.page-about {
  --about-rail: clamp(13rem, 22vw, 19rem);
  --about-gap: clamp(1.75rem, 4.5vw, 3.25rem);
  color: var(--c-ink);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  background: var(--c-paper);
  padding-top: clamp(1rem, 2.5vw, 1.5rem);
}

.page-about .breadcrumb__link {
  color: var(--c-ink-soft);
  text-decoration: none;
}

.page-about .breadcrumb__link:hover,
.page-about .breadcrumb__link:focus-visible {
  color: var(--c-home-leaf);
}

.page-about .breadcrumb__current {
  color: var(--c-ink);
  font-weight: 600;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background: var(--c-home-deep);
  color: var(--c-card);
  padding: clamp(1.75rem, 5vw, 3.25rem) 0 clamp(2.5rem, 7vw, 5rem);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(251, 249, 244, .07) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(251, 249, 244, .07) 1px, transparent 1px);
  background-size: 72px 72px;
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -220px;
  right: -160px;
  width: min(560px, 78vw);
  aspect-ratio: 1;
  background: radial-gradient(circle, rgba(228, 87, 46, .36), transparent 66%);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(2rem, 5vw, 3.5rem);
}

.page-about .about-hero__text .eyebrow {
  color: var(--c-data-cyan);
}

.page-about .about-hero__text h1 {
  margin: .6rem 0 1rem;
  font-family: var(--font-head);
  font-size: clamp(2.1rem, 5.4vw, 4.1rem);
  line-height: 1.06;
  letter-spacing: -.02em;
  font-weight: 800;
  color: var(--c-card);
}

.page-about .about-hero__text .lede {
  max-width: 42ch;
  color: rgba(251, 249, 244, .82);
  font-size: clamp(1rem, 1.5vw, 1.1rem);
  line-height: 1.8;
}

.page-about .about-hero__tags {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-hero__tags .label {
  background: rgba(251, 249, 244, .08);
  border: 1px solid var(--c-line-invert);
  color: rgba(251, 249, 244, .9);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  margin-top: 1.75rem;
}

.page-about .about-hero .btn--ghost {
  color: var(--c-card);
  border-color: rgba(251, 249, 244, .35);
}

.page-about .about-hero .btn--ghost:hover,
.page-about .about-hero .btn--ghost:focus-visible {
  background: rgba(251, 249, 244, .12);
  border-color: var(--c-card);
}

.page-about .about-hero__frame {
  border-radius: var(--r-lg);
  overflow: hidden;
  box-shadow: var(--sh-2);
}

.page-about .about-hero__frame img {
  max-width: 100%;
  height: auto;
  object-fit: cover;
  display: block;
}

.page-about .about-hero__numbers {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: .75rem;
  margin: 1.5rem 0 0;
  padding-top: 1.25rem;
  border-top: 1px solid var(--c-line-invert);
}

.page-about .about-hero__numbers dt {
  font-size: .72rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: rgba(251, 249, 244, .58);
  margin-bottom: .35rem;
}

.page-about .about-hero__numbers dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 1.05rem;
  color: var(--c-card);
}

.page-about .about-hero__numbers .stat-num,
.page-about .about-quality__stat .stat-num,
.page-about .about-role__num .stat-num,
.page-about .about-network__facts .stat-num {
  font-family: var(--font-mono);
  font-weight: 700;
}

/* ---------- 通用章节：左右分屏 ---------- */
.page-about .about-chapter__grid {
  display: grid;
  gap: var(--about-gap);
  align-items: start;
}

.page-about .about-chapter__rail h2 {
  margin: .6rem 0 0;
  font-family: var(--font-head);
  font-size: clamp(1.5rem, 3vw, 2.15rem);
  line-height: 1.24;
  letter-spacing: -.01em;
  color: var(--c-ink);
}

.page-about .about-chapter__body p {
  margin: 0 0 1.15rem;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--c-ink-soft);
}

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

.page-about .about-chapter__figure {
  margin-top: 2rem;
  border-radius: var(--r-lg);
  overflow: hidden;
  box-shadow: var(--sh-1);
}

.page-about .about-chapter__figure img,
.page-about .about-flow__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 团队构成 ---------- */
.page-about .about-team {
  background: var(--c-paper);
}

.page-about .about-team__head {
  margin-bottom: clamp(1.75rem, 4vw, 2.75rem);
}

.page-about .about-team__grid {
  display: grid;
  gap: 1rem;
}

.page-about .about-role {
  position: relative;
  padding: 1.4rem 1.4rem 1.5rem;
  background: var(--c-card);
  border: 1px solid var(--c-line-soft);
  border-left: 4px solid var(--c-stone);
  border-radius: var(--r-md);
  transition: transform .35s var(--ease), box-shadow .35s var(--ease);
}

