.page-about {
  --ab-rail: 208px;
  --ab-body-c: #383E48;
  color: var(--c-ink);
  font-family: var(--f-sans);
  padding-bottom: 64px;
}

/* ---------- 面包屑 ---------- */
.page-about .crumbs {
  padding-top: 20px;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .06em;
}

/* ---------- 首屏 ---------- */
.page-about .ab-masthead {
  display: grid;
  gap: 30px;
  padding: 26px 0 40px;
  border-bottom: 1px solid var(--c-line);
}

.page-about .ab-eyebrow {
  margin: 0;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--c-red);
}

.page-about .ab-h1 {
  margin: 14px 0 18px;
  font-family: var(--f-serif);
  font-weight: 300;
  font-size: clamp(30px, 6.6vw, 56px);
  line-height: 1.18;
  letter-spacing: .01em;
  color: var(--c-ink);
}

.page-about .ab-lede {
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ab-body-c);
  max-width: 38em;
}

.page-about .ab-figs {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 30px 0 0;
  background: var(--c-line);
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .ab-fig {
  background: var(--c-white);
  padding: 15px 16px 18px;
}

.page-about .ab-fig-k {
  margin: 0 0 8px;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--c-mute);
}

.page-about .ab-fig-v {
  margin: 0;
  font-family: var(--f-mono);
  font-size: 26px;
  line-height: 1.1;
  letter-spacing: .01em;
  color: var(--c-ink);
}

.page-about .ab-fig--now {
  background: var(--c-deep);
}

.page-about .ab-fig--now .ab-fig-k {
  color: rgba(255, 255, 255, .66);
}

.page-about .ab-fig--now .ab-fig-v {
  font-size: 36px;
  color: var(--c-gold);
}

.page-about .ab-masthead-fig {
  margin: 0;
  max-width: 300px;
}

.page-about .ab-masthead-fig img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border-radius: var(--r-xl);
  background: var(--c-mist);
  object-fit: cover;
}

.page-about .ab-masthead-fig figcaption {
  margin-top: 10px;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: .05em;
  line-height: 1.7;
  color: var(--c-mute);
}

/* ---------- 主体分栏 ---------- */
.page-about .ab-body {
  display: grid;
  gap: 0;
}

/* ---------- 左侧刻度栏 ---------- */
.page-about .ab-rail {
  padding: 26px 0 22px;
  border-bottom: 1px solid var(--c-line);
}

.page-about .ab-rail-group + .ab-rail-group {
  margin-top: 20px;
}

.page-about .ab-rail-title {
  margin: 0 0 12px;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--c-mute);
}

.page-about .ab-rail-list {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 4px;
  -webkit-overflow-scrolling: touch;
}

.page-about .ab-node {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border: 1px solid var(--c-line);
  border-radius: var(--pill);
  background: var(--c-white);
  color: var(--c-mute);
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .05em;
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease),
    background var(--dur) var(--ease);
}

.page-about .ab-node:hover {
  color: var(--c-turq);
  border-color: var(--c-turq);
}

.page-about .ab-node:focus-visible {
  outline: 2px solid var(--c-turq);
  outline-offset: 2px;
}

.page-about .ab-node--now {
  border-color: var(--c-red);
  color: var(--c-red);
  background: var(--c-red-08);
}

.page-about .ab-node-v {
  font-weight: 500;
}

.page-about .ab-node-t {
  font-size: 11px;
  opacity: .75;
}

.page-about .ab-rail-group--menu {
  display: none;
}

.page-about .ab-rail-menu {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-rail-menu a {
  display: block;
  padding: 7px 0 7px 14px;
  border-left: 2px solid var(--c-line);
  color: var(--c-mute);
  font-size: 13px;
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .ab-rail-menu a:hover {
  border-left-color: var(--c-turq);
  color: var(--c-turq);
}

.page-about .ab-rail-menu a:focus-visible {
  outline: 2px solid var(--c-turq);
  outline-offset: 2px;
}

