.page-about {
  --ab-rail-w: 176px;
  --ab-gap: 56px;
  --ab-lit: var(--c-paper);
  background: var(--c-cream);
  color: var(--c-ink);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(40px, 6vw, 76px) 0 clamp(36px, 5vw, 64px);
  overflow: hidden;
}

.page-about .about-hero__block {
  position: absolute;
  top: 0;
  right: 0;
  width: min(46%, 600px);
  height: min(62%, 440px);
  background: linear-gradient(155deg, var(--c-red) 0%, var(--c-red-deep) 100%);
  clip-path: polygon(24% 0, 100% 0, 100% 100%, 0 100%);
  z-index: 0;
  pointer-events: none;
}

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

.page-about .about-hero__kicker {
  margin: 0 0 22px;
  color: var(--c-fog);
}

.page-about .about-hero__title {
  max-width: 11em;
  margin: 0;
  color: var(--c-ink);
}

.page-about .about-hero__lede {
  max-width: 42em;
  margin: 26px 0 0;
  color: var(--c-ink);
}

.page-about .about-hero__body {
  max-width: 40em;
  margin: 14px 0 0;
  color: var(--c-fog);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 30px;
}

.page-about .about-hero__figure {
  position: relative;
  z-index: 1;
  margin: clamp(36px, 5vw, 62px) auto 0;
}

.page-about .about-hero__figure .media__cap {
  display: block;
  margin-top: 12px;
}

/* ---------- 通用章节头 ---------- */
.page-about .about-head {
  max-width: 46em;
}

.page-about .about-head__title {
  margin: 14px 0 0;
}

.page-about .about-head__lede {
  margin: 18px 0 0;
  color: var(--c-ink);
}

/* ---------- 起点 ---------- */
.page-about .about-origin__title {
  margin: 14px 0 22px;
}

.page-about .about-origin__lead .t-body + .t-body {
  margin-top: 18px;
}

.page-about .about-origin__notes {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-top: 38px;
}

.page-about .about-note {
  border-top: 1px solid var(--line);
  padding-top: 16px;
}

.page-about .about-note .exhibit__no {
  color: var(--c-amber);
}

.page-about .about-note .exhibit__title {
  margin: 8px 0 10px;
}

/* ---------- 历程 ---------- */
.page-about .evolve {
  display: grid;
  grid-template-columns: var(--ab-rail-w) minmax(0, 1fr);
  gap: var(--ab-gap);
  margin-top: clamp(34px, 5vw, 56px);
}

.page-about .evolve__rail {
  position: sticky;
  top: calc(var(--topbar-h) + 24px);
  align-self: start;
}

.page-about .evolve__list {
  position: relative;
  margin: 0;
  padding: 4px 0 4px 20px;
  list-style: none;
}

.page-about .evolve__list::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 16px;
  bottom: 16px;
  width: 1px;
  background: linear-gradient(180deg, var(--c-amber) 0%, var(--c-bamboo) 55%, var(--line) 100%);
}

.page-about .evolve__link {
  position: relative;
  display: block;
  padding: 10px 8px 10px 0;
  text-decoration: none;
  color: var(--c-fog);
  transition: color 0.32s var(--ease);
}

.page-about .evolve__link::before {
  content: "";
  position: absolute;
  left: -20px;
  top: 16px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--c-bamboo);
  box-shadow: 0 0 0 3px var(--c-cream);
  transition: transform 0.32s var(--ease), background-color 0.32s var(--ease);
}

.page-about .evolve__link:hover,
.page-about .evolve__link:focus-visible {
  color: var(--c-red);
}

.page-about .evolve__link:hover::before,
.page-about .evolve__link:focus-visible::before {
  background: var(--c-red);
  transform: scale(1.4);
}

.page-about .evolve__year {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-13);
  letter-spacing: 0.04em;
  color: var(--c-amber);
}

.page-about .evolve__name {
  display: block;
  margin-top: 2px;
  font-size: var(--fs-15);
  line-height: 1.5;
}

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

.page-about .phase {
  margin: 0 -20px;
  padding: 22px 20px 30px;
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(var(--topbar-h) + 24px);
  transition: background-color 0.32s var(--ease);
}

.page-about .phase:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .phase__stamp {
  display: none;
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-13);
  color: var(--c-amber);
}