.page-about .about-role:hover,
.page-about .about-role:focus-within {
  transform: translateY(-4px);
  box-shadow: var(--sh-1);
}

.page-about .about-role--lead {
  border-left-color: var(--c-home-deep);
  background: linear-gradient(160deg, rgba(31, 107, 74, .1), rgba(251, 249, 244, 0) 62%), var(--c-card);
}

.page-about .about-role:nth-child(2) {
  border-left-color: var(--c-data-blue);
}

.page-about .about-role:nth-child(3) {
  border-left-color: var(--c-terra);
}

.page-about .about-role:nth-child(4) {
  border-left-color: var(--c-away-flame);
}

.page-about .about-role__num {
  display: flex;
  align-items: baseline;
  gap: .25rem;
  margin: 0 0 .35rem;
  font-family: var(--font-mono);
  font-size: clamp(2rem, 5vw, 2.9rem);
  line-height: 1;
  color: var(--c-home-deep);
  letter-spacing: -.02em;
}

.page-about .about-role__unit {
  font-size: .9rem;
  font-family: var(--font-body);
  color: var(--c-ink-mute);
}

.page-about .about-role__name {
  margin: 0 0 .6rem;
  font-family: var(--font-head);
  font-size: 1.15rem;
  letter-spacing: .02em;
  color: var(--c-ink);
}

.page-about .about-role__desc {
  margin: 0;
  font-size: .95rem;
  line-height: 1.8;
  color: var(--c-ink-soft);
}

.page-about .about-role__list {
  margin: 1rem 0 0;
  padding: 1rem 0 0;
  list-style: none;
  border-top: 1px dashed var(--c-line);
  display: grid;
  gap: .5rem;
}

.page-about .about-role__list li {
  position: relative;
  padding-left: 1.1rem;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--c-ink-soft);
}

.page-about .about-role__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--c-home-leaf);
}

/* ---------- 数据运营流程 ---------- */
.page-about .about-flow__hint {
  margin: 1rem 0 0;
  font-size: .95rem;
  line-height: 1.8;
  color: var(--c-ink-mute);
}

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

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

.page-about .about-flow__step summary {
  display: flex;
  align-items: baseline;
  gap: .85rem;
  padding: 1.05rem .2rem;
  list-style: none;
  cursor: pointer;
  font-family: var(--font-head);
  font-size: 1.08rem;
  font-weight: 700;
  color: var(--c-ink);
  transition: color .25s var(--ease);
}

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

.page-about .about-flow__step summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 1.25rem;
  color: var(--c-data-blue);
  line-height: 1;
}

.page-about .about-flow__step[open] summary::after {
  content: "\2212";
}

.page-about .about-flow__step summary:hover,
.page-about .about-flow__step summary:focus-visible {
  color: var(--c-home-leaf);
}

.page-about .about-flow__no {
  font-size: .85rem;
  letter-spacing: .12em;
  color: var(--c-data-blue);
}

.page-about .about-flow__step .accordion__body {
  padding: 0 0 1.25rem 2.1rem;
}

.page-about .about-flow__step .accordion__body p {
  margin: 0;
  font-size: .95rem;
  line-height: 1.85;
  color: var(--c-ink-soft);
}

.page-about .about-flow__figure {
  margin-top: 2rem;
  border-radius: var(--r-lg);
  overflow: hidden;
  box-shadow: var(--sh-1);
}

/* ---------- 更新节奏 ---------- */
.page-about .about-quality {
  padding-top: clamp(2rem, 5vw, 3.5rem);
  padding-bottom: clamp(2rem, 5vw, 3.5rem);
}

.page-about .about-quality__panel {
  padding: clamp(1.5rem, 4vw, 3rem);
  border-radius: var(--r-xl);
  background: var(--c-card);
  border: 1px solid var(--c-line-soft);
  box-shadow: var(--sh-1);
}

.page-about .about-quality__head h2 {
  margin: .6rem 0 .9rem;
  font-family: var(--font-head);
  font-size: clamp(1.5rem, 3vw, 2.15rem);
  line-height: 1.24;
  letter-spacing: -.01em;
  color: var(--c-ink);
}

.page-about .about-quality__lede {
  margin: 0;
  max-width: 62ch;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--c-ink-soft);
}

.page-about .about-quality__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin: clamp(1.5rem, 4vw, 2.25rem) 0 0;
  padding-top: clamp(1.25rem, 3vw, 2rem);
  border-top: 1px solid var(--c-line);
}

.page-about .about-quality__stat {
  display: flex;
  flex-direction: column-reverse;
  gap: .3rem;
  padding: .85rem 1rem;
  border-radius: var(--r-sm);
  background: var(--c-paper);
}

