/* ============ 平台总览页 · page-about ============ */
.page-about {
  --about-index-w: 216px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(18px, 3.5vw, 36px) 0 clamp(28px, 5vw, 56px);
  border-bottom: 1px solid var(--hair);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -14% -18% auto -18%;
  height: 132%;
  pointer-events: none;
  background:
    radial-gradient(circle at 78% 20%, rgba(43, 232, 208, .16), transparent 44%),
    radial-gradient(circle at 6% 88%, rgba(255, 90, 43, .10), transparent 40%);
}

.page-about .about-hero__grid {
  position: relative;
  display: grid;
  gap: 26px;
}

.page-about .about-hero__lead h1 {
  margin: 12px 0 0;
  font-size: clamp(28px, 6.2vw, 50px);
  line-height: 1.14;
  letter-spacing: -.02em;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-hero__text {
  margin: 16px 0 0;
  max-width: 60ch;
  font-size: 15.5px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .about-hero__text--sub {
  font-size: 14px;
  color: var(--cyan-soft);
}

.page-about .about-hero__actions {
  margin-top: 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-hero__board {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-hero__board .stat {
  margin: 0;
  padding: 15px 14px;
  background: var(--panel);
}

.page-about .about-hero__board .stat__value {
  display: block;
  font-family: var(--mono);
  font-size: clamp(21px, 4.2vw, 30px);
  line-height: 1.05;
  font-variant-numeric: tabular-nums;
  color: var(--cyan);
}

.page-about .about-hero__board .stat--flame .stat__value {
  color: var(--flame);
}

.page-about .about-hero__board .stat__unit {
  margin-left: 3px;
  font-size: .44em;
  letter-spacing: .04em;
  color: var(--mist);
}

.page-about .about-hero__board .stat__label {
  display: block;
  margin-top: 7px;
  font-size: 12.5px;
  letter-spacing: .02em;
  color: var(--mist);
}

/* ---------- 章节索引 + 正文流 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  padding-top: clamp(26px, 4vw, 46px);
}

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

.page-about .about-toc .toc__list {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 14px;
  margin: 10px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-toc .toc__link {
  font-family: var(--mono);
  font-size: 12.5px;
  letter-spacing: .02em;
  text-decoration: none;
}

.page-about .about-sec,
.page-about .about-stage {
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .about-sec {
  padding-block: clamp(30px, 4.5vw, 52px);
  border-top: 1px solid var(--hair);
}

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

.page-about .about-copy > p {
  margin: 18px 0 0;
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.76;
  color: var(--mist);
}

.page-about .about-plates {
  margin-top: 26px;
}

/* ---------- 校验流程 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-step {
  position: relative;
  padding: 18px 16px 20px 64px;
  background: var(--ink-2);
}

.page-about .about-step__no {
  position: absolute;
  left: 16px;
  top: 18px;
  font-family: var(--mono);
  font-size: 15px;
  font-variant-numeric: tabular-nums;
  color: var(--flame);
}

.page-about .about-step__title {
  margin: 0;
  font-size: 16px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-step__desc {
  margin: 7px 0 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 图文容器 ---------- */
.page-about .about-figure {
  margin: 26px 0 0;
}

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

/* ---------- 展签式数据块 ---------- */
.page-about .about-facts {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: 26px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-fact {
  padding: 18px 16px;
  background: var(--ink-2);
  transition: background-color .25s ease;
}

.page-about .about-fact:hover,
.page-about .about-fact:focus-within {
  background: var(--panel);
}

.page-about .about-fact__label {
  margin: 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .about-fact__num {
  display: block;
  margin: 10px 0 0;
  font-family: var(--mono);
  font-size: clamp(25px, 5vw, 34px);
  line-height: 1.05;
  font-variant-numeric: tabular-nums;
  color: var(--paper);
}

.page-about .about-fact__num small {
  margin-left: 5px;
  font-size: .38em;
  font-weight: 400;
  letter-spacing: .04em;
  color: var(--mist);
}