.page-about .phase__title {
  margin: 0 0 12px;
}

.page-about .phase--start:target,
.page-about .phase--site:target,
.page-about .phase--cols:target,
.page-about .phase--mobile:target,
.page-about .phase--refine:target {
  background: var(--ab-lit);
}

.page-about .evolve:has(.evolve__link--start:hover) .phase--start,
.page-about .evolve:has(.evolve__link--site:hover) .phase--site,
.page-about .evolve:has(.evolve__link--cols:hover) .phase--cols,
.page-about .evolve:has(.evolve__link--mobile:hover) .phase--mobile,
.page-about .evolve:has(.evolve__link--refine:hover) .phase--refine {
  background: var(--ab-lit);
}

/* 演化示意图 */
.page-about .evolve-map {
  margin-top: clamp(40px, 5vw, 64px);
  border-top: 1px solid var(--line);
  padding-top: 30px;
}

.page-about .evolve-map__svg {
  display: block;
  width: 100%;
  height: auto;
  max-height: 220px;
}

.page-about .evolve-map__seed {
  fill: var(--c-red);
}

.page-about .evolve-map__link {
  stroke: var(--c-amber);
  stroke-width: 1.5;
  stroke-dasharray: 5 7;
}

.page-about .evolve-map__dot {
  fill: var(--c-bamboo);
  opacity: 0.5;
}

.page-about .evolve-map__grid {
  fill: url(#aboutDotGrid);
}

.page-about .evolve-map__nodes {
  display: grid;
  gap: 12px;
  grid-template-columns: 1fr;
  margin-top: 22px;
}

.page-about .enode {
  border-top: 1px solid var(--line);
  padding-top: 12px;
}

.page-about .enode > summary {
  cursor: pointer;
  list-style: none;
  font-family: var(--font-serif);
  font-size: var(--fs-20);
  font-weight: 600;
  color: var(--c-ink);
}

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

.page-about .enode > summary::after {
  content: "＋";
  margin-left: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-15);
  color: var(--c-amber);
}

.page-about .enode[open] > summary::after {
  content: "－";
}

.page-about .enode p {
  margin: 10px 0 4px;
  font-size: var(--fs-15);
  line-height: 1.75;
  color: var(--c-fog);
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 22px 24px;
  margin-top: clamp(34px, 4vw, 52px);
}

.page-about .team-figure {
  grid-column: 8 / 13;
  grid-row: 1 / span 2;
  margin: 0;
  align-self: start;
}

.page-about .team-figure .media__cap {
  display: block;
  margin-top: 12px;
}

.page-about .team-block {
  border-top: 1px solid var(--line);
  padding-top: 16px;
}

.page-about .team-block .mono-label {
  color: var(--c-bamboo);
}

.page-about .team-block h3 {
  margin: 8px 0 10px;
}

.page-about .team-block--edit {
  grid-column: 1 / 7;
  grid-row: 1;
}

.page-about .team-block--tech {
  grid-column: 1 / 6;
  grid-row: 2;
  margin-top: 34px;
}

.page-about .team-block--cs {
  grid-column: 3 / 10;
  grid-row: 3;
  margin-top: 26px;
}

/* ---------- 内容 ---------- */
.page-about .cols-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px 36px;
  margin: clamp(34px, 4vw, 52px) 0 0;
  padding: 0;
  list-style: none;
}

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

.page-about .col-card:nth-child(even) {
  margin-top: 30px;
}

.page-about .col-card .exhibit__no {
  color: var(--c-amber);
}

.page-about .col-card .exhibit__title {
  margin: 8px 0 10px;
}

.page-about .col-card__meta {
  max-height: 0;
  margin: 0;
  overflow: hidden;
  opacity: 0;
  font-family: var(--font-mono);
  font-size: var(--fs-13);
  color: var(--c-clay);
  transition: max-height 0.32s var(--ease), opacity 0.32s var(--ease), margin-top 0.32s var(--ease);
}

.page-about .col-card:hover .col-card__meta,
.page-about .col-card:focus-within .col-card__meta {
  max-height: 40px;
  margin-top: 12px;
  opacity: 1;
}

.page-about .about-content__foot {
  margin-top: clamp(38px, 5vw, 58px);
  align-items: start;
}

