.page-about {
  --about-rail: 190px;
  background: var(--ink);
  color: var(--paper);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-top: clamp(20px, 3.5vw, 44px);
  padding-bottom: clamp(40px, 6vw, 88px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: 36px;
}

.page-about .about-hero__title {
  margin: 14px 0 20px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(32px, 5.2vw, 64px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--paper);
  max-width: 18ch;
}

.page-about .about-hero__text {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 0;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-facts__item {
  padding: 14px 0 16px;
  border-bottom: 1px solid var(--line);
  min-width: 0;
}

.page-about .about-facts__item:nth-child(even) {
  padding-left: 16px;
  border-left: 1px solid var(--line);
}

.page-about .about-facts__item:nth-child(odd) {
  padding-right: 16px;
}

.page-about .about-facts__label {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-facts__num {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(28px, 3.4vw, 42px);
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--paper);
}

.page-about .about-facts__num span {
  margin-left: 4px;
  font-size: 0.38em;
  letter-spacing: 0;
  color: var(--muted);
}

/* ---------- 通用小节头 ---------- */
.page-about .about-head {
  max-width: 66ch;
  margin-bottom: clamp(28px, 4vw, 48px);
}

.page-about .about-head__title {
  margin: 12px 0 14px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(26px, 3.4vw, 44px);
  line-height: 1.12;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-head__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 版本演进 ---------- */
.page-about .about-timeline {
  border-top: 1px solid var(--line);
}

.page-about .about-timeline__figure {
  margin: 0 0 clamp(32px, 5vw, 64px);
}

.page-about .about-timeline__grid {
  display: grid;
  gap: 28px;
}

.page-about .about-timeline__indexTitle {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-timeline__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-timeline__link {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 11px 0;
  border-bottom: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.5;
  color: var(--muted);
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-timeline__code {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--cyan);
  flex: none;
}

.page-about .about-timeline__link:hover {
  color: var(--paper);
  border-bottom-color: var(--cyan);
}

.page-about .about-timeline__link:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .about-timeline__entries {
  min-width: 0;
}

.page-about .about-node {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 10px 16px;
  padding: 26px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-node:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .about-node__num {
  grid-row: 1 / span 2;
  margin: 0;
  padding-top: 5px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about .about-node__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(19px, 2.1vw, 26px);
  line-height: 1.25;
  color: var(--paper);
  transition: color var(--dur) var(--ease);
}

.page-about .about-node__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

@media (hover: hover) {
  .page-about .about-node:hover .about-node__title {
    color: var(--cyan);
  }
}

/* ---------- 团队分工 ---------- */
.page-about .about-team {
  border-top: 1px solid var(--line);
}

.page-about .about-team__grid {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-role {
  padding: 26px 0;
  border-bottom: 1px solid var(--line);
  min-width: 0;
}

.page-about .about-role__idx {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--orange);
}

.page-about .about-role__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(19px, 2vw, 25px);
  line-height: 1.25;
  color: var(--paper);
}

.page-about .about-role__text {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
  max-width: 46ch;
}

.page-about .about-role__meta {
  margin: 0;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--green);
}

/* ---------- 数据流程（宽画布） ---------- */
.page-about .about-flow {
  border-top: 1px solid var(--line);
}

.page-about .about-flow__figure {
  margin: 0 0 clamp(32px, 5vw, 56px);
}

.page-about .about-pipeline {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-pipeline__step {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-width: 0;
  padding: 28px 20px 24px;
  background: var(--ink);
  transition: background var(--dur) var(--ease);
}

.page-about .about-pipeline__step::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--step-accent, var(--cyan));
}

.page-about .about-pipeline__step:nth-child(1) { --step-accent: var(--cyan); }
.page-about .about-pipeline__step:nth-child(2) { --step-accent: var(--green); }
.page-about .about-pipeline__step:nth-child(3) { --step-accent: var(--orange); }
.page-about .about-pipeline__step:nth-child(4) { --step-accent: var(--cyan-press); }

.page-about .about-pipeline__idx {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-pipeline__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 19px;
  line-height: 1.28;
  color: var(--paper);
}

