.page-about {
  --about-measure: 62ch;
  --about-sec-gap: clamp(56px, 9vw, 128px);
  --about-tint: rgba(207, 227, 214, 0.45);
  padding-bottom: clamp(48px, 8vw, 104px);
}

.page-about :focus-visible {
  outline: 2px solid var(--yellow);
  outline-offset: 3px;
}

.page-about .crumbs {
  margin-top: 20px;
}

/* ---------- 首屏：主题声明 + 章节目录 ---------- */

.page-about .about-intro {
  margin-top: clamp(24px, 4vw, 48px);
}

.page-about .about-intro__kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--yellow-deep);
}

.page-about .about-title {
  margin: 0;
  max-width: 20ch;
  font-size: clamp(34px, 6.4vw, 72px);
  line-height: 1.02;
  letter-spacing: -0.02em;
  font-weight: 900;
  color: var(--ink);
}

.page-about .about-intro__lede {
  max-width: 56ch;
  margin: 22px 0 0;
  font-size: 17px;
  line-height: 1.75;
  color: var(--ink);
}

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

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 4px solid var(--indigo);
}

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

.page-about .about-toc__link {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 13px 2px;
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
  transition: color 140ms ease, padding-left 140ms ease;
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  color: var(--green);
  padding-left: 8px;
}

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

@media (min-width: 760px) {
  .page-about .about-toc__list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: clamp(24px, 4vw, 64px);
  }
}

/* ---------- 章节骨架 ---------- */

.page-about .about-sec {
  margin-top: var(--about-sec-gap);
  scroll-margin-top: 84px;
}

.page-about .about-rule {
  display: block;
  width: 100%;
  height: 5px;
  margin-bottom: clamp(20px, 3vw, 32px);
  background: var(--indigo);
}

.page-about .about-sec--region .about-rule {
  background: var(--wine);
}

.page-about .about-copy {
  max-width: var(--about-measure);
  font-size: 17px;
  line-height: 1.75;
  color: var(--ink);
}

.page-about .about-copy p {
  margin: 0 0 1.1em;
}

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

.page-about .about-copy--tight {
  margin-top: 20px;
  font-size: 15.5px;
}

.page-about .about-copy--links {
  margin-top: clamp(24px, 4vw, 36px);
}

/* ---------- 图片容器 ---------- */

.page-about .figure-frame {
  margin: 0;
}

.page-about .figure-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: var(--r-md);
  object-fit: cover;
}

.page-about .figure-frame__caption {
  margin-top: 10px;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .about-figure {
  margin: clamp(24px, 4vw, 40px) 0;
}

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

/* ---------- 来源分层 ---------- */

.page-about .about-sources {
  margin-top: clamp(24px, 4vw, 40px);
  align-items: start;
  row-gap: 28px;
}

.page-about .about-src {
  list-style: none;
  margin: 0 0 4px;
  padding: 0;
  border-top: 1px solid var(--line-strong);
}

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

.page-about .about-src__name {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .about-src__name::before {
  content: "";
  display: inline-block;
  width: 9px;
  height: 9px;
  margin-right: 10px;
  border-radius: 2px;
  background: var(--green);
  vertical-align: 2px;
}

.page-about .about-src__item:nth-child(2) .about-src__name::before { background: var(--yellow); }
.page-about .about-src__item:nth-child(3) .about-src__name::before { background: var(--indigo); }
.page-about .about-src__item:nth-child(4) .about-src__name::before { background: var(--mint); }

.page-about .about-src__desc {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--ink);
}

/* ---------- 术语与口径注释 ---------- */

.page-about .about-note {
  max-width: 76ch;
  margin-top: clamp(28px, 4vw, 44px);
  padding: 18px 20px;
  background: var(--mint);
  border-left: 5px solid var(--indigo);
  border-radius: var(--r-md);
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--ink);
}

.page-about .about-note p {
  margin: 0;
}

.page-about .about-term {
  position: relative;
  display: inline-block;
  font-weight: 700;
  cursor: help;
  border-bottom: 1px dashed var(--yellow-deep);
}

.page-about .about-term__tip {
  position: absolute;
  left: 0;
  bottom: calc(100% + 10px);
  z-index: 5;
  width: min(320px, 76vw);
  padding: 12px 14px;
  font-size: 13.5px;
  font-weight: 400;
  line-height: 1.65;
  color: var(--white);
  background: var(--ink);
  border: 1px solid var(--yellow-deep);
  border-radius: var(--r-sm);
  opacity: 0;
  visibility: hidden;
  transform: translateY(4px);
  transition: opacity 140ms ease, transform 140ms ease, visibility 140ms ease;
}

.page-about .about-term:hover .about-term__tip,
.page-about .about-term:focus .about-term__tip,
.page-about .about-term:focus-within .about-term__tip {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* ---------- 三步流程 ---------- */

.page-about .about-flow {
  list-style: none;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 0;
  border-top: 3px solid var(--green);
}

.page-about .about-flow__step {
  padding: 22px 18px 24px;
  border-bottom: 1px solid var(--line);
  border-left: 5px solid transparent;
  transition: background-color 160ms ease, border-color 160ms ease;
}

