.page-about {
  --about-line: rgba(10, 26, 42, 0.12);
  --about-line-light: rgba(246, 244, 239, 0.18);
  --about-gap: clamp(28px, 5vw, 64px);
}

/* ---------- 章节通用 ---------- */
.page-about .chapter {
  position: relative;
  padding-block: clamp(56px, 8vw, 104px);
}

.page-about .chapter__grid {
  display: grid;
  gap: var(--about-gap);
}

.page-about .chapter__head {
  display: grid;
  gap: 14px;
  align-content: start;
}

.page-about .chapter__num {
  display: inline-block;
  font-size: 13px;
  letter-spacing: 0.22em;
  color: var(--copper);
  padding-bottom: 6px;
  border-bottom: 1px solid var(--copper);
  width: fit-content;
}

.page-about .chapter__head .title-1,
.page-about .chapter__head h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(30px, 6vw, 52px);
  line-height: 1.15;
  letter-spacing: -0.01em;
}

.page-about .chapter__head .lede {
  margin: 0;
  max-width: 46ch;
  color: var(--muted-light);
}

.page-about .chapter__head--light .title-1,
.page-about .chapter__head--light h2 {
  color: var(--paper);
}

.page-about .chapter__head--light .lede {
  color: var(--muted-dark);
}

.page-about .chapter__body .prose + .prose {
  margin-top: 18px;
}

.page-about .chapter__media {
  margin-top: var(--about-gap);
}

.page-about .principle-list {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  gap: 20px;
}

.page-about .principle-item {
  display: grid;
  grid-template-columns: 14px 1fr;
  gap: 16px;
  padding-top: 18px;
  border-top: 1px solid var(--about-line);
}

.page-about .principle-item__mark {
  width: 10px;
  height: 10px;
  margin-top: 8px;
  border-radius: 50%;
  background: var(--celadon);
  box-shadow: 0 0 0 4px rgba(111, 155, 141, 0.18);
}

.page-about .principle-item__title {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 600;
  color: var(--ink);
}

.page-about .principle-item__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted-light);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-top: clamp(40px, 6vw, 72px);
  padding-bottom: clamp(48px, 7vw, 88px);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: auto -120px -140px auto;
  width: 380px;
  height: 380px;
  border-radius: 50%;
  background: radial-gradient(circle at center, rgba(192, 138, 62, 0.22), transparent 68%);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .breadcrumbs {
  margin-bottom: 26px;
}

.page-about .about-hero__eyebrow {
  margin: 0 0 18px;
}

.page-about .about-hero__title {
  margin: 0;
  max-width: 22ch;
  font-family: var(--font-display);
  font-weight: 200;
  font-size: clamp(38px, 8vw, 76px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero__lede {
  margin: 24px 0 0;
  max-width: 44ch;
  font-size: clamp(15px, 2.4vw, 17px);
  line-height: 1.85;
  color: var(--muted-dark);
}

.page-about .about-hero__facts {
  margin: clamp(34px, 6vw, 56px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px 26px;
  border-top: 1px solid var(--about-line-light);
  padding-top: 26px;
}

.page-about .about-fact {
  display: grid;
  gap: 8px;
}

.page-about .about-fact__key {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--silver);
}

.page-about .about-fact__val {
  margin: 0;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 500;
  color: var(--paper);
}

.page-about .about-fact__num {
  font-family: var(--font-mono);
  font-size: 30px;
  color: var(--copper-soft);
  margin-right: 4px;
}

/* ---------- 章节导航条 ---------- */
.page-about .about-anchor-nav {
  padding-block: 18px;
  border-bottom: 1px solid var(--about-line);
  position: sticky;
  top: 0;
  z-index: 5;
}

.page-about .chapter-rail {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  scrollbar-width: none;
  padding-bottom: 4px;
}

.page-about .chapter-rail::-webkit-scrollbar {
  display: none;
}

.page-about .chapter-link {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--about-line);
  background: transparent;
  color: var(--ink);
  font-size: 14px;
  text-decoration: none;
  transition: border-color 0.25s var(--ease), color 0.25s var(--ease), background-color 0.25s var(--ease);
}

.page-about .chapter-link__num {
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--copper);
}

.page-about .chapter-link:hover,
.page-about .chapter-link:focus-visible {
  border-color: var(--copper);
  background: rgba(192, 138, 62, 0.1);
  outline: none;
}

/* ---------- 三大支柱 ---------- */
.page-about .pillar-grid {
  display: grid;
  gap: 22px;
  margin-top: var(--about-gap);
}

.page-about .pillar {
  display: grid;
  gap: 12px;
  padding: clamp(22px, 4vw, 32px);
  border-radius: var(--radius-lg);
  background: rgba(246, 244, 239, 0.04);
  border: 1px solid var(--about-line-light);
  transition: border-color 0.3s var(--ease), transform 0.3s var(--ease);
}

.page-about .pillar:hover {
  border-color: var(--copper);
  transform: translateY(-4px);
}