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

.page-about .about-pipeline__note {
  margin: auto 0 0;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.65;
  letter-spacing: 0.02em;
  color: var(--cyan);
  transition: color var(--dur) var(--ease);
}

@media (hover: hover) {
  .page-about .about-pipeline__step:hover {
    background: var(--cyan-soft);
  }
  .page-about .about-pipeline__step:hover .about-pipeline__note {
    color: var(--paper);
  }
}

.page-about .about-pipeline__step:focus-within {
  background: var(--cyan-soft);
}

/* ---------- 覆盖与规模（暖纸面板） ---------- */
.page-about .section--paper {
  color: var(--ink);
}

.page-about .section--paper .eyebrow {
  color: var(--grid-color);
}

.page-about .about-scale__grid {
  display: grid;
  gap: 32px;
}

.page-about .about-scale__title {
  margin: 12px 0 14px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(26px, 3.4vw, 44px);
  line-height: 1.12;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-scale__text {
  margin: 0 0 24px;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--grid-color);
}

.page-about .about-scale__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--paper-shadow);
}

.page-about .about-scale__list li {
  padding: 14px 0;
  border-bottom: 1px solid var(--paper-shadow);
  font-size: 14px;
  line-height: 1.7;
  color: var(--grid-color);
}

.page-about .about-scale__list strong {
  display: inline-block;
  margin-right: 6px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 20px;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--ink);
}

.page-about .about-scale__figure {
  margin: 0;
  align-self: start;
}

/* ---------- 协作与登记 ---------- */
.page-about .about-partners {
  border-top: 1px solid var(--line);
}

.page-about .about-partners__grid {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-partners__col {
  padding: 26px 0 30px;
  border-bottom: 1px solid var(--line);
  min-width: 0;
}

.page-about .about-partners__title {
  margin: 12px 0 12px;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(20px, 2.3vw, 28px);
  line-height: 1.25;
  color: var(--paper);
}

.page-about .about-partners__text {
  margin: 0;
  max-width: 52ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 接下来 ---------- */
.page-about .about-next {
  border-top: 1px solid var(--line);
  padding-bottom: clamp(56px, 8vw, 112px);
}

.page-about .about-next__grid {
  display: grid;
  gap: 30px;
  align-items: end;
}

.page-about .about-next__title {
  margin: 12px 0 14px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(26px, 3.4vw, 42px);
  line-height: 1.12;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-next__text {
  margin: 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .about-pipeline {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-role {
    display: grid;
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 8px 40px;
    align-items: start;
  }

  .page-about .about-role__idx {
    grid-column: 1;
    grid-row: 1;
  }

  .page-about .about-role__title {
    grid-column: 1;
    grid-row: 2;
    margin-bottom: 0;
  }

  .page-about .about-role__text {
    grid-column: 2;
    grid-row: 1 / span 2;
    margin: 0;
    max-width: none;
  }

  .page-about .about-role__meta {
    grid-column: 1 / -1;
    grid-row: 3;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: clamp(32px, 5vw, 72px);
    align-items: end;
  }

  .page-about .about-timeline__grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(32px, 5vw, 72px);
  }

  .page-about .about-timeline__index {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
  }

  .page-about .about-scale__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 380px);
    gap: clamp(32px, 5vw, 72px);
    align-items: start;
  }

  .page-about .about-partners__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 clamp(32px, 5vw, 72px);
  }

  .page-about .about-next__grid {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: clamp(32px, 5vw, 72px);
  }
}

@media (min-width: 1080px) {
  .page-about .about-pipeline {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-node {
    grid-template-columns: 60px minmax(0, 1fr) minmax(0, 1fr);
    gap: 0 40px;
    align-items: start;
  }

  .page-about .about-node__num {
    grid-column: 1;
    grid-row: 1;
    padding-top: 6px;
  }

  .page-about .about-node__title {
    grid-column: 2;
    grid-row: 1;
  }

  .page-about .about-node__text {
    grid-column: 3;
    grid-row: 1;
    max-width: 46ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-timeline__link,
  .page-about .about-node__title,
  .page-about .about-pipeline__step,
  .page-about .about-pipeline__note {
    transition: none;
  }
}