color: var(--coal);
}

/* ---------- 04 服务覆盖 ---------- */
.page-about .ab-cover {
  display: grid;
  gap: clamp(26px, 4vw, 50px);
  margin-top: clamp(28px, 4vw, 48px);
}

.page-about .ab-cover__fig {
  margin: 0;
}

.page-about .ab-cover__fig img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  object-fit: cover;
}

.page-about .ab-cover__copy p {
  margin: 0 0 18px;
  font-size: 1rem;
  line-height: 1.78;
  color: var(--coal);
}

.page-about .ab-regions {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .ab-regions li {
  display: grid;
  gap: 4px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--ab-line-soft);
}

.page-about .ab-regions li > span:last-child {
  font-size: .88rem;
  line-height: 1.62;
  color: var(--slate);
}

.page-about .ab-svc {
  display: grid;
  gap: clamp(16px, 2.4vw, 24px);
  margin-top: clamp(32px, 4.6vw, 56px);
}

.page-about .ab-svc__item {
  padding-top: 16px;
  border-top: 2px solid var(--ink);
}

.page-about .ab-svc__k {
  display: block;
  font-family: var(--mono);
  font-size: .76rem;
  letter-spacing: .16em;
  color: var(--gold);
  margin-bottom: 8px;
}

.page-about .ab-svc__item h3 {
  margin: 0 0 8px;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.06rem;
  color: var(--ink);
}

.page-about .ab-svc__item p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--coal);
}

/* ---------- 05 回访与原则 ---------- */
.page-about .ab-creed {
  list-style: none;
  margin: clamp(28px, 4vw, 46px) 0 0;
  padding: 0;
  display: grid;
  gap: clamp(20px, 3vw, 34px);
}

.page-about .ab-creed li {
  padding-left: clamp(16px, 2vw, 24px);
  border-left: 3px solid var(--gold-lit);
}

.page-about .ab-creed__word {
  display: block;
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(1.9rem, 5.4vw, 3.4rem);
  line-height: 1.05;
  color: var(--ink);
  margin-bottom: 10px;
  letter-spacing: .02em;
}

.page-about .ab-creed li p {
  margin: 0;
  font-size: .96rem;
  line-height: 1.72;
  color: var(--slate);
  max-width: 40ch;
}

.page-about .ab-roles {
  margin-top: clamp(30px, 4.4vw, 54px);
  display: grid;
  gap: 12px;
}

.page-about .ab-role {
  border-radius: var(--radius-sm);
  background: var(--paper-2);
  padding: 0 clamp(18px, 2.4vw, 26px);
}

.page-about .ab-role summary {
  cursor: pointer;
  list-style: none;
  padding: 18px 0;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.02rem;
  color: var(--ink);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

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

.page-about .ab-role summary::after {
  content: "+";
  flex: none;
  font-family: var(--mono);
  font-size: 1.1rem;
  color: var(--gold);
  line-height: 1;
}

.page-about .ab-role[open] summary::after {
  content: "−";
}

.page-about .ab-role summary:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
}

.page-about .ab-role ul {
  margin: 0;
  padding: 0 0 18px 1.1em;
  font-size: .94rem;
  line-height: 1.75;
  color: var(--coal);
}

.page-about .ab-role li {
  margin-bottom: .5em;
}

/* ---------- 06 长期记录 ---------- */
.page-about .ab-figures {
  display: grid;
  gap: clamp(18px, 2.6vw, 28px);
  margin-top: clamp(28px, 4vw, 46px);
}

.page-about .ab-figure {
  padding: clamp(18px, 2.4vw, 26px);
  background: var(--ink-2);
  border-radius: var(--radius-sm);
}

.page-about .ab-figure__n {
  display: block;
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(1.5rem, 3.2vw, 2.2rem);
  line-height: 1.1;
  color: var(--gold-lit);
}

.page-about .ab-figure__plus {
  font-size: .62em;
  margin-left: .12em;
}

.page-about .ab-figure__l {
  display: block;
  margin-top: 8px;
  font-size: .82rem;
  letter-spacing: .04em;
  color: rgba(247, 241, 231, .78);
}

.page-about .ab-record__text {
  margin: clamp(26px, 3.6vw, 42px) 0 0;
  max-width: 66ch;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--coal);
}

/* ---------- 收尾 ---------- */
.page-about .ab-cta__box {
  padding: clamp(28px, 4.4vw, 56px);
  border-radius: var(--radius);
  background: linear-gradient(140deg, var(--ink) 0%, var(--ink-2) 62%, #2a4a63 100%);
  position: relative;
  overflow: hidden;
}

.page-about .ab-cta__box::after {
  content: "";
  position: absolute;
  right: -70px;
  bottom: -90px;
  width: 260px;
  height: 260px;
  border-radius: 50%;
  border: 2px solid rgba(242, 184, 75, .28);
  pointer-events: none;
}

.page-about .ab-cta__box h2 {
  margin: 0 0 14px;
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(1.5rem, 3.4vw, 2.35rem);
  line-height: 1.25;
  color: var(--paper);
  max-width: 24ch;
}

.page-about .ab-cta__box p {
  margin: 0;
  max-width: 60ch;
  font-size: .97rem;
  line-height: 1.78;
  color: rgba(247, 241, 231, .82);
}

.page-about .ab-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 32px);
  position: relative;
  z-index: 1;
}

.page-about .ab-cta__actions .btn {
  min-height: 44px;
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .ab-regions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 22px;
  }

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

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

@media (min-width: 860px) {
  .page-about .ab-lanes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .ab-lib {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .ab-creed {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: clamp(20px, 3vw, 40px);
  }

  .page-about .ab-creed__word {
    font-size: clamp(1.7rem, 3.4vw, 2.6rem);
  }
}

@media (min-width: 940px) {
  .page-about .ab-dual__grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, .9fr);
    align-items: center;
  }

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

  .page-about .ab-tl-wrap {
    grid-template-columns: minmax(0, 1fr) 340px;
    align-items: start;
  }

  .page-about .ab-tl-fig {
    position: sticky;
    top: calc(var(--bar-h) + 28px);
  }

  .page-about .ab-svc {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .ab-figures {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 1180px) {
  .page-about .ab-hero__lede {
    font-size: 1.12rem;
  }

  .page-about .ab-tl-wrap {
    grid-template-columns: minmax(0, 1fr) 380px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-tl-fig {
    position: static;
  }
}
<<<END>>>