.page-about .pillar__index {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--copper-soft);
}

.page-about .pillar__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(22px, 3.4vw, 28px);
  font-weight: 500;
  color: var(--paper);
}

.page-about .pillar__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted-dark);
}

.page-about .pillar__list {
  margin: 6px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
  border-top: 1px solid var(--about-line-light);
  padding-top: 16px;
}

.page-about .pillar__list li {
  position: relative;
  padding-left: 18px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted-dark);
}

.page-about .pillar__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--celadon);
}

.page-about .pillars__cta {
  margin: clamp(30px, 5vw, 46px) 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  list-style: none;
  margin: var(--about-gap) 0 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .timeline__item {
  position: relative;
  display: grid;
  grid-template-columns: 26px 1fr;
  gap: 18px;
  padding-bottom: 24px;
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: 12px;
  top: 22px;
  bottom: 0;
  width: 1px;
  background: linear-gradient(to bottom, var(--copper), rgba(192, 138, 62, 0.12));
}

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

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

.page-about .timeline__node {
  position: relative;
  z-index: 1;
  width: 14px;
  height: 14px;
  margin-top: 8px;
  margin-left: 5px;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--copper);
  transition: background-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.page-about .timeline__item:hover .timeline__node {
  background: var(--copper);
  box-shadow: 0 0 0 6px rgba(192, 138, 62, 0.16);
}

.page-about .timeline__card {
  padding: 20px 22px;
  border-radius: var(--radius-md);
  background: var(--silver-soft);
  border-left: 2px solid transparent;
  transition: border-color 0.28s var(--ease), background-color 0.28s var(--ease);
}

.page-about .timeline__item:hover .timeline__card {
  border-left-color: var(--copper);
  background: #f0ede6;
}

.page-about .timeline__meta {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--copper-deep);
}

.page-about .timeline__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 600;
  color: var(--ink);
}

.page-about .timeline__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted-light);
}

/* ---------- 服务区域 ---------- */
.page-about .network {
  display: grid;
  gap: var(--about-gap);
  margin-top: var(--about-gap);
}

.page-about .network__map {
  display: grid;
  gap: 16px;
}

.page-about .network__svg {
  width: 100%;
  height: auto;
  background: var(--paper);
  border-radius: var(--radius-lg);
  padding: 10px;
}

.page-about .network__svg line {
  stroke: var(--copper);
  stroke-width: 1;
  stroke-dasharray: 5 6;
  opacity: 0.55;
}

.page-about .network__svg .node {
  fill: var(--celadon);
  transition: r 0.25s var(--ease);
}

.page-about .network__svg .node--main {
  fill: var(--ink);
  stroke: var(--copper);
  stroke-width: 3;
}

.page-about .network__label {
  font-family: var(--font-mono);
  font-size: 11px;
  fill: var(--muted-light);
  letter-spacing: 0.06em;
}

.page-about .region-filter {
  margin-top: 26px;
  padding-top: 22px;
  border-top: 1px solid var(--about-line);
}

.page-about .region-filter__title {
  margin: 0 0 12px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--muted-light);
}

.page-about .region-filter__tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 18px;
}

.page-about .region-tab {
  padding: 8px 18px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--about-line);
  background: transparent;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--ink);
  cursor: pointer;
  transition: border-color 0.25s var(--ease), background-color 0.25s var(--ease), color 0.25s var(--ease);
}

.page-about .region-tab:hover {
  border-color: var(--copper);
}

.page-about .region-tab.is-active {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
}

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

.page-about .region-item {
  display: grid;
  gap: 6px;
  padding: 16px 18px;
  border-radius: var(--radius-md);
  background: var(--paper);
  border: 1px solid var(--about-line);
}

.page-about .region-item.is-hidden {
  display: none;
}

.page-about .region-item__name {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 600;
  color: var(--ink);
}

.page-about .region-item__desc {
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted-light);
}

/* ---------- 团队 ---------- */
.page-about .team {
  display: grid;
  gap: var(--about-gap);
  margin-top: var(--about-gap);
}

.page-about .team__grid {
  display: grid;
  gap: 16px;
}

.page-about .team-cell {
  padding: 22px;
  border-radius: var(--radius-md);
  background: var(--silver-soft);
  display: grid;
  gap: 8px;
  align-content: start;
  transition: transform 0.28s var(--ease), box-shadow 0.28s var(--ease);
}

.page-about .team-cell:hover {
  transform: translateY(-3px);
  box-shadow: 0 14px 30px rgba(10, 26, 42, 0.08);
}

.page-about .team-cell--celadon {
  background: rgba(111, 155, 141, 0.14);
  border: 1px solid rgba(111, 155, 141, 0.4);
}

.page-about .team-cell__tag {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--copper-deep);
}

.page-about .team-cell__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 600;
  color: var(--ink);
}

.page-about .team-cell__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted-light);
}