/* ---------- 右侧叙事流 ---------- */
.page-about .ab-flow {
  padding-top: 4px;
}

.page-about .ab-sec {
  padding: 38px 0 42px;
  border-bottom: 1px solid var(--c-line);
}

.page-about .ab-sec:last-child {
  border-bottom: 0;
  padding-bottom: 12px;
}

.page-about .ab-sec-head {
  margin-bottom: 18px;
}

.page-about .ab-sec-index {
  margin: 0 0 10px;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--c-red);
}

.page-about .ab-sec-h2 {
  margin: 0 0 12px;
  font-family: var(--f-serif);
  font-weight: 400;
  font-size: clamp(23px, 4.4vw, 34px);
  line-height: 1.3;
  color: var(--c-ink);
}

.page-about .ab-sec-lede {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--c-mute);
  max-width: 38em;
}

.page-about .ab-p {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ab-body-c);
  max-width: 38em;
}

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

.page-about .ab-p a {
  color: var(--c-turq);
  text-decoration: none;
  border-bottom: 1px solid var(--c-turq-16);
  transition: border-color var(--dur) var(--ease);
}

.page-about .ab-p a:hover {
  border-bottom-color: var(--c-turq);
}

.page-about .ab-p a:focus-visible {
  outline: 2px solid var(--c-turq);
  outline-offset: 2px;
}

.page-about .ab-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
}

/* ---------- 插画带 ---------- */
.page-about .ab-band {
  margin: 24px 0 26px;
}

.page-about .ab-band img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border-radius: var(--r-lg);
  background: var(--c-mist);
  object-fit: cover;
}

.page-about .ab-band figcaption {
  margin-top: 10px;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: .05em;
  color: var(--c-mute);
}

.page-about .ab-band--team {
  margin: 26px 0 22px;
}

/* ---------- 版本时间轴 ---------- */
.page-about .ab-axis {
  list-style: none;
  margin: 0;
  padding: 0 0 0 22px;
  border-left: 1px solid var(--c-line);
}

.page-about .ab-step {
  position: relative;
  padding-bottom: 26px;
}

.page-about .ab-step::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--c-white);
  border: 1px solid var(--c-red);
}

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

.page-about .ab-step:last-child::before {
  background: var(--c-turq);
  border-color: var(--c-turq);
  box-shadow: 0 0 0 4px var(--c-turq-08);
}

.page-about .ab-step:target::before {
  background: var(--c-red);
  border-color: var(--c-red);
}

.page-about .ab-step-head {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 10px 12px;
  margin-bottom: 8px;
}

.page-about .ab-step-v {
  font-family: var(--f-mono);
  font-size: 15px;
  letter-spacing: .04em;
  color: var(--c-red);
}

.page-about .ab-h3 {
  margin: 0;
  font-family: var(--f-serif);
  font-weight: 400;
  font-size: 19px;
  line-height: 1.45;
  color: var(--c-ink);
}

.page-about .ab-points {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-points li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 8px;
  font-size: 14px;
  line-height: 1.72;
  color: var(--ab-body-c);
}

.page-about .ab-points li:last-child {
  margin-bottom: 0;
}

.page-about .ab-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .68em;
  width: 6px;
  height: 1px;
  background: var(--c-turq);
}

/* ---------- 折叠面板微调 ---------- */
.page-about .ab-fold {
  margin-top: 12px;
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
  background: var(--c-white);
  overflow: hidden;
}

.page-about .ab-fold .fold-head {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 11px 16px;
  background: var(--c-mist);
  border: 0;
  text-align: left;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--c-mute);
  cursor: pointer;
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .ab-fold .fold-head:hover {
  color: var(--c-turq);
}

.page-about .ab-fold .fold-head:focus-visible {
  outline: 2px solid var(--c-turq);
  outline-offset: -2px;
}

.page-about .ab-fold[data-open="true"] .fold-head {
  color: var(--c-turq);
  background: var(--c-turq-08);
}

