.page-about {
  --about-gap: 28px;
  --about-pad: 24px;
}

/* ---------- 面包屑与首屏 ---------- */

.page-about .breadcrumb {
  padding-top: 20px;
}

.page-about .about-hero {
  padding: 32px 0 40px;
  position: relative;
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -60px;
  top: 8px;
  width: 240px;
  height: 240px;
  border: 1px solid var(--line);
  border-radius: 50%;
  opacity: 0.5;
  pointer-events: none;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
}

.page-about .about-hero__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(44px, 13vw, 92px);
  letter-spacing: -0.02em;
  line-height: 1;
  margin: 14px 0 10px;
  color: var(--ink);
  transform: skewX(-3deg);
  transform-origin: left bottom;
}

.page-about .about-hero__sub {
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.6;
  color: var(--accent-soft);
  margin: 0 0 22px;
  padding-left: 12px;
  border-left: 2px solid var(--accent);
}

.page-about .about-hero__text p {
  font-size: 15px;
  line-height: 1.9;
  color: var(--ink);
  max-width: 46ch;
}

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

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

.page-about .about-hero__media .media-frame__cap {
  display: block;
  margin-top: 10px;
  color: var(--ink-2);
}

.page-about .about-hero__aside {
  color: var(--ink-2);
  border-top: 1px solid var(--line);
  padding-top: 12px;
}

/* ---------- 页内目录条 ---------- */

.page-about .about-toc {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--bg-1);
}

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

.page-about .about-toc__item {
  flex: 0 0 auto;
  border-right: 1px solid var(--line);
}

.page-about .about-toc__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 16px 20px;
  text-decoration: none;
  color: var(--ink-2);
  font-size: 14px;
  white-space: nowrap;
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-toc__idx {
  font-size: 12px;
  color: var(--line);
  transition: color var(--dur) var(--ease);
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  color: var(--accent);
  background: var(--bg-2);
}

.page-about .about-toc__link:hover .about-toc__idx,
.page-about .about-toc__link:focus-visible .about-toc__idx {
  color: var(--lime);
}

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

/* ---------- 通用区块与研究板 ---------- */

.page-about .about-section {
  padding: 56px 0;
}

.page-about .about-section--squad {
  padding-top: 68px;
}

.page-about .about-section--data {
  padding-top: 46px;
}

.page-about .about-section--team {
  padding-top: 62px;
}

.page-about .about-section--scope {
  padding-bottom: 72px;
}

.page-about .board {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .board__rule {
  display: none;
}

.page-about .board__main {
  border-left: 1px solid var(--line);
  padding-left: 18px;
}

.page-about .board__num {
  color: var(--accent);
  margin: 0 0 10px;
}

.page-about .board__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(24px, 6vw, 34px);
  line-height: 1.25;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
  color: var(--ink);
}

.page-about .board__lead {
  font-size: 15px;
  line-height: 1.9;
  color: var(--ink);
  max-width: 52ch;
  margin: 0 0 26px;
}

.page-about .board__detail {
  margin-top: 26px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.page-about .board__detail p {
  font-size: 15px;
  line-height: 1.9;
  color: var(--ink-2);
  max-width: 52ch;
  margin: 0 0 10px;
}

.page-about .board__detail-label {
  color: var(--lime);
  margin: 0 0 8px;
}

/* ---------- 建制段 ---------- */

.page-about .squad-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

.page-about .squad-figure {
  margin: 0;
  border: 1px solid var(--line);
}

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

.page-about .unit {
  display: grid;
  grid-template-columns: 62px 1fr;
  grid-template-areas:
    "code name"
    "code meta";
  gap: 2px 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
  transition: background-color var(--dur) var(--ease), padding-left var(--dur) var(--ease);
}

.page-about .unit:hover {
  background: var(--bg-1);
  padding-left: 10px;
}

.page-about .unit__code {
  grid-area: code;
  font-size: 24px;
  font-weight: 700;
  line-height: 1;
  color: var(--lime);
}

.page-about .unit__name {
  grid-area: name;
  font-size: 15px;
  color: var(--ink);
  line-height: 1.5;
}

.page-about .unit__meta {
  grid-area: meta;
  color: var(--ink-2);
  line-height: 1.6;
}

/* ---------- 流程与时间轴 ---------- */

.page-about .flow {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: flow;
}

.page-about .flow__step {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 0 14px;
  padding: 0 0 22px;
  border-left: 1px solid var(--line);
  margin-left: 6px;
  padding-left: 16px;
  position: relative;
}

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

.page-about .flow__idx {
  font-size: 20px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--accent);
  position: relative;
}

.page-about .flow__idx::before {
  content: "";
  position: absolute;
  left: -21px;
  top: 6px;
  width: 8px;
  height: 8px;
  background: var(--bg-0);
  border: 1px solid var(--accent);
}

