.page-about {
  --ab-rail-w: 236px;
  --ab-gap: 56px;
  color: var(--text);
  padding: 96px 0 88px;
}

.page-about .ab-shell {
  width: min(calc(100% - (var(--gutter) * 2)), var(--maxw));
  margin-inline: auto;
}

/* ---------- 面包屑 ---------- */
.page-about .ab-crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .ab-crumbs a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--speed) var(--ease), border-color var(--speed) var(--ease);
}

.page-about .ab-crumbs a:hover,
.page-about .ab-crumbs a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .ab-crumbs__sep {
  color: var(--line);
}

.page-about .ab-crumbs__here {
  color: var(--cyan-deep);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  display: grid;
  gap: 28px;
  padding: 8px 0 0;
}

.page-about .ab-eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .ab-eyebrow::before {
  content: "";
  width: 30px;
  height: 2px;
  background: var(--cyan-deep);
  flex: none;
}

.page-about .ab-hero h1 {
  margin: 0 0 20px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(30px, 7vw, 56px);
  line-height: 1.07;
  letter-spacing: -0.02em;
  color: var(--text);
}

.page-about .ab-hl {
  color: var(--cyan);
  background-image: linear-gradient(transparent 64%, rgba(123, 247, 208, 0.18) 64%);
}

.page-about .ab-hero__lead {
  margin: 0 0 28px;
  max-width: 56ch;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--muted);
}

.page-about .ab-hero__stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .ab-hero__stat {
  background: var(--night-2);
  padding: 15px 14px;
}

.page-about .ab-hero__num {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 29px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-hero__unit {
  font-size: 14px;
  letter-spacing: 0;
  margin-left: 2px;
  color: var(--cyan-deep);
}

.page-about .ab-hero__cap {
  margin: 9px 0 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--muted);
}

.page-about .ab-hero__media {
  position: relative;
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--night-2);
}

.page-about .ab-hero__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 5;
  object-fit: cover;
}

.page-about .ab-hero__media figcaption {
  position: absolute;
  left: 0;
  bottom: 0;
  right: 0;
  padding: 26px 16px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--cyan);
  background: linear-gradient(transparent, rgba(5, 20, 15, 0.9));
}

/* ---------- 研究板骨架 ---------- */
.page-about .ab-board {
  margin-top: 64px;
  display: grid;
  gap: 36px;
}

.page-about .ab-rail {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--night-2);
  padding: 18px 16px;
}

.page-about .ab-rail__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .ab-rail__list {
  list-style: none;
  margin: 0 0 20px;
  padding: 0 0 4px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .ab-rail__list li {
  flex: none;
}

.page-about .ab-rail__list a {
  display: block;
  padding: 7px 13px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  font-size: 12.5px;
  color: var(--muted);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--speed) var(--ease), border-color var(--speed) var(--ease), background var(--speed) var(--ease);
}

.page-about .ab-rail__list a:hover,
.page-about .ab-rail__list a:focus-visible {
  color: var(--night);
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .ab-rail__figures {
  border-top: 1px solid var(--line);
  padding-top: 16px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px 16px;
}

.page-about .ab-rail__figures .ab-rail__title {
  grid-column: 1 / -1;
  margin-bottom: 0;
}

.page-about .ab-rail__fig {
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .ab-rail__fig b {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 24px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan-deep);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-rail__fig span {
  font-size: 11.5px;
  line-height: 1.5;
  color: var(--muted);
}

/* ---------- 章节流 ---------- */
.page-about .ab-flow {
  display: flex;
  flex-direction: column;
  gap: 62px;
}

.page-about .ab-sec {
  position: relative;
  scroll-margin-top: 104px;
}

.page-about .ab-sec__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 20px;
}

.page-about .ab-sec__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--cyan-deep);
}

.page-about .ab-sec__head h2 {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(21px, 4.2vw, 32px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .ab-sum {
  margin: 0 0 22px;
  padding: 10px 14px;
  border-left: 2px solid var(--cyan-deep);
  border-radius: 0 10px 10px 0;
  background: linear-gradient(90deg, rgba(47, 224, 174, 0.11), rgba(47, 224, 174, 0));
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-body p {
  margin: 0 0 16px;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--text);
}

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

.page-about .ab-body--after {
  margin-top: 26px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.page-about .ab-h3 {
  margin: 24px 0 10px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 16px;
  line-height: 1.4;
  color: var(--cyan);
}