.page-about .about-quality__stat dt {
  font-size: .78rem;
  letter-spacing: .06em;
  color: var(--c-ink-mute);
}

.page-about .about-quality__stat dd {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: .25rem;
  font-size: clamp(1.6rem, 4vw, 2.3rem);
  line-height: 1;
  color: var(--c-home-deep);
}

.page-about .about-unit {
  font-family: var(--font-body);
  font-size: .85rem;
  color: var(--c-ink-mute);
}

.page-about .about-quality__checks {
  display: grid;
  gap: .6rem;
  margin: clamp(1.5rem, 3vw, 2rem) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-quality__checks li {
  position: relative;
  padding-left: 1.5rem;
  font-size: .95rem;
  line-height: 1.75;
  color: var(--c-ink-soft);
}

.page-about .about-quality__checks li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .58em;
  width: 9px;
  height: 9px;
  border-radius: 2px;
  background: var(--c-data-blue);
}

/* ---------- 发展历程 ---------- */
.page-about .about-timeline {
  position: relative;
  background: var(--c-home-shadow);
  color: var(--c-card);
  overflow: hidden;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(251, 249, 244, .05) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(251, 249, 244, .05) 1px, transparent 1px);
  background-size: 64px 64px;
  pointer-events: none;
}

.page-about .about-timeline > .wrap {
  position: relative;
  z-index: 1;
}

.page-about .about-timeline__head .lede {
  color: rgba(251, 249, 244, .74);
  max-width: 56ch;
}

.page-about .about-timeline__head h2 {
  margin: .6rem 0 .9rem;
  font-family: var(--font-head);
  font-size: clamp(1.5rem, 3vw, 2.15rem);
  line-height: 1.24;
  color: var(--c-card);
}

.page-about .about-timeline__head .label--invert {
  background: rgba(251, 249, 244, .1);
  border: 1px solid var(--c-line-invert);
  color: var(--c-data-cyan);
}

.page-about .about-timeline__filter {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin: clamp(1.25rem, 3vw, 2rem) 0 .75rem;
}

.page-about .about-timeline__filter .filter-btn {
  font-family: var(--font-mono);
  font-size: .82rem;
  letter-spacing: .06em;
  padding: .45rem .95rem;
  border-radius: 999px;
  border: 1px solid var(--c-line-invert);
  background: rgba(251, 249, 244, .06);
  color: rgba(251, 249, 244, .8);
  cursor: pointer;
  transition: background .25s var(--ease), color .25s var(--ease), border-color .25s var(--ease);
}

.page-about .about-timeline__filter .filter-btn:hover,
.page-about .about-timeline__filter .filter-btn:focus-visible {
  border-color: var(--c-data-cyan);
  color: var(--c-card);
}

.page-about .about-timeline__filter .filter-btn[aria-pressed="true"] {
  background: var(--c-away-flame);
  border-color: var(--c-away-flame);
  color: #fff;
}

.page-about .about-timeline__status {
  margin: 0 0 1.5rem;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .08em;
  color: rgba(251, 249, 244, .5);
}

.page-about .about-timeline__list {
  display: grid;
  gap: 1rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-timeline__item {
  position: relative;
  padding: 1.15rem 1.25rem 1.25rem;
  border-radius: var(--r-md);
  border: 1px solid var(--c-line-invert);
  border-left: 3px solid var(--c-home-leaf);
  background: rgba(251, 249, 244, .06);
  transition: transform .35s var(--ease), background .35s var(--ease);
}

.page-about .about-timeline__item:hover {
  transform: translateX(4px);
  background: rgba(251, 249, 244, .1);
}

.page-about .about-timeline__item--data {
  border-left-color: var(--c-data-cyan);
}

.page-about .about-timeline__item--away {
  border-left-color: var(--c-away-flame);
}

.page-about .about-timeline__item--terra {
  border-left-color: var(--c-terra);
}

.page-about .about-timeline__year {
  margin: 0 0 .4rem;
  font-size: .82rem;
  letter-spacing: .16em;
  color: var(--c-data-cyan);
}

.page-about .about-timeline__title {
  margin: 0 0 .5rem;
  font-family: var(--font-head);
  font-size: 1.08rem;
  color: var(--c-card);
}

.page-about .about-timeline__desc {
  margin: 0;
  font-size: .92rem;
  line-height: 1.78;
  color: rgba(251, 249, 244, .74);
}

/* ---------- 协作生态 ---------- */
.page-about .about-network__grid {
  display: grid;
  gap: var(--about-gap);
  align-items: start;
}

.page-about .about-network__text h2 {
  margin: .6rem 0 1rem;
  font-family: var(--font-head);
  font-size: clamp(1.5rem, 3vw, 2.15rem);
  line-height: 1.24;
  letter-spacing: -.01em;
  color: var(--c-ink);
}

