.page-about {
  --about-block-gap: clamp(56px, 9vw, 120px);
  --about-accent-line: rgba(181, 116, 74, .32);
  display: block;
}

/* ---------- 刊头 ---------- */
.page-about .page-masthead {
  position: relative;
  padding: calc(var(--header-h) + clamp(48px, 8vw, 96px)) 0 clamp(56px, 8vw, 104px);
  background: linear-gradient(160deg, var(--navy-deep) 0%, var(--navy) 62%, #123058 100%);
  color: var(--ice-soft);
  overflow: hidden;
}

.page-about .breadcrumb__link,
.page-about .breadcrumb__current {
  color: rgba(214, 235, 247, .78);
}

.page-about .kicker {
  color: var(--ice);
  margin-top: 22px;
}

.page-about .page-masthead__title {
  font-family: var(--font-display);
  font-size: clamp(30px, 5.2vw, 62px);
  line-height: 1.08;
  letter-spacing: -.01em;
  color: #fff;
  margin: 14px 0 0;
  max-width: 20ch;
  font-weight: 600;
}

.page-about .page-masthead__desc {
  font-family: var(--font-body);
  font-size: clamp(15px, 1.4vw, 17.5px);
  line-height: 1.85;
  color: rgba(214, 235, 247, .88);
  max-width: 62ch;
  margin: 20px 0 0;
}

.page-about .about-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(32px, 5vw, 56px);
  background: var(--line-dark);
  border: 1px solid var(--line-dark);
}

.page-about .about-hero-stat {
  background: rgba(7, 18, 41, .62);
  padding: 20px 18px 22px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .about-hero-stat__num {
  font-size: clamp(28px, 3.4vw, 40px);
  line-height: 1;
  color: var(--ice);
}

.page-about .about-hero-stat__label {
  font-family: var(--font-body);
  font-size: 13.5px;
  letter-spacing: .04em;
  color: rgba(214, 235, 247, .72);
}

.page-about .page-masthead .edge-slant {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 46px;
  background: var(--cream);
  clip-path: polygon(0 100%, 100% 22%, 100% 100%);
}

/* ---------- 时间轴骨架 ---------- */
.page-about .about-spine {
  background: var(--cream);
}

.page-about .about-spine__inner {
  display: block;
}

.page-about .about-rail {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 18px 0;
  margin-bottom: clamp(36px, 6vw, 64px);
}

.page-about .about-rail__title {
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--stone);
  margin: 0 0 12px;
  text-transform: uppercase;
}

.page-about .about-rail__list {
  display: flex;
  gap: 8px 22px;
  list-style: none;
  margin: 0;
  padding: 0;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  white-space: nowrap;
  font-family: var(--font-body);
  font-size: 14px;
  color: var(--navy);
  text-decoration: none;
  padding-bottom: 3px;
  border-bottom: 1px solid transparent;
  transition: border-color .25s var(--ease), color .25s var(--ease);
}

.page-about .about-rail__link .mono {
  font-size: 12px;
  color: var(--clay);
  letter-spacing: .06em;
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--referee);
  border-bottom-color: var(--referee);
}

/* ---------- 通用区块 ---------- */
.page-about .about-block {
  padding: 0 0 var(--about-block-gap);
}

.page-about .about-block.section {
  padding-left: 0;
  padding-right: 0;
  padding-top: 0;
}

.page-about .about-block .section__head {
  max-width: 68ch;
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .about-block .section__index {
  color: var(--clay);
  font-size: 13px;
  letter-spacing: .18em;
}

.page-about .about-subhead {
  font-family: var(--font-display);
  font-size: 20px;
  letter-spacing: .02em;
  color: var(--navy);
  margin: 0 0 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.page-about .about-block p {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.78;
  color: var(--charcoal);
}

/* ---------- 01 起点 ---------- */
.page-about .about-origin {
  align-items: start;
  row-gap: 26px;
}

.page-about .about-origin__text p + p {
  margin-top: 16px;
}

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

/* ---------- 02 阶段 ---------- */
.page-about .about-block--phases {
  background: var(--ice-soft);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding-top: clamp(40px, 6vw, 72px);
  margin-bottom: var(--about-block-gap);
}