.page-about .ab-body a {
  color: var(--text);
  text-decoration: none;
  background-image: linear-gradient(var(--cyan-deep), var(--cyan-deep));
  background-repeat: no-repeat;
  background-position: 50% 100%;
  background-size: 0% 1px;
  transition: background-size var(--speed) var(--ease), color var(--speed) var(--ease);
}

.page-about .ab-body a:hover,
.page-about .ab-body a:focus-visible {
  color: var(--cyan);
  background-size: 100% 1px;
}

/* ---------- 时间线 ---------- */
.page-about .ab-tl {
  list-style: none;
  margin: 0;
  padding: 0 0 0 26px;
  position: relative;
}

.page-about .ab-tl::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--cyan-deep), rgba(47, 224, 174, 0.05));
}

.page-about .ab-tl__item {
  position: relative;
  padding-bottom: 18px;
}

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

.page-about .ab-tl__item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 20px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--night);
  border: 2px solid var(--cyan-deep);
  box-shadow: 0 0 0 5px rgba(47, 224, 174, 0.08);
  transition: box-shadow var(--speed) var(--ease), border-color var(--speed) var(--ease);
}

.page-about .ab-tl__item:hover::before {
  border-color: var(--cyan);
  box-shadow: 0 0 0 7px rgba(47, 224, 174, 0.16);
}

.page-about .ab-tl__card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 20px;
  transition: border-color var(--speed) var(--ease), transform var(--speed) var(--ease);
}

.page-about .ab-tl__item:hover .ab-tl__card {
  border-color: var(--cyan);
  transform: translateY(-2px);
}

.page-about .ab-tl__ver {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .ab-tl__card h3 {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17.5px;
  line-height: 1.35;
  color: var(--text);
}

.page-about .ab-tl__card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text);
}

.page-about .ab-tl__card .ab-tl__extra {
  margin-top: 12px;
  padding-top: 11px;
  border-top: 1px dashed var(--line);
  font-size: 13px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 图文分栏 ---------- */
.page-about .ab-split {
  display: grid;
  gap: 24px;
}

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

.page-about .ab-fig img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  object-fit: cover;
}

.page-about .ab-fig--dim img {
  filter: saturate(0.82) brightness(0.9);
}

.page-about .ab-fig figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  line-height: 1.6;
  color: var(--muted);
}

/* ---------- 折叠数据说明 ---------- */
.page-about .ab-details {
  margin-top: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  overflow: hidden;
}

.page-about .ab-details summary {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 15px 18px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.03em;
  color: var(--cyan);
  transition: background var(--speed) var(--ease);
}

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

.page-about .ab-details summary::before {
  content: "+";
  flex: none;
  font-size: 16px;
  line-height: 1;
  color: var(--cyan-deep);
}

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

.page-about .ab-details summary:hover,
.page-about .ab-details summary:focus-visible {
  background: rgba(28, 70, 56, 0.55);
}

.page-about .ab-details__body {
  padding: 16px 18px 20px;
  border-top: 1px solid var(--line);
}

.page-about .ab-details__body p {
  margin: 0 0 14px;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .ab-fields {
  list-style: none;
  margin: 0 0 14px;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .ab-fields li {
  padding: 5px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: var(--night-2);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-details__foot {
  margin: 0;
  font-size: 13px;
  color: var(--muted);
}

.page-about .ab-details__foot a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(123, 247, 208, 0.4);
}

.page-about .ab-details__foot a:hover {
  border-bottom-color: var(--cyan);
}

/* ---------- 覆盖范围卡片 ---------- */
.page-about .ab-cov {
  display: grid;
  gap: 14px;
}

.page-about .ab-cov__item {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--night-2);
  transition: border-color var(--speed) var(--ease), transform var(--speed) var(--ease);
}

.page-about .ab-cov__item:hover {
  border-color: var(--cyan);
  transform: translateY(-2px);
}

.page-about .ab-cov__num {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 34px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .ab-cov__item h3 {
  margin: 12px 0 9px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 15.5px;
  line-height: 1.45;
  color: var(--text);
}

.page-about .ab-cov__item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 生态清单 ---------- */
.page-about .ab-eco {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .ab-eco li {
  padding: 17px 0;
  border-bottom: 1px solid var(--line);
  display: grid;
  gap: 6px;
}

.page-about .ab-eco__k {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--amber);
}

.page-about .ab-eco__v {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text);
}