.page-about .flow__title {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 16px;
  line-height: 1.5;
  margin: 4px 0 8px;
  color: var(--ink);
  letter-spacing: 0.01em;
}

.page-about .flow__text {
  font-size: 15px;
  line-height: 1.9;
  color: var(--ink-2);
  margin: 0;
  max-width: 50ch;
}

.page-about .axle-wrap {
  margin-top: 44px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}

.page-about .axle {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .axle__node {
  display: grid;
  grid-template-columns: 44px 1fr;
  grid-template-areas:
    "step name"
    "step desc";
  gap: 2px 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .axle__node:first-child {
  border-top: 1px solid var(--line);
}

.page-about .axle__step {
  grid-area: step;
  font-size: 14px;
  color: var(--line);
  transition: color var(--dur) var(--ease);
}

.page-about .axle__node:hover .axle__step {
  color: var(--lime);
}

.page-about .axle__name {
  grid-area: name;
  font-size: 16px;
  color: var(--ink);
  line-height: 1.5;
}

.page-about .axle__desc {
  grid-area: desc;
  color: var(--ink-2);
  line-height: 1.6;
}

/* ---------- 团队折叠组 ---------- */

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

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

.page-about .team-group__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 18px 0;
  cursor: pointer;
  list-style: none;
  transition: color var(--dur) var(--ease);
}

.page-about .team-group__head::-webkit-details-marker {
  display: none;
}

.page-about .team-group__head:hover .team-group__title {
  color: var(--accent);
}

.page-about .team-group__head:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.page-about .team-group__mark {
  flex: 0 0 14px;
  width: 14px;
  height: 14px;
  border: 1px solid var(--accent);
  position: relative;
  align-self: center;
}

.page-about .team-group__mark::before,
.page-about .team-group__mark::after {
  content: "";
  position: absolute;
  background: var(--accent);
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}

.page-about .team-group__mark::before {
  width: 8px;
  height: 1px;
}

.page-about .team-group__mark::after {
  width: 1px;
  height: 8px;
  transition: opacity var(--dur) var(--ease);
}

.page-about .team-group[open] .team-group__mark::after {
  opacity: 0;
}

.page-about .team-group__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 19px;
  letter-spacing: -0.01em;
  color: var(--ink);
  transition: color var(--dur) var(--ease);
}

.page-about .team-group__count {
  margin-left: auto;
  color: var(--ink-2);
}

.page-about .team-group__body {
  padding: 0 0 22px 28px;
}

.page-about .team-group__body p {
  font-size: 15px;
  line-height: 1.9;
  color: var(--ink-2);
  margin: 0 0 12px;
  max-width: 56ch;
}

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

/* ---------- 西南范围段 ---------- */

.page-about .region-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

.page-about .region-title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(24px, 6vw, 34px);
  line-height: 1.25;
  letter-spacing: -0.02em;
  margin: 12px 0 18px;
  color: var(--ink);
}

.page-about .region-text p {
  font-size: 15px;
  line-height: 1.9;
  color: var(--ink-2);
  margin: 0 0 16px;
  max-width: 54ch;
}

.page-about .region-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border-top: 1px solid var(--line);
}

.page-about .region-list__item {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .region-list__num {
  font-size: 32px;
  font-weight: 700;
  line-height: 1;
  color: var(--lime);
  min-width: 62px;
}

.page-about .region-list__label {
  font-size: 14px;
  line-height: 1.6;
  color: var(--ink);
}

.page-about .region-media {
  margin: 0;
}

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

.page-about .region-media .media-frame__cap {
  display: block;
  margin-top: 10px;
  color: var(--ink-2);
}

/* ---------- 口径与边界（窄栏收束） ---------- */

.page-about .scope-note {
  max-width: 68ch;
}

.page-about .scope-title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(22px, 5.5vw, 30px);
  line-height: 1.35;
  letter-spacing: -0.02em;
  margin: 12px 0 18px;
  color: var(--ink);
}

.page-about .scope-note > p {
  font-size: 15px;
  line-height: 2;
  color: var(--ink-2);
  margin: 0 0 26px;
}

.page-about .scope-inline-link {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid var(--accent);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .scope-inline-link:hover,
.page-about .scope-inline-link:focus-visible {
  color: var(--accent-soft);
  border-color: var(--accent-soft);
}

.page-about .scope-inline-link:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.page-about .scope-list {
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .scope-list__row {
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .scope-list__term {
  margin: 0 0 8px;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 16px;
  color: var(--ink);
}

.page-about .scope-list__def {
  margin: 0;
  font-size: 15px;
  line-height: 2;
  color: var(--ink-2);
}

.page-about .term {
  position: relative;
  display: inline-block;
  color: var(--accent);
  border-bottom: 1px dashed var(--line);
  cursor: help;
  outline-offset: 4px;
}