.page-about .about-flow__step:hover,
.page-about .about-flow__step:focus {
  background: var(--tint, rgba(207, 227, 214, 0.6));
  border-left-color: var(--yellow);
}

.page-about .about-flow__idx {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--yellow-deep);
}

.page-about .about-flow__title {
  margin: 8px 0 8px;
  font-size: 20px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .about-flow__body {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--ink);
}

.page-about .about-flow__extra {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.65;
  color: var(--muted);
  transition: color 160ms ease;
}

.page-about .about-flow__step:hover .about-flow__extra,
.page-about .about-flow__step:focus .about-flow__extra {
  color: var(--green-deep);
}

@media (min-width: 800px) {
  .page-about .about-flow {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    border-top: 0;
  }

  .page-about .about-flow__step {
    padding: 20px 22px 26px;
    border-bottom: 0;
    border-right: 1px solid var(--line);
    border-left: 0;
    border-top: 5px solid transparent;
  }

  .page-about .about-flow__step:last-child {
    border-right: 0;
  }

  .page-about .about-flow__step:hover,
  .page-about .about-flow__step:focus {
    border-left-color: transparent;
    border-top-color: var(--yellow);
  }
}

/* ---------- 节奏表 ---------- */

.page-about .about-table-wrap {
  margin-top: clamp(28px, 4vw, 48px);
}

.page-about .about-table__title {
  margin: 0 0 10px;
  font-size: 13px;
  letter-spacing: 0.06em;
  font-weight: 700;
  color: var(--muted);
}

/* ---------- 团队 ---------- */

.page-about .about-team {
  display: grid;
  gap: 28px;
  margin-top: clamp(24px, 4vw, 40px);
}

.page-about .about-team__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(56px, 9vw, 96px);
  font-weight: 700;
  line-height: 0.9;
  color: var(--green);
  letter-spacing: -0.03em;
}

.page-about .about-team__unit {
  margin-left: 6px;
  font-size: 0.36em;
  color: var(--ink);
}

.page-about .about-team__cap {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .about-team__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 2px solid var(--indigo);
}

.page-about .about-team__item {
  display: flex;
  gap: 18px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-team__count {
  flex: none;
  min-width: 46px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 28px;
  line-height: 1;
  color: var(--yellow-deep);
}

.page-about .about-team__desc h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .about-team__desc p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--ink);
}

@media (min-width: 860px) {
  .page-about .about-team {
    grid-template-columns: minmax(200px, 260px) minmax(0, 1fr);
    gap: clamp(32px, 5vw, 72px);
  }
}

/* ---------- 改版时间线 ---------- */

.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 0 0 0 26px;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 8px;
  width: 5px;
  background: var(--indigo);
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: clamp(28px, 4vw, 44px);
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 5px;
  width: 17px;
  height: 17px;
  box-sizing: border-box;
  border: 5px solid var(--green);
  border-radius: 50%;
  background: var(--white);
}

.page-about .about-timeline__item:nth-child(2)::before { border-color: var(--yellow-deep); }
.page-about .about-timeline__item:nth-child(3)::before { border-color: var(--indigo); }

.page-about .about-timeline__year {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--green-deep);
}

.page-about .about-timeline__title {
  margin: 0 0 6px;
  font-size: 20px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .about-timeline__sum {
  max-width: 60ch;
  margin: 0 0 12px;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .about-timeline__more {
  max-width: 60ch;
  padding: 0 16px;
  background: var(--about-tint);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-md);
}

.page-about .about-timeline__more summary {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 0;
  font-size: 14px;
  font-weight: 700;
  color: var(--green-deep);
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-timeline__more summary::after {
  content: "展开";
  margin-left: auto;
  padding: 1px 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--yellow-deep);
  border: 1px solid var(--yellow-deep);
  border-radius: 999px;
}

.page-about .about-timeline__more[open] summary::after {
  content: "收起";
}

.page-about .about-timeline__more p {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink);
}

/* ---------- 服务地区与备案 ---------- */

.page-about .about-region-figure {
  margin: 0 0 clamp(24px, 4vw, 40px);
}

.page-about .about-record {
  max-width: 76ch;
  margin-top: clamp(24px, 4vw, 40px);
  padding: 18px 20px;
  background: rgba(123, 34, 51, 0.06);
  border: 2px solid var(--wine);
  border-left-width: 8px;
  border-radius: var(--r-md);
}

.page-about .about-record__icp {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--wine);
}

.page-about .about-record__text {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--ink);
}

/* ---------- 小屏与减动效 ---------- */

@media (max-width: 560px) {
  .page-about .about-term {
    display: block;
    border-bottom: 0;
  }

  .page-about .about-term__tip {
    position: static;
    display: block;
    width: auto;
    margin-top: 8px;
    opacity: 1;
    visibility: visible;
    transform: none;
  }

  .page-about .about-team__item {
    gap: 14px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc__link,
  .page-about .about-flow__step,
  .page-about .about-flow__extra,
  .page-about .about-term__tip {
    transition: none;
  }
}

.page-about {
  --tint: transparent;
}