.page-about .ab-fold .fold-inner {
  padding: 14px 16px 15px;
}

/* ---------- 数字来源 ---------- */
.page-about .ab-sources {
  margin: 0 0 20px;
  border-top: 1px solid var(--c-line);
}

.page-about .ab-source {
  display: grid;
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--c-line);
}

.page-about .ab-source dt {
  font-family: var(--f-mono);
  font-size: 13px;
  letter-spacing: .05em;
  color: var(--c-red);
}

.page-about .ab-source dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.76;
  color: var(--ab-body-c);
  max-width: 38em;
}

/* ---------- 团队分工 ---------- */
.page-about .ab-roster {
  display: grid;
  gap: 1px;
  background: var(--c-line);
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .ab-role {
  background: var(--c-white);
  padding: 16px 18px;
}

.page-about .ab-role-name {
  margin: 0 0 6px;
  font-family: var(--f-mono);
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--c-turq);
}

.page-about .ab-role-desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.74;
  color: var(--ab-body-c);
}

/* ---------- 出口 ---------- */
.page-about .ab-exit {
  margin-top: 30px;
  padding-top: 24px;
  border-top: 1px solid var(--c-line);
}

.page-about .ab-exit-title {
  margin: 0 0 14px;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--c-mute);
}

.page-about .ab-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .ab-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border: 1px solid var(--c-turq);
  border-radius: var(--pill);
  color: var(--c-turq);
  font-size: 14px;
  text-decoration: none;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .ab-pill:hover {
  background: var(--c-turq);
  color: var(--c-white);
}

.page-about .ab-pill:focus-visible {
  outline: 2px solid var(--c-turq);
  outline-offset: 2px;
}

/* ---------- 中等屏 ---------- */
@media (min-width: 700px) {
  .page-about .ab-figs {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .ab-role {
    display: grid;
    grid-template-columns: 112px minmax(0, 1fr);
    gap: 26px;
    align-items: baseline;
    padding: 18px 22px;
  }

  .page-about .ab-role-name {
    margin: 0;
  }

  .page-about .ab-source {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }
}

/* ---------- 桌面：左刻度 + 右叙事 ---------- */
@media (min-width: 1000px) {
  .page-about {
    padding-bottom: 88px;
  }

  .page-about .ab-masthead {
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: 64px;
    align-items: start;
    padding: 52px 0 60px;
  }

  .page-about .ab-masthead-fig {
    max-width: none;
    padding-top: 6px;
  }

  .page-about .ab-body {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    column-gap: 56px;
  }

  .page-about .ab-rail {
    position: sticky;
    top: calc(var(--topbar-h) + 20px);
    align-self: start;
    border-bottom: 0;
    border-right: 1px solid var(--c-line);
    padding: 44px 26px 32px 0;
    max-height: calc(100vh - var(--topbar-h) - 40px);
    overflow-y: auto;
  }

  .page-about .ab-rail-group--menu {
    display: block;
  }

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

  .page-about .ab-node {
    display: flex;
    width: 100%;
    justify-content: space-between;
    border: 0;
    border-left: 2px solid var(--c-line);
    border-radius: 0;
    background: transparent;
    padding: 9px 0 9px 14px;
  }

  .page-about .ab-node:hover {
    border-left-color: var(--c-turq);
    color: var(--c-turq);
  }

  .page-about .ab-node--now {
    border-left-color: var(--c-red);
    background: transparent;
    color: var(--c-turq);
  }

  .page-about .ab-node--now:hover {
    border-left-color: var(--c-turq);
  }

  .page-about .ab-sec {
    padding: 46px 0 52px;
  }

  .page-about .ab-sec:first-child {
    padding-top: 44px;
  }

  .page-about .ab-band img {
    max-height: 340px;
  }

  .page-about .ab-band--team img {
    max-height: 300px;
  }
}

/* ---------- 减弱动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .ab-node,
  .page-about .ab-pill,
  .page-about .ab-rail-menu a,
  .page-about .ab-fold .fold-head,
  .page-about .ab-p a {
    transition: none;
  }
}
<<<END>>>