.page-about .about-block--phases .section__head,
.page-about .about-block--phases .about-phase,
.page-about .about-block--phases .about-phase__total {
  max-width: 1180px;
}

.page-about .about-phase {
  position: relative;
  display: block;
  border: 1px solid var(--line);
  background: var(--cream);
  margin-bottom: 18px;
  overflow: hidden;
  transition: transform .3s var(--ease), box-shadow .3s var(--ease);
}

.page-about .about-phase::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 6px;
  background: var(--clay);
}

.page-about .about-phase:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 26px rgba(11, 27, 58, .1);
}

.page-about .about-phase__mark {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 14px;
  padding: 16px 20px 14px 24px;
  border-bottom: 1px dashed var(--line-strong);
}

.page-about .about-phase__years {
  font-size: 15px;
  letter-spacing: .08em;
  color: var(--navy);
}

.page-about .about-phase__count {
  font-size: 20px;
  color: var(--referee);
  letter-spacing: .02em;
}

.page-about .about-phase__body {
  padding: 18px 20px 22px 24px;
}

.page-about .about-phase__title {
  font-family: var(--font-display);
  font-size: clamp(19px, 2vw, 24px);
  line-height: 1.3;
  color: var(--navy);
  margin: 0 0 10px;
}

.page-about .about-phase__body p {
  max-width: 74ch;
  margin: 0;
}

.page-about .about-phase--one::before { background: var(--clay); }
.page-about .about-phase--two::before { background: var(--turf); }
.page-about .about-phase--three::before { background: var(--ice); }

.page-about .about-phase__total {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.8;
  color: var(--navy);
  margin: 24px 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--line-strong);
}

.page-about .about-phase__total .mono {
  color: var(--referee);
  font-size: 17px;
}

/* ---------- 03 级别体系 ---------- */
.page-about .about-levels {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-level {
  background: var(--cream);
  padding: 22px 20px 26px;
  position: relative;
  transition: background-color .3s var(--ease);
}

.page-about .about-level__code {
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--stone);
  margin: 0 0 10px;
}

.page-about .about-level__name {
  font-family: var(--font-display);
  font-size: clamp(20px, 2.2vw, 26px);
  color: var(--navy);
  margin: 0 0 10px;
  line-height: 1.25;
}

.page-about .about-level p:last-child {
  margin: 0;
  font-size: 15.5px;
}

.page-about .about-level--intl { border-top: 4px solid var(--navy); }
.page-about .about-level--region { border-top: 4px solid var(--ice); }
.page-about .about-level--city { border-top: 4px solid var(--turf); }
.page-about .about-level--youth { border-top: 4px solid var(--clay); }

.page-about .about-level:hover {
  background: #fff;
}

/* ---------- 04 校订流程 ---------- */
.page-about .about-block--workflow {
  background: linear-gradient(180deg, var(--cream) 0%, var(--ice-soft) 100%);
  border-top: 1px solid var(--line);
  padding-top: clamp(40px, 6vw, 72px);
  margin-bottom: var(--about-block-gap);
}

.page-about .about-workflow {
  row-gap: 32px;
}

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

.page-about .about-team {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 4px;
  border-bottom: 1px solid var(--line);
}

.page-about .about-team__name {
  font-family: var(--font-display);
  font-size: 17px;
  letter-spacing: .02em;
  color: var(--navy);
}

.page-about .about-team__name::before {
  content: "";
  display: inline-block;
  width: 8px;
  height: 8px;
  margin-right: 9px;
  background: var(--turf);
  vertical-align: 1px;
}

.page-about .about-team__job {
  font-family: var(--font-body);
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--stone);
}

.page-about .about-step {
  border: 1px solid var(--line);
  background: var(--cream);
  margin-bottom: 10px;
}

.page-about .about-step .panel__summary {
  cursor: pointer;
  padding: 15px 18px;
  font-family: var(--font-body);
  font-size: 15.5px;
  font-weight: 600;
  color: var(--navy);
  list-style: none;
  position: relative;
  padding-right: 42px;
}