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

/* ---------- 资质 ---------- */
.page-about .credit {
  display: grid;
  gap: var(--about-gap);
  margin-top: var(--about-gap);
}

.page-about .credit__main .prose + .prose {
  margin-top: 16px;
}

.page-about .credit__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--about-line-light);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.page-about .credit-item {
  display: grid;
  grid-template-columns: 78px 1fr;
  gap: 16px;
  padding: 18px;
  background: var(--ink-2);
}

.page-about .credit-item__key {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--copper-soft);
}

.page-about .credit-item__val {
  font-size: 14px;
  line-height: 1.75;
  color: var(--paper);
}

/* ---------- 版本面板 ---------- */
.page-about .panel-switch {
  margin-top: var(--about-gap);
}

.page-about .panel-switch__tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 20px;
}

.page-about .panel-tab {
  padding: 9px 18px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--about-line);
  background: transparent;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--ink);
  cursor: pointer;
  transition: border-color 0.25s var(--ease), background-color 0.25s var(--ease), color 0.25s var(--ease);
}

.page-about .panel-tab:hover {
  border-color: var(--copper);
}

.page-about .panel-tab.is-active {
  background: var(--copper);
  border-color: var(--copper);
  color: var(--ink);
}

.page-about .panel-frame {
  padding: clamp(22px, 4vw, 34px);
  border-radius: var(--radius-lg);
  background: var(--ink);
  min-height: 190px;
}

.page-about .panel-view {
  display: none;
}

.page-about .panel-view.is-active {
  display: block;
}

.page-about .panel-view__meta {
  margin: 0 0 12px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--copper-soft);
}

.page-about .panel-view__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: clamp(20px, 3.2vw, 26px);
  font-weight: 500;
  color: var(--paper);
}

.page-about .panel-view__text {
  margin: 0;
  max-width: 52ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted-dark);
}

.page-about .panel-notes {
  margin-top: 26px;
  display: grid;
  gap: 18px;
}

.page-about .panel-note {
  padding-top: 18px;
  border-top: 1px solid var(--about-line);
}

.page-about .panel-note__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 600;
  color: var(--ink);
}

.page-about .panel-note__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted-light);
}

/* ---------- 问答 ---------- */
.page-about .qa {
  margin-top: var(--about-gap);
  display: grid;
  gap: 0;
}

.page-about .qa-item {
  border-top: 1px solid var(--about-line);
  padding: 4px 0;
}

.page-about .qa-item:last-of-type {
  border-bottom: 1px solid var(--about-line);
}

.page-about .qa-item__q {
  cursor: pointer;
  list-style: none;
  padding: 20px 34px 20px 0;
  position: relative;
  font-family: var(--font-display);
  font-size: clamp(16px, 2.6vw, 19px);
  font-weight: 500;
  line-height: 1.5;
  color: var(--ink);
  transition: color 0.25s var(--ease);
}

.page-about .qa-item__q::-webkit-details-marker {
  display: none;
}

.page-about .qa-item__q::after {
  content: "";
  position: absolute;
  right: 6px;
  top: 50%;
  width: 11px;
  height: 11px;
  border-right: 1.5px solid var(--copper);
  border-bottom: 1.5px solid var(--copper);
  transform: translateY(-70%) rotate(45deg);
  transition: transform 0.3s var(--ease);
}

.page-about .qa-item[open] .qa-item__q {
  color: var(--copper-deep);
}

.page-about .qa-item[open] .qa-item__q::after {
  transform: translateY(-30%) rotate(-135deg);
}

.page-about .qa-item__a {
  padding: 0 0 22px;
  max-width: 62ch;
}

.page-about .qa-item__a p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted-light);
}

.page-about .qa-foot {
  margin-top: clamp(30px, 5vw, 44px);
  padding-top: 24px;
  border-top: 1px solid var(--about-line);
  display: grid;
  gap: 18px;
}

.page-about .qa-foot__text {
  margin: 0;
  max-width: 44ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted-light);
}

.page-about .qa-foot__links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .network__side {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 28px;
    align-items: start;
  }

  .page-about .region-filter {
    margin-top: 0;
    padding-top: 0;
    border-top: 0;
  }

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

  .page-about .panel-notes {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .qa-foot {
    grid-template-columns: 1fr auto;
    align-items: center;
  }
}

@media (min-width: 1024px) {
  .page-about .chapter__grid {
    grid-template-columns: minmax(220px, 0.72fr) minmax(0, 1.6fr);
    gap: clamp(40px, 6vw, 80px);
    align-items: start;
  }

  .page-about .chapter__grid .chapter__head {
    position: sticky;
    top: 96px;
  }

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

  .page-about .network {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .network__side {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .page-about .team {
    grid-template-columns: minmax(0, 1.7fr) minmax(240px, 1fr);
    align-items: start;
  }

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

  .page-about .team-cell--wide {
    grid-column: span 2;
  }

  .page-about .credit {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
    align-items: start;
  }
}