/* ---------- 加入与共创 ---------- */
.page-about .ab-join {
  padding: 24px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    radial-gradient(120% 130% at 100% 0%, rgba(47, 224, 174, 0.15), transparent 62%),
    var(--night-2);
}

.page-about .ab-join__body p {
  margin: 0 0 14px;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--text);
}

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

.page-about .ab-join__contact {
  margin: 22px 0 0;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.page-about .ab-join__line {
  margin: 0 0 10px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: baseline;
}

.page-about .ab-join__k {
  flex: none;
  min-width: 44px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.page-about .ab-join__v {
  font-family: var(--font-mono);
  font-size: 13.5px;
  color: var(--cyan);
  word-break: break-word;
}

.page-about .ab-join__actions {
  margin-top: 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .ab-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 11px 22px;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  font-size: 14px;
  text-decoration: none;
  transition: background var(--speed) var(--ease), color var(--speed) var(--ease), border-color var(--speed) var(--ease);
}

.page-about .ab-btn--solid {
  background: var(--cyan);
  color: var(--night);
  font-weight: 700;
}

.page-about .ab-btn--solid:hover,
.page-about .ab-btn--solid:focus-visible {
  background: var(--cyan-deep);
}

.page-about .ab-btn--ghost {
  border-color: var(--line);
  color: var(--text);
}

.page-about .ab-btn--ghost:hover,
.page-about .ab-btn--ghost:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
}

/* ---------- 返回顶部 ---------- */
.page-about .ab-top {
  position: fixed;
  right: 16px;
  bottom: 16px;
  z-index: 30;
  padding: 10px 16px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line);
  background: rgba(10, 35, 28, 0.92);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: border-color var(--speed) var(--ease), color var(--speed) var(--ease);
}

.page-about .ab-top:hover,
.page-about .ab-top:focus-visible {
  border-color: var(--cyan);
}

/* ---------- 竖排批注 ---------- */
.page-about .ab-sec::after {
  display: none;
}

/* ---------- 断点 ---------- */
@media (min-width: 620px) {
  .page-about .ab-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 860px) {
  .page-about .ab-split {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 32px;
    align-items: start;
  }

  .page-about .ab-split--media-right {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }

  .page-about .ab-hero {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 44px;
    align-items: end;
    padding-top: 24px;
  }

  .page-about .ab-hero__media img {
    aspect-ratio: 4 / 5;
    max-height: 560px;
  }

  .page-about .ab-eco li {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }

  .page-about .ab-join {
    padding: 30px 28px;
  }
}

@media (min-width: 1000px) {
  .page-about .ab-board {
    grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
    gap: var(--ab-gap);
    align-items: start;
  }

  .page-about .ab-rail {
    position: sticky;
    top: 96px;
    padding: 20px 18px;
  }

  .page-about .ab-rail__list {
    display: block;
    overflow: visible;
    margin-bottom: 22px;
  }

  .page-about .ab-rail__list li + li {
    margin-top: 2px;
  }

  .page-about .ab-rail__list a {
    border: 0;
    border-left: 2px solid var(--line);
    border-radius: 0;
    padding: 7px 0 7px 14px;
    white-space: normal;
    background: none;
    line-height: 1.5;
  }

  .page-about .ab-rail__list a:hover,
  .page-about .ab-rail__list a:focus-visible {
    background: none;
    color: var(--text);
    border-left-color: var(--cyan);
  }

  .page-about .ab-rail__figures {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }

  .page-about .ab-rail__fig {
    flex-direction: row;
    align-items: baseline;
    gap: 10px;
  }

  .page-about .ab-rail__fig b {
    font-size: 21px;
    flex: none;
  }

  .page-about .ab-flow {
    gap: 76px;
  }
}

@media (min-width: 1180px) {
  .page-about .ab-sec::after {
    display: block;
    content: attr(data-annotation);
    position: absolute;
    left: -46px;
    top: 4px;
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 10.5px;
    letter-spacing: 0.34em;
    text-transform: uppercase;
    color: var(--line);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-tl__card,
  .page-about .ab-cov__item,
  .page-about .ab-tl__item::before,
  .page-about .ab-btn,
  .page-about .ab-body a,
  .page-about .ab-rail__list a,
  .page-about .ab-crumbs a,
  .page-about .ab-top {
    transition: none;
  }

  .page-about .ab-tl__item:hover .ab-tl__card,
  .page-about .ab-cov__item:hover {
    transform: none;
  }
}