.page-about {
  --ab-sec-pad: clamp(34px, 5vw, 68px);
  --ab-quiet: rgba(20, 22, 28, .74);
  --ab-grid-line: rgba(20, 22, 28, .07);
}

.page-about .by-crumbs {
  padding-top: clamp(14px, 2.4vw, 22px);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  margin-top: clamp(10px, 2vw, 18px);
  padding: clamp(26px, 4.6vw, 62px) 0 clamp(30px, 5vw, 68px);
  border-bottom: 2px solid var(--by-ink);
  background-image:
    linear-gradient(to right, var(--ab-grid-line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--ab-grid-line) 1px, transparent 1px);
  background-size: 52px 52px;
  background-position: center top;
}

.page-about .ab-hero__grid {
  display: grid;
  gap: clamp(22px, 3.6vw, 44px);
}

.page-about .ab-hero__title {
  margin: .28em 0 0;
  font-family: var(--by-font-cn);
  font-weight: 900;
  font-size: clamp(2.15rem, 6.6vw, 4.9rem);
  line-height: 1.04;
  letter-spacing: -.02em;
  color: var(--by-indigo);
}

.page-about .ab-hero__title em {
  font-style: normal;
  color: var(--by-ink);
  background-image: linear-gradient(transparent 64%, var(--by-amber-light) 64%);
  background-repeat: no-repeat;
  background-size: 100% 100%;
}

.page-about .ab-hero__lede {
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  max-width: 58ch;
  font-size: clamp(1rem, 1.5vw, 1.12rem);
  line-height: 1.85;
  color: var(--ab-quiet);
}

.page-about .ab-hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .ab-hero__sheet {
  border: 2px solid var(--by-ink);
  background: var(--by-paper);
  box-shadow: var(--by-shadow-card);
  padding: clamp(16px, 2.4vw, 24px);
}

.page-about .ab-hero__sheettitle {
  margin: 0 0 12px;
  font-family: var(--by-font-mono);
  font-size: .76rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--by-indigo);
}

.page-about .ab-hero__sheet .by-kv dd {
  font-family: var(--by-font-mono);
  font-weight: 700;
  color: var(--by-indigo);
}

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.7fr) minmax(0, .92fr);
    align-items: end;
  }
}

/* ---------- 正文骨架：目录 + 档案列 ---------- */
.page-about .ab-body {
  display: grid;
  gap: clamp(24px, 3.4vw, 44px);
  padding-top: clamp(28px, 4vw, 52px);
  padding-bottom: clamp(40px, 6vw, 80px);
}

.page-about .ab-toc {
  border-top: 2px solid var(--by-ink);
  padding-top: 12px;
}

.page-about .ab-toc__title {
  margin: 0 0 10px;
  font-family: var(--by-font-mono);
  font-size: .74rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--by-indigo);
}

.page-about .ab-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
}

.page-about .ab-toc__list a {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  font-size: .9rem;
  font-weight: 600;
  color: var(--by-ink);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color .2s var(--by-ease), border-color .2s var(--by-ease);
}

.page-about .ab-toc__list a:hover,
.page-about .ab-toc__list a:focus-visible {
  color: var(--by-indigo);
  border-bottom-color: var(--by-amber);
}

.page-about .ab-toc__n {
  font-family: var(--by-font-mono);
  font-size: .72rem;
  color: var(--by-celadon);
}

@media (min-width: 1024px) {
  .page-about .ab-body {
    grid-template-columns: 208px minmax(0, 1fr);
    gap: clamp(30px, 4vw, 62px);
  }
  .page-about .ab-toc {
    position: sticky;
    top: clamp(18px, 3vw, 34px);
    align-self: start;
  }
  .page-about .ab-toc__list {
    flex-direction: column;
    gap: 10px;
  }
}

/* ---------- 章节通用 ---------- */
.page-about .ab-sec {
  padding: var(--ab-sec-pad) 0;
  border-top: 1px solid var(--by-line);
}

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

.page-about .ab-note {
  margin: clamp(18px, 2.6vw, 26px) 0 0;
  padding: 14px 18px;
  border-left: 4px solid var(--by-celadon);
  background: var(--by-mist);
  font-size: .95rem;
  line-height: 1.8;
  color: var(--by-ink);
}