.page-about .about-network__text p {
  margin: 0 0 1.15rem;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--c-ink-soft);
}

.page-about .about-network__links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.page-about .about-network__links .link {
  position: relative;
  color: var(--c-data-blue);
  text-decoration: none;
  font-weight: 600;
  padding-bottom: 2px;
  border-bottom: 2px solid rgba(31, 111, 235, .28);
  transition: border-color .25s var(--ease), color .25s var(--ease);
}

.page-about .about-network__links .link:hover,
.page-about .about-network__links .link:focus-visible {
  color: var(--c-away-flame);
  border-bottom-color: var(--c-away-flame);
}

.page-about .about-network__card {
  padding: clamp(1.25rem, 3vw, 1.75rem);
  border-radius: var(--r-lg);
  background: var(--c-card);
  border: 1px solid var(--c-line-soft);
  box-shadow: var(--sh-1);
}

.page-about .about-network__card-label {
  margin: 0 0 1rem;
  font-size: .72rem;
  letter-spacing: .2em;
  color: var(--c-stone);
}

.page-about .about-network__facts {
  display: grid;
  gap: .9rem;
  margin: 0;
}

.page-about .about-network__facts > div {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: .75rem;
  border-bottom: 1px dashed var(--c-line);
}

.page-about .about-network__facts > div:last-child {
  padding-bottom: 0;
  border-bottom: 0;
}

.page-about .about-network__facts dt {
  font-size: .85rem;
  color: var(--c-ink-mute);
}

.page-about .about-network__facts dd {
  margin: 0;
  font-size: 1.05rem;
  color: var(--c-home-deep);
  white-space: nowrap;
}

/* ---------- 结尾 CTA ---------- */
.page-about .about-cta {
  padding-bottom: clamp(2.5rem, 6vw, 4.5rem);
}

.page-about .about-cta__inner {
  display: grid;
  gap: 1.75rem;
  padding: clamp(1.75rem, 4.5vw, 3rem);
  border-radius: var(--r-xl);
  background: linear-gradient(120deg, var(--c-home-deep), var(--c-home-shadow) 62%, var(--c-away-clay));
  color: var(--c-card);
  box-shadow: var(--sh-2);
}

.page-about .about-cta__text h2 {
  margin: .6rem 0 .9rem;
  font-family: var(--font-head);
  font-size: clamp(1.5rem, 3.2vw, 2.2rem);
  line-height: 1.2;
  color: var(--c-card);
}

.page-about .about-cta__text p {
  margin: 0;
  max-width: 56ch;
  font-size: 1rem;
  line-height: 1.8;
  color: rgba(251, 249, 244, .8);
}

.page-about .about-cta__text .label--invert {
  background: rgba(251, 249, 244, .12);
  border: 1px solid var(--c-line-invert);
  color: var(--c-data-cyan);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
}

.page-about .about-cta .btn--ghost {
  color: var(--c-card);
  border-color: rgba(251, 249, 244, .35);
}

.page-about .about-cta .btn--ghost:hover,
.page-about .about-cta .btn--ghost:focus-visible {
  background: rgba(251, 249, 244, .12);
  border-color: var(--c-card);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-team__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .about-timeline__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.25rem;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero__inner {
    grid-template-columns: 7fr 5fr;
    align-items: center;
  }

  .page-about .about-chapter__grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(2.25rem, 6vw, 4.5rem);
  }

  .page-about .about-chapter__rail {
    position: sticky;
    top: 6.5rem;
    align-self: start;
  }

  .page-about .about-network__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: clamp(2.25rem, 5vw, 4rem);
  }

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: 2.5rem;
  }

  .page-about .about-cta__actions {
    flex-direction: column;
    align-items: stretch;
  }
}

@media (min-width: 1024px) {
  .page-about .about-team__grid {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: 1.25rem;
  }

  .page-about .about-role--lead {
    grid-column: 1 / span 5;
  }

  .page-about .about-role:nth-child(2) {
    grid-column: 6 / span 7;
  }

  .page-about .about-role:nth-child(3) {
    grid-column: 1 / span 7;
  }

  .page-about .about-role:nth-child(4) {
    grid-column: 8 / span 5;
  }
}

@media (max-width: 519px) {
  .page-about .about-hero__numbers {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    row-gap: 1rem;
  }

  .page-about .about-flow__step .accordion__body {
    padding-left: .2rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-role,
  .page-about .about-timeline__item,
  .page-about .about-timeline__filter .filter-btn {
    transition: none;
  }

  .page-about .about-role:hover,
  .page-about .about-role:focus-within {
    transform: none;
  }

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