.page-about .about-step .panel__summary::-webkit-details-marker { display: none; }

.page-about .about-step .panel__summary::after {
  content: "+";
  position: absolute;
  right: 18px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--clay);
}

.page-about .about-step[open] .panel__summary::after { content: "–"; }

.page-about .about-step .panel__body {
  padding: 0 18px 16px;
  border-top: 1px solid var(--line);
}

.page-about .about-step .panel__body p {
  margin: 14px 0 0;
  font-size: 15px;
  color: var(--charcoal);
}

/* ---------- 05 数字档案库 ---------- */
.page-about .about-block--archive {
  background: var(--navy-deep);
  color: var(--ice-soft);
  padding-top: clamp(44px, 6vw, 80px);
  padding-bottom: clamp(48px, 7vw, 88px);
  margin-bottom: var(--about-block-gap);
}

.page-about .about-block--archive .section__index { color: var(--ice); }
.page-about .about-block--archive .section__title { color: #fff; }
.page-about .about-block--archive .section__desc { color: rgba(214, 235, 247, .82); }

.page-about .about-ruler {
  width: 100%;
  height: auto;
  display: block;
  max-height: 120px;
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .about-ruler__dots circle {
  fill: var(--navy-deep);
  stroke: var(--ice);
  stroke-width: 2;
}

.page-about .about-archive {
  row-gap: 32px;
  align-items: start;
}

.page-about .about-node {
  position: relative;
  padding: 18px 0 20px 22px;
  border-left: 1px solid var(--line-dark);
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: -4.5px;
  top: 24px;
  width: 8px;
  height: 8px;
  background: var(--ice);
  border-radius: 0;
}

.page-about .about-node__year {
  font-size: 15px;
  letter-spacing: .12em;
  color: var(--ice);
  margin: 0 0 6px;
}

.page-about .about-node__title {
  font-family: var(--font-display);
  font-size: clamp(19px, 2.2vw, 24px);
  color: #fff;
  margin: 0 0 8px;
  line-height: 1.3;
}

.page-about .about-node p {
  color: rgba(214, 235, 247, .84);
  margin: 0;
  font-size: 15.5px;
}

.page-about .about-archive__cta {
  margin: 24px 0 0;
  font-size: 15.5px;
  color: rgba(214, 235, 247, .9);
}

.page-about .about-archive__cta .link {
  color: var(--ice);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-archive__cta .link:hover { color: #fff; }

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

.page-about .about-archive__figure .media-frame__caption {
  background: rgba(7, 18, 41, .78);
  color: var(--ice-soft);
}

/* ---------- 06 合作 ---------- */
.page-about .about-partners {
  row-gap: 30px;
  align-items: start;
}

.page-about .about-partners__text p + p { margin-top: 15px; }

.page-about .about-partners__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px !important;
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 900px) {
  .page-about .about-spine__inner {
    display: grid;
    grid-template-columns: 200px minmax(0, 1fr);
    gap: clamp(28px, 4vw, 64px);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
    border-top: none;
    border-bottom: none;
    border-left: 1px solid var(--line);
    padding: 4px 0 4px 18px;
    margin-bottom: 0;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 12px;
    overflow: visible;
  }

  .page-about .about-phase {
    display: grid;
    grid-template-columns: 210px minmax(0, 1fr);
    align-items: stretch;
  }

  .page-about .about-phase__mark {
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    gap: 12px;
    border-bottom: none;
    border-right: 1px dashed var(--line-strong);
    padding: 26px 20px 26px 24px;
  }

  .page-about .about-phase__body {
    padding: 26px 26px 28px;
  }

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

@media (min-width: 1080px) {
  .page-about .about-spine__inner {
    grid-template-columns: 220px minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-phase,
  .page-about .about-rail__link,
  .page-about .about-level {
    transition: none;
  }

  .page-about .about-phase:hover {
    transform: none;
  }

  .page-about [data-reveal] {
    opacity: 1;
    transform: none;
  }
}