.page-about .about-fact__more {
  margin: 12px 0 0;
  padding-top: 10px;
  border-top: 1px solid var(--hair);
  font-size: 13px;
  line-height: 1.65;
  color: var(--mist);
  transition: color .25s ease, border-color .25s ease;
}

.page-about .about-fact:hover .about-fact__more,
.page-about .about-fact:focus-within .about-fact__more {
  color: var(--cyan-soft);
  border-color: var(--line-strong);
}

/* ---------- 版本演进 ---------- */
.page-about .about-timeline {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  margin: 4px 0 20px;
  padding: 0;
  list-style: none;
}

.page-about .about-timeline__item a {
  display: block;
  padding: 12px 12px 14px;
  background: var(--panel);
  border-top: 3px solid var(--cyan);
  text-decoration: none;
  transition: background-color .22s ease, transform .22s ease;
}

.page-about .about-timeline__item:nth-child(2) a { border-top-color: var(--amber); }
.page-about .about-timeline__item:nth-child(3) a { border-top-color: var(--flame); }
.page-about .about-timeline__item:nth-child(4) a { border-top-color: var(--cyan-soft); }

.page-about .about-timeline__item a:hover,
.page-about .about-timeline__item a:focus-visible {
  background: var(--ink);
  transform: translateY(-2px);
}

.page-about .about-timeline__year {
  display: block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--mist);
}

.page-about .about-timeline__name {
  display: block;
  margin-top: 6px;
  font-size: 14px;
  color: var(--paper);
}

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

.page-about .about-stage {
  padding: 20px 18px 22px;
  background: var(--ink-2);
}

.page-about .about-stage__tag {
  margin: 0;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--flame);
}

.page-about .about-stage__title {
  margin: 8px 0 0;
  font-size: 17px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-stage__text {
  margin: 9px 0 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--mist);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  display: grid;
  gap: 26px;
}

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

.page-about .about-team__fig {
  margin: 0;
}

/* ---------- 配合与响应 ---------- */
.page-about .about-coop {
  margin-top: 24px;
}

.page-about .about-coop__card {
  padding: 18px 16px 20px;
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-left: 3px solid var(--amber);
}

.page-about .about-coop__card:nth-child(2) {
  border-left-color: var(--cyan);
}

.page-about .about-coop__card h3 {
  margin: 10px 0 0;
  font-size: 17px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-coop__card p:last-child {
  margin: 9px 0 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .about-coop__foot {
  margin: 22px 0 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--mist);
}

.page-about .about-coop__foot a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--line-strong);
}

.page-about .about-coop__foot a:hover,
.page-about .about-coop__foot a:focus-visible {
  color: var(--cyan-soft);
}

/* ---------- 收尾色带 ---------- */
.page-about .about-cta {
  margin-top: clamp(30px, 5vw, 54px);
  padding: clamp(22px, 4vw, 38px);
  border-radius: var(--radius);
}

.page-about .about-cta__inner {
  max-width: 700px;
}

.page-about .about-cta__title {
  margin: 12px 0 0;
  font-size: clamp(20px, 3.4vw, 27px);
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-about .about-cta__text {
  margin: 12px 0 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--cyan-soft);
}

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

/* ---------- 返回顶部 ---------- */
.page-about .totop {
  margin-top: clamp(24px, 4vw, 40px);
}

/* ---------- 桌面与平板 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__board .stat {
    padding: 18px 16px;
  }

  .page-about .about-facts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

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

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

  .page-about .about-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-step {
    padding: 22px 18px 24px;
  }

  .page-about .about-step__no {
    position: static;
    display: block;
    margin-bottom: 12px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    align-items: end;
    gap: 48px;
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: 34px;
    align-items: start;
  }
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: var(--about-index-w) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: calc(var(--header-h) + 24px);
  }

  .page-about .about-toc .toc__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 2px;
  }
}

/* ---------- 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-fact,
  .page-about .about-fact__more,
  .page-about .about-timeline__item a {
    transition: none;
  }

  .page-about .about-timeline__item a:hover,
  .page-about .about-timeline__item a:focus-visible {
    transform: none;
  }
}