.page-about {
  --ab-line-soft: rgba(31, 62, 99, .55);
  --ab-ink-soft: rgba(26, 20, 16, .32);
  display: block;
}

/* ── 首屏 ───────────────────────────────── */
.page-about .ab-hero {
  position: relative;
  padding: 26px 0 34px;
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 20px;
  right: 20px;
  height: 3px;
  background: linear-gradient(90deg, var(--cyan) 0 18%, var(--orange) 18% 30%, var(--line) 30% 100%);
}

.page-about .ab-kicker {
  color: var(--cyan);
  margin: 0 0 12px;
}

.page-about .ab-hero__title {
  margin: 0 0 10px;
  font-size: 30px;
  line-height: 1.16;
  letter-spacing: -.02em;
  font-weight: 800;
  max-width: 640px;
}

.page-about .ab-hero__stripe {
  display: block;
  width: 88px;
  height: 6px;
  background: var(--orange);
  transform: skewX(-28deg);
  margin: 0 0 18px;
}

.page-about .ab-lead {
  margin: 12px 0 0;
  max-width: 64ch;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.75;
}

.page-about .ab-hero__lede {
  color: rgba(230, 237, 248, .84);
  margin-top: 0;
}

.page-about .ab-stats {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-soft, var(--line));
  border: 1px solid var(--line);
}

.page-about .ab-stats li {
  background: var(--ink);
  padding: 14px 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .ab-stats__v {
  font-size: 24px;
  font-weight: 800;
  color: var(--cyan);
  letter-spacing: -.02em;
  line-height: 1.1;
}

.page-about .ab-stats__u {
  font-size: 12px;
  color: var(--muted);
  margin-left: 3px;
  letter-spacing: 0;
}

.page-about .ab-stats__k {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--muted);
  text-transform: uppercase;
}

/* ── 章节基础 ───────────────────────────── */
.page-about .ab-block {
  padding: 34px 0;
  border-top: 1px solid var(--ab-line-soft);
}

.page-about .ab-block:first-of-type {
  border-top: 0;
}

.page-about .section__head .ab-lead {
  margin-top: 10px;
}

.page-about .ab-figure {
  margin: 24px 0 0;
}

.page-about .ab-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* ── 时间轴 ─────────────────────────────── */
.page-about .ab-timeline {
  list-style: none;
  margin: 26px 0 0;
  padding: 0 0 0 28px;
  position: relative;
  display: grid;
  gap: 18px;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), var(--line) 85%);
}

.page-about .ab-stage {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  padding: 18px 16px 20px;
}

.page-about .ab-stage::before {
  content: "";
  position: absolute;
  left: -25px;
  top: 22px;
  width: 11px;
  height: 11px;
  border: 2px solid var(--cyan);
  background: var(--ink);
  border-radius: 50%;
}

.page-about .ab-stage__idx {
  color: var(--cyan);
  margin: 0 0 8px;
}

.page-about .ab-stage__title {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -.01em;
  line-height: 1.4;
}

.page-about .ab-stage__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(230, 237, 248, .84);
}

.page-about .ab-stage__foot {
  margin: 14px 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

/* ── 数据流程 ───────────────────────────── */
.page-about .ab-pipeline {
  margin-top: 24px;
  display: grid;
  gap: 24px;
}

.page-about .ab-figure--flow {
  margin: 0;
}

.page-about .ab-flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .ab-flow__node {
  position: relative;
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr);
  gap: 14px;
  align-items: start;
}

.page-about .ab-flow__node::before {
  content: "";
  position: absolute;
  left: 13px;
  top: 30px;
  bottom: -14px;
  width: 1px;
  background: var(--line);
}

.page-about .ab-flow__node:last-child::before {
  display: none;
}

.page-about .ab-flow__dot {
  width: 27px;
  height: 27px;
  display: grid;
  place-items: center;
  font-size: 11px;
  color: var(--cyan);
  background: var(--ink);
  border: 2px solid var(--cyan);
  border-radius: 50%;
}

.page-about .ab-flow__body {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 15px 15px 17px;
  transition: border-color .18s var(--ease), transform .18s var(--ease);
}

.page-about .ab-flow__node:hover .ab-flow__body,
.page-about .ab-flow__node:focus-within .ab-flow__body {
  border-color: var(--cyan);
  transform: translateY(-2px);
}

.page-about .ab-flow__idx {
  color: var(--muted);
  margin: 0 0 6px;
}

.page-about .ab-flow__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -.01em;
}

.page-about .ab-flow__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: rgba(230, 237, 248, .84);
}

.page-about .ab-flow__meta {
  margin: 12px 0 0;
  padding-top: 10px;
  border-top: 1px dashed var(--line);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--muted);
}

/* ── 纸白归档面板 ───────────────────────── */
.page-about .ab-paper {
  padding: 24px 20px 26px;
}

.page-about .ab-paper .ab-kicker {
  color: var(--paper-ink);
  opacity: .6;
}

.page-about .ab-paper__title {
  color: var(--paper-ink);
  margin: 6px 0 14px;
}

.page-about .ab-paper__lede {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(26, 20, 16, .86);
}

.page-about .ab-summary {
  margin-top: 22px;
  display: grid;
  gap: 0;
}

.page-about .ab-summary__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 13px 0;
  border-top: 1px solid var(--ab-ink-soft);
}

.page-about .ab-summary__row:last-child {
  border-bottom: 1px solid var(--ab-ink-soft);
}

.page-about .ab-summary__ver {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .08em;
  color: var(--paper-ink);
  background: rgba(255, 106, 43, .22);
  justify-self: start;
  padding: 3px 10px;
  border: 1px solid var(--paper-ink);
}