.page-about .ab-note--amber {
  border-left-color: var(--by-amber);
  background: rgba(243, 201, 119, .28);
}

.page-about .ab-inline-link {
  margin: clamp(16px, 2.4vw, 24px) 0 0;
}

/* ---------- 模块清单 ---------- */
.page-about .ab-modules {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--by-line);
  border: 1px solid var(--by-line-strong);
}

.page-about .ab-modules li {
  display: grid;
  gap: 4px;
  padding: 15px 17px;
  background: var(--by-paper);
}

.page-about .ab-modules li strong {
  font-size: 1rem;
  font-weight: 800;
  color: var(--by-indigo);
}

.page-about .ab-modules li span:last-child {
  font-size: .86rem;
  line-height: 1.7;
  color: var(--ab-quiet);
}

.page-about .ab-modules__n {
  font-family: var(--by-font-mono);
  font-size: .72rem;
  letter-spacing: .1em;
  color: var(--by-celadon);
}

@media (min-width: 700px) {
  .page-about .ab-modules {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 版本卡片 ---------- */
.page-about .ab-ver {
  display: grid;
  gap: 16px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .ab-ver__card {
  border: 2px solid var(--by-ink);
  background: var(--by-paper);
  box-shadow: var(--by-shadow-card);
  padding: clamp(18px, 2.6vw, 26px);
}

.page-about .ab-ver__card--pro {
  background: var(--by-indigo);
  border-color: var(--by-midnight);
  color: var(--by-paper);
  box-shadow: 8px 8px 0 rgba(14, 24, 56, .3);
}

.page-about .ab-ver__tag {
  display: inline-block;
  margin: 0 0 10px;
  padding: 3px 10px;
  font-family: var(--by-font-mono);
  font-size: .72rem;
  letter-spacing: .12em;
  background: var(--by-mist);
  color: var(--by-indigo);
}

.page-about .ab-ver__tag--amber {
  background: var(--by-amber);
  color: var(--by-midnight);
}

.page-about .ab-ver__name {
  margin: 0 0 6px;
  font-size: clamp(1.15rem, 2.1vw, 1.4rem);
  font-weight: 900;
  letter-spacing: -.01em;
}

.page-about .ab-ver__fit {
  margin: 0 0 14px;
  font-size: .86rem;
  line-height: 1.7;
  color: var(--ab-quiet);
}

.page-about .ab-ver__card--pro .ab-ver__fit {
  color: rgba(247, 244, 237, .78);
}

.page-about .ab-ver__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 9px;
}

.page-about .ab-ver__list li {
  position: relative;
  padding-left: 18px;
  font-size: .92rem;
  line-height: 1.72;
}

.page-about .ab-ver__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .68em;
  width: 7px;
  height: 7px;
  background: var(--by-celadon);
}

.page-about .ab-ver__card--pro .ab-ver__list li::before {
  background: var(--by-amber-light);
}

@media (min-width: 820px) {
  .page-about .ab-ver {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }
}

/* ---------- 图片 ---------- */
.page-about .ab-tlfig,
.page-about .ab-teamfig,
.page-about .ab-mapfig {
  margin: clamp(20px, 3vw, 30px) 0 0;
}

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

/* ---------- 时间轴 ---------- */
.page-about .ab-tl {
  margin-top: clamp(22px, 3.2vw, 32px);
}

.page-about .ab-tl .by-acc__item {
  position: relative;
  border-left: 2px solid var(--by-mist);
  padding-left: 24px;
  padding-bottom: 4px;
}

.page-about .ab-tl .by-acc__item::before {
  content: "";
  position: absolute;
  left: -8px;
  top: 17px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--by-celadon);
  border: 3px solid var(--by-paper);
  box-sizing: content-box;
}

.page-about .ab-tl .by-acc__item:last-child {
  border-left-color: transparent;
}

.page-about .ab-tl .by-acc__trigger {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 12px;
  width: 100%;
  padding: 12px 0;
  border: 0;
  background: none;
  text-align: left;
  cursor: pointer;
  font-family: var(--by-font-cn);
  color: var(--by-ink);
}