.page-about .term:focus-visible {
  outline: 2px solid var(--accent);
}

.page-about .term__def {
  position: absolute;
  left: 0;
  bottom: calc(100% + 10px);
  z-index: 4;
  width: min(260px, 72vw);
  display: none;
  padding: 10px 12px;
  background: var(--bg-2);
  border: 1px solid var(--accent);
  color: var(--ink);
  font-family: var(--font-sans);
  font-weight: 400;
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: 0.02em;
}

.page-about .term:hover .term__def,
.page-about .term:focus .term__def,
.page-about .term:focus-within .term__def {
  display: block;
}

.page-about .scope-boundary {
  margin-top: 36px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.page-about .scope-boundary__label {
  color: var(--stoppage);
  margin: 0 0 10px;
}

.page-about .scope-boundary p {
  font-size: 15px;
  line-height: 2;
  color: var(--ink-2);
  margin: 0 0 14px;
}

/* ---------- 收尾入口 ---------- */

.page-about .about-cta {
  border-top: 1px solid var(--line);
  background: var(--bg-1);
  padding: 44px 0 52px;
}

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

.page-about .about-cta__text {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(19px, 5vw, 24px);
  line-height: 1.5;
  letter-spacing: -0.01em;
  color: var(--ink);
  margin: 10px 0 0;
  max-width: 34ch;
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

/* ---------- 响应式 ---------- */

@media (min-width: 720px) {
  .page-about .about-hero {
    padding: 48px 0 56px;
  }

  .page-about .board__main {
    padding-left: 28px;
  }

  .page-about .flow__step {
    grid-template-columns: 52px 1fr;
    padding-left: 24px;
  }

  .page-about .flow__idx::before {
    left: -29px;
  }

  .page-about .axle {
    grid-template-columns: repeat(2, 1fr);
    column-gap: 32px;
  }

  .page-about .axle__node:nth-child(2) {
    border-top: 1px solid var(--line);
  }

  .page-about .region-list {
    grid-template-columns: repeat(3, 1fr);
    gap: 0 24px;
    border-top: 0;
  }

  .page-about .region-list__item {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    border-top: 1px solid var(--line);
    padding-top: 16px;
  }

  .page-about .about-cta__grid {
    grid-template-columns: 1fr auto;
    align-items: end;
    gap: 32px;
  }

  .page-about .about-cta__actions {
    justify-content: flex-end;
  }
}

@media (min-width: 980px) {
  .page-about .about-hero {
    padding: 56px 0 72px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: repeat(12, 1fr);
    column-gap: 24px;
    row-gap: 0;
    align-items: start;
  }

  .page-about .about-hero__lead {
    grid-column: 1 / 7;
  }

  .page-about .about-hero__media {
    grid-column: 8 / 12;
  }

  .page-about .about-hero__aside {
    grid-column: 12 / 13;
    writing-mode: vertical-rl;
    text-orientation: mixed;
    letter-spacing: 0.16em;
    border-top: 0;
    border-right: 1px solid var(--line);
    padding: 0 12px 0 0;
    margin-left: 0;
    align-self: start;
  }

  .page-about .about-section {
    padding: 76px 0;
  }

  .page-about .about-section--squad {
    padding-top: 84px;
  }

  .page-about .about-section--data {
    padding-top: 60px;
  }

  .page-about .about-section--team {
    padding-top: 88px;
  }

  .page-about .about-section--scope {
    padding-bottom: 96px;
  }

  .page-about .board__main {
    padding-left: 36px;
  }

  .page-about .squad-layout {
    grid-template-columns: repeat(12, 1fr);
    column-gap: 24px;
    align-items: start;
  }

  .page-about .squad-figure {
    grid-column: 1 / 5;
  }

  .page-about .squad-text {
    grid-column: 6 / 13;
  }

  .page-about .flow {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    column-gap: 40px;
    row-gap: 26px;
  }

  .page-about .flow__step {
    padding-bottom: 0;
  }

  .page-about .axle {
    grid-template-columns: repeat(4, 1fr);
    column-gap: 24px;
  }

  .page-about .axle__node {
    border-top: 1px solid var(--line);
    grid-template-columns: 34px 1fr;
  }

  .page-about .region-layout {
    grid-template-columns: repeat(12, 1fr);
    column-gap: 24px;
    align-items: start;
  }

  .page-about .region-text {
    grid-column: 1 / 8;
  }

  .page-about .region-media {
    grid-column: 9 / 13;
    margin-top: 64px;
  }

  .page-about .scope-note {
    max-width: 62ch;
    margin-left: 2%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc__link,
  .page-about .unit,
  .page-about .axle__step,
  .page-about .team-group__head,
  .page-about .team-group__title,
  .page-about .scope-inline-link {
    transition: none;
  }
}