.page-about .ab-summary__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(26, 20, 16, .86);
}

.page-about .ab-paper__foot {
  margin: 20px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(26, 20, 16, .86);
}

.page-about .ab-paper__link {
  color: var(--paper-ink);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
  font-weight: 700;
}

.page-about .ab-paper__link:hover,
.page-about .ab-paper__link:focus-visible {
  background: var(--orange);
  text-decoration-color: var(--orange);
}

/* ── 团队与覆盖 ─────────────────────────── */
.page-about .ab-team {
  margin-top: 24px;
}

.page-about .ab-team__grid {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.page-about .ab-fact {
  padding: 16px 16px 18px;
}

.page-about .ab-fact__v {
  margin: 0;
  font-size: 30px;
  font-weight: 800;
  color: var(--cyan);
  letter-spacing: -.02em;
  line-height: 1;
}

.page-about .ab-fact__u {
  font-size: 16px;
  color: var(--orange);
  margin-left: 2px;
}

.page-about .ab-fact__t {
  margin: 10px 0 6px;
  font-size: 16px;
  font-weight: 700;
}

.page-about .ab-fact__d {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .ab-matrix {
  margin: 22px 0 0;
  position: relative;
  border: 3px solid var(--paper-ink);
  box-shadow: var(--shadow-hard);
  background: var(--panel);
  overflow: hidden;
}

.page-about .ab-matrix img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ab-matrix__cap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 16px;
  padding: 11px 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--muted);
  border-top: 1px solid var(--line);
  background: var(--ink);
}

.page-about .ab-matrix__dot {
  display: inline-block;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  margin-right: 6px;
}

.page-about .ab-matrix__dot--cyan {
  background: var(--cyan);
}

.page-about .ab-matrix__dot--orange {
  background: var(--orange);
}

.page-about .ab-local {
  margin-top: 18px;
  padding: 18px 16px 20px;
  border: 1px solid var(--orange);
  background: linear-gradient(180deg, rgba(255, 106, 43, .14), rgba(255, 106, 43, .03));
  border-left-width: 5px;
}

.page-about .ab-local__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -.01em;
}

.page-about .ab-local__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(230, 237, 248, .86);
}

/* ── 合作生态 ───────────────────────────── */
.page-about .ab-coop {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .ab-coop__item {
  position: relative;
  padding: 20px 18px 22px 20px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-top: 3px solid var(--orange);
}

.page-about .ab-coop__idx {
  color: var(--orange);
  margin: 0 0 8px;
}

.page-about .ab-coop__title {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -.01em;
}

.page-about .ab-coop__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(230, 237, 248, .84);
}

.page-about .ab-rhythm {
  margin-top: 20px;
  padding: 16px 18px;
  background: rgba(61, 214, 140, .08);
  border: 1px dashed rgba(61, 214, 140, .5);
}

.page-about .ab-rhythm__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(230, 237, 248, .86);
}

.page-about .ab-rhythm__link {
  color: var(--green);
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .ab-rhythm__link:hover,
.page-about .ab-rhythm__link:focus-visible {
  color: var(--ink);
  background: var(--green);
}

/* ── 后续入口 ───────────────────────────── */
.page-about .ab-next {
  padding-bottom: 46px;
}

.page-about .ab-next__title {
  margin: 0 0 18px;
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -.01em;
}

.page-about .ab-next__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-next__a {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 15px 16px;
  background: var(--ink);
  color: var(--text);
  text-decoration: none;
  font-size: 15px;
  line-height: 1.6;
  transition: background .16s var(--ease), color .16s var(--ease);
}

.page-about .ab-next__a:hover,
.page-about .ab-next__a:focus-visible {
  background: var(--panel);
  color: var(--cyan);
}

.page-about .ab-next__n {
  color: var(--orange);
  font-size: 12px;
  letter-spacing: .08em;
  flex: none;
}

/* ── 桌面端 ─────────────────────────────── */
@media (min-width: 760px) {
  .page-about .ab-hero {
    padding: 40px 0 44px;
  }

  .page-about .ab-hero__title {
    font-size: 44px;
    max-width: 720px;
  }

  .page-about .ab-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    margin-top: 34px;
  }

  .page-about .ab-stats__v {
    font-size: 30px;
  }

  .page-about .ab-block {
    padding: 56px 0;
  }

  .page-about .ab-summary__row {
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 18px;
    align-items: baseline;
    padding: 15px 0;
  }

  .page-about .ab-coop {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

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

@media (min-width: 1020px) {
  .page-about .ab-timeline {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
    padding: 30px 0 0;
  }

  .page-about .ab-timeline::before {
    left: 0;
    right: 0;
    top: 14px;
    bottom: auto;
    width: auto;
    height: 1px;
    background: linear-gradient(90deg, var(--cyan), var(--line) 82%);
  }

  .page-about .ab-stage {
    border-left: 1px solid var(--line);
    border-top: 3px solid var(--cyan);
  }

  .page-about .ab-stage::before {
    left: 20px;
    top: -20px;
  }

  .page-about .ab-pipeline {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 32px;
    align-items: start;
  }

  .page-about .ab-figure--flow {
    position: sticky;
    top: 130px;
  }

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

  .page-about .ab-local {
    margin-left: 25%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-flow__body,
  .page-about .ab-next__a {
    transition: none;
  }

  .page-about .ab-flow__node:hover .ab-flow__body,
  .page-about .ab-flow__node:focus-within .ab-flow__body {
    transform: none;
  }
}

.page-about {
  --line-soft: transparent;
}