.page-about .ab-tl .by-acc__trigger:hover .ab-tl__label,
.page-about .ab-tl .by-acc__trigger:focus-visible .ab-tl__label {
  color: var(--by-indigo);
  text-decoration: underline;
  text-decoration-color: var(--by-amber);
  text-underline-offset: 4px;
}

.page-about .ab-tl__year {
  font-family: var(--by-font-mono);
  font-size: .82rem;
  font-weight: 700;
  padding: 3px 9px;
  background: var(--by-amber-light);
  color: var(--by-midnight);
}

.page-about .ab-tl__label {
  font-size: clamp(1rem, 1.6vw, 1.16rem);
  font-weight: 800;
  line-height: 1.4;
}

.page-about .ab-tl .by-acc__panel {
  padding: 0 0 14px;
  font-size: .93rem;
  line-height: 1.8;
  color: var(--ab-quiet);
}

.page-about .ab-tl .by-acc__panel p {
  margin: 0;
}

/* ---------- 团队 ---------- */
.page-about .ab-sec--team {
  padding-left: 0;
  padding-right: 0;
}

.page-about .ab-team {
  position: relative;
  background: var(--by-indigo);
  color: var(--by-paper);
  padding: clamp(22px, 4vw, 46px);
  border: 2px solid var(--by-midnight);
  box-shadow: 8px 8px 0 rgba(27, 42, 91, .22);
  background-image:
    linear-gradient(to right, rgba(168, 203, 191, .12) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(168, 203, 191, .12) 1px, transparent 1px);
  background-size: 44px 44px;
}

.page-about .ab-team .by-section__title {
  color: var(--by-paper);
}

.page-about .ab-eyebrow--light {
  color: var(--by-amber-light);
}

.page-about .ab-team .by-lede {
  color: rgba(247, 244, 237, .82);
}

.page-about .ab-teamfig .by-figure__caption {
  color: rgba(247, 244, 237, .72);
}

.page-about .ab-roles {
  display: grid;
  gap: 14px;
  margin-top: clamp(18px, 2.8vw, 26px);
}

.page-about .ab-role {
  background: var(--by-paper);
  color: var(--by-ink);
  border: 2px solid var(--by-midnight);
  padding: 16px 18px 18px;
  box-shadow: 6px 6px 0 rgba(14, 24, 56, .34);
  transition: transform .24s var(--by-ease), box-shadow .24s var(--by-ease), border-color .24s var(--by-ease);
}

.page-about .ab-role:hover,
.page-about .ab-role:focus-within {
  transform: translate(-3px, -3px);
  border-color: var(--by-amber);
  box-shadow: 9px 9px 0 rgba(14, 24, 56, .4);
}

.page-about .ab-role__code {
  margin: 0;
  display: inline-block;
  font-family: var(--by-font-mono);
  font-size: .7rem;
  letter-spacing: .12em;
  padding: 2px 8px;
  background: var(--by-amber-light);
  color: var(--by-midnight);
}

.page-about .ab-role__num {
  margin: 10px 0 0;
  font-family: var(--by-font-mono);
  font-weight: 700;
  font-size: clamp(1.9rem, 4vw, 2.5rem);
  line-height: 1;
  color: var(--by-indigo);
}

.page-about .ab-role__name {
  margin: 4px 0 8px;
  font-size: 1.12rem;
  font-weight: 900;
  color: var(--by-ink);
}

.page-about .ab-role__when {
  margin: 0 0 10px;
  padding-bottom: 10px;
  border-bottom: 1px dashed var(--by-line-strong);
  font-size: .82rem;
  line-height: 1.7;
  color: var(--by-celadon);
}

.page-about .ab-role__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 7px;
}

.page-about .ab-role__list li {
  position: relative;
  padding-left: 14px;
  font-size: .86rem;
  line-height: 1.72;
  color: var(--ab-quiet);
}

.page-about .ab-role__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .66em;
  width: 5px;
  height: 5px;
  background: var(--by-amber);
}

.page-about .ab-team__foot {
  margin: clamp(16px, 2.4vw, 22px) 0 0;
  font-size: .88rem;
  line-height: 1.75;
  color: rgba(247, 244, 237, .82);
}

@media (min-width: 780px) {
  .page-about .ab-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 流程折叠 ---------- */
.page-about .ab-flow {
  margin-top: clamp(20px, 3vw, 28px);
  border-top: 1px solid var(--by-line-strong);
}