.page-about .about-content__sub {
  margin: 0 0 14px;
}

.page-about .about-content__note {
  margin-top: 4px;
}

.page-about .about-content__note .t-sm {
  margin: 0;
  color: var(--c-fog);
}

.page-about .about-content__note a {
  color: var(--c-red);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 合作 ---------- */
.page-about .coop-grid {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: 48px;
  align-items: start;
}

.page-about .coop__title {
  margin: 14px 0 22px;
}

.page-about .coop__body .t-body + .t-body {
  margin-top: 18px;
}

.page-about .coop__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 26px;
}

.page-about .coop__figure {
  margin: 24px -28px 0 0;
}

.page-about .coop__figure .media__cap {
  display: block;
  margin-top: 12px;
}

/* ---------- 收束 ---------- */
.page-about .about-end {
  background: var(--c-ink);
  color: var(--c-cream);
}

.page-about .about-end__inner {
  max-width: 44em;
}

.page-about .about-end__label {
  margin: 0;
  color: var(--c-amber);
}

.page-about .about-end__title {
  margin: 14px 0 20px;
  color: var(--c-cream);
}

.page-about .about-end__text {
  margin: 0;
  color: rgba(251, 246, 238, 0.82);
}

.page-about .about-end__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 30px;
}

.page-about .about-end .btn--ghost {
  color: var(--c-cream);
  border-color: rgba(251, 246, 238, 0.42);
}

.page-about .about-end .btn--ghost:hover,
.page-about .about-end .btn--ghost:focus-visible {
  border-color: var(--c-amber);
  color: var(--c-amber);
}

/* ---------- 响应式 ---------- */
@media (hover: none) {
  .page-about .col-card__meta {
    max-height: 40px;
    margin-top: 12px;
    opacity: 1;
  }
}

@media (max-width: 1080px) {
  .page-about {
    --ab-rail-w: 148px;
    --ab-gap: 36px;
  }

  .page-about .team-figure {
    grid-column: 7 / 13;
  }

  .page-about .team-block--edit {
    grid-column: 1 / 7;
  }

  .page-about .team-block--tech {
    grid-column: 1 / 7;
  }

  .page-about .team-block--cs {
    grid-column: 1 / 8;
  }
}

@media (max-width: 860px) {
  .page-about .about-hero__block {
    width: 62%;
    height: 240px;
  }

  .page-about .about-hero__title {
    max-width: 14em;
  }

  .page-about .evolve {
    grid-template-columns: 1fr;
    gap: 26px;
  }

  .page-about .evolve__rail {
    position: static;
  }

  .page-about .evolve__list {
    display: flex;
    gap: 8px;
    padding: 0 0 8px;
    overflow-x: auto;
    scrollbar-width: thin;
  }

  .page-about .evolve__list::before {
    display: none;
  }

  .page-about .evolve__link {
    flex: 0 0 auto;
    padding: 8px 14px;
    border: 1px solid var(--line);
    white-space: nowrap;
  }

  .page-about .evolve__link::before {
    display: none;
  }

  .page-about .phase {
    margin: 0;
    padding: 20px 0 26px;
  }

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

  .page-about .team-grid {
    grid-template-columns: 1fr;
  }

  .page-about .team-figure,
  .page-about .team-block--edit,
  .page-about .team-block--tech,
  .page-about .team-block--cs {
    grid-column: 1 / -1;
    grid-row: auto;
    margin-top: 0;
  }

  .page-about .team-figure {
    margin-bottom: 8px;
  }

  .page-about .cols-list {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .page-about .col-card:nth-child(even) {
    margin-top: 0;
  }

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

  .page-about .coop__figure {
    margin: 0;
    max-width: 520px;
  }
}

@media (max-width: 560px) {
  .page-about .about-hero__block {
    width: 72%;
    height: 180px;
    clip-path: polygon(32% 0, 100% 0, 100% 100%, 0 100%);
  }

  .page-about .about-hero__title {
    max-width: none;
  }

  .page-about .about-hero__actions .btn,
  .page-about .about-end__actions .btn {
    flex: 1 1 100%;
    text-align: center;
  }

  .page-about .evolve-map__nodes {
    gap: 8px;
  }
}