.page-about .ab-flow .by-acc__item {
  border-bottom: 1px solid var(--by-line);
}

.page-about .ab-flow .by-acc__trigger {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 14px;
  width: 100%;
  padding: 15px 2px;
  border: 0;
  background: none;
  text-align: left;
  cursor: pointer;
  font-family: var(--by-font-cn);
  color: var(--by-ink);
  transition: background-color .2s var(--by-ease);
}

.page-about .ab-flow .by-acc__trigger:hover,
.page-about .ab-flow .by-acc__trigger:focus-visible {
  background: rgba(168, 203, 191, .18);
}

.page-about .ab-flow__n {
  font-family: var(--by-font-mono);
  font-size: .82rem;
  font-weight: 700;
  color: var(--by-celadon);
}

.page-about .ab-flow__label {
  font-size: clamp(1rem, 1.6vw, 1.14rem);
  font-weight: 800;
}

.page-about .ab-flow .by-acc__panel {
  padding: 0 2px 16px 34px;
  font-size: .92rem;
  line-height: 1.8;
  color: var(--ab-quiet);
}

.page-about .ab-flow .by-acc__panel p {
  margin: 0;
}

/* ---------- 数据条 ---------- */
.page-about .ab-metrics {
  display: grid;
  gap: 1px;
  margin-top: clamp(22px, 3.2vw, 32px);
  background: var(--by-line-strong);
  border: 2px solid var(--by-ink);
}

.page-about .ab-metric {
  display: grid;
  gap: 4px;
  padding: 16px 18px;
  background: var(--by-paper);
}

.page-about .ab-metric__n {
  font-family: var(--by-font-mono);
  font-size: clamp(1.7rem, 3.4vw, 2.2rem);
  font-weight: 700;
  line-height: 1;
  color: var(--by-indigo);
}

.page-about .ab-metric__l {
  font-size: .84rem;
  line-height: 1.65;
  color: var(--ab-quiet);
}

@media (min-width: 640px) {
  .page-about .ab-metrics {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 980px) {
  .page-about .ab-metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* ---------- 联系 ---------- */
.page-about .ab-contact {
  display: grid;
  gap: 16px;
  margin-top: clamp(22px, 3.2vw, 32px);
}

.page-about .ab-contact__info {
  border: 2px solid var(--by-ink);
  background: var(--by-mist);
  padding: clamp(18px, 2.6vw, 26px);
}

.page-about .ab-contact__title {
  margin: 0 0 12px;
  font-size: clamp(1.1rem, 2vw, 1.3rem);
  font-weight: 900;
  color: var(--by-indigo);
}

.page-about .ab-contact__info .by-kv dd {
  font-family: var(--by-font-mono);
  font-weight: 600;
}

.page-about .ab-contact__note {
  margin: 14px 0 0;
  padding-top: 12px;
  border-top: 1px dashed var(--by-line-strong);
  font-size: .84rem;
  line-height: 1.75;
  color: var(--ab-quiet);
}

.page-about .ab-contact__go {
  border: 2px solid var(--by-indigo);
  background: var(--by-paper);
  padding: clamp(18px, 2.6vw, 26px);
  box-shadow: var(--by-shadow-card);
}

.page-about .ab-contact__gotitle {
  margin: 0 0 12px;
  font-family: var(--by-font-mono);
  font-size: .74rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--by-indigo);
}

.page-about .ab-contact__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .ab-contact__list a {
  display: block;
  padding-left: 18px;
  position: relative;
  font-size: .94rem;
  font-weight: 600;
  line-height: 1.7;
  color: var(--by-ink);
  text-decoration: none;
  border-bottom: 1px solid var(--by-line);
  padding-bottom: 8px;
  transition: color .2s var(--by-ease);
}

.page-about .ab-contact__list a::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 7px;
  height: 7px;
  background: var(--by-amber);
}

.page-about .ab-contact__list a:hover,
.page-about .ab-contact__list a:focus-visible {
  color: var(--by-indigo);
}

@media (min-width: 860px) {
  .page-about .ab-contact {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    gap: 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-role,
  .page-about .ab-role:hover,
  .page-about .ab-role:focus-within {
    transform: none;
    transition: none;
  }
}
<<<END>>>