.page-about {
  --about-line: var(--rule);
  --about-ink-soft: #3D4A54;
  --about-tick: rgba(150, 162, 171, .45);
  --about-amber-wash: rgba(214, 154, 45, .12);
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumbs {
  padding: 1.25rem 0 .25rem;
  font-size: var(--fs-14);
  color: #5B6871;
}

.page-about .breadcrumbs a {
  color: var(--blue-deep);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur-1) var(--ease);
}

.page-about .breadcrumbs a:hover {
  border-bottom-color: var(--blue);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 1.5rem 0 3rem;
  background:
    linear-gradient(180deg, rgba(233, 237, 240, .85), rgba(250, 251, 252, 0) 70%),
    repeating-linear-gradient(90deg, var(--about-tick) 0 1px, transparent 1px 80px);
  background-size: auto, 80px 100%;
  background-repeat: no-repeat, repeat;
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-hero__inner {
  display: grid;
  gap: 2rem;
}

.page-about .about-hero__title {
  margin: .75rem 0 0;
  font-family: var(--font-display);
  font-size: var(--fs-40);
  line-height: 1.06;
  letter-spacing: -.01em;
  text-transform: none;
  color: var(--ink);
}

.page-about .about-hero__lead .lede {
  margin-top: 1.25rem;
  max-width: 46ch;
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--about-ink-soft);
}

.page-about .about-hero__meta {
  margin-top: 1.25rem;
  font-size: var(--fs-14);
  color: var(--blue-deep);
  padding-left: .75rem;
  border-left: 3px solid var(--amber);
}

.page-about .about-hero__index {
  border-top: 1px solid var(--ink);
  padding-top: .875rem;
}

.page-about .about-hero__index-title {
  font-size: var(--fs-12);
  letter-spacing: .12em;
  color: var(--silver);
  margin: 0 0 .75rem;
}

.page-about .about-hero__index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: .5rem .875rem;
}

.page-about .about-hero__index-list a {
  display: flex;
  align-items: baseline;
  gap: .5rem;
  padding: .375rem 0;
  font-size: var(--fs-14);
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px dashed var(--about-line);
  transition: color var(--dur-1) var(--ease), border-color var(--dur-1) var(--ease);
}

.page-about .about-hero__index-list a:hover,
.page-about .about-hero__index-list a:focus-visible {
  color: var(--blue);
  border-bottom-color: var(--blue);
}

.page-about .about-hero__index-list .mono {
  font-size: var(--fs-12);
  color: var(--amber);
}

/* ---------- 通用小节 ---------- */
.page-about .about-roles,
.page-about .about-version,
.page-about .about-proof {
  padding: 3rem 0;
}

.page-about .about-path,
.page-about .about-eco,
.page-about .about-coop {
  padding: 3rem 0;
}

.page-about .eyebrow {
  font-size: var(--fs-12);
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--blue-deep);
  margin: 0 0 .875rem;
  padding-left: .625rem;
  border-left: 3px solid var(--blue);
}

.page-about .h-1 {
  font-family: var(--font-display);
  font-size: var(--fs-28);
  line-height: 1.2;
  letter-spacing: -.005em;
  color: var(--ink);
  margin: 0 0 1.25rem;
}

.page-about .h-2 {
  font-family: var(--font-display);
  font-size: var(--fs-21);
  line-height: 1.3;
  color: var(--ink);
  margin: 0 0 1rem;
}

.page-about .h-3 {
  font-size: var(--fs-17);
  font-weight: 700;
  color: var(--ink);
  margin: 0 0 .5rem;
}

.page-about .prose p {
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--about-ink-soft);
  max-width: 40ch;
  margin: 0 0 1.125rem;
}

.page-about .lede {
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--about-ink-soft);
  max-width: 48ch;
  margin: 0;
}

/* ---------- 团队构成 ---------- */
.page-about .about-roles__grid {
  display: grid;
  gap: 2rem;
}

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

.page-about .about-roles__media .media-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow-1);
}

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

.page-about .media-frame__tag {
  position: absolute;
  top: 0;
  left: 0;
  padding: .25rem .5rem;
  font-size: var(--fs-12);
  letter-spacing: .1em;
  background: var(--amber);
  color: var(--ink);
}

.page-about .media-frame__caption {
  display: block;
  margin-top: .625rem;
  font-size: var(--fs-12);
  color: var(--silver);
  padding-left: .5rem;
  border-left: 2px solid var(--rule);
}

/* ---------- 编研路径 ---------- */
.page-about .about-path {
  background: var(--panel);
  border-top: 1px solid var(--about-line);
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-path__head {
  max-width: 62ch;
  margin-bottom: 2.5rem;
}

.page-about .path-steps {
  list-style: none;
  margin: 0 0 2.5rem;
  padding: 0;
  display: grid;
  gap: 1.25rem;
  counter-reset: steps;
}

.page-about .path-step {
  position: relative;
  background: var(--white);
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  padding: 1.5rem 1.25rem 1.25rem;
  transition: border-color var(--dur-2) var(--ease), transform var(--dur-2) var(--ease), box-shadow var(--dur-2) var(--ease);
}

.page-about .path-step::before {
  content: "";
  position: absolute;
  top: 0;
  left: 1.25rem;
  right: 1.25rem;
  height: 3px;
  background: linear-gradient(90deg, var(--blue), rgba(14, 107, 168, 0));
  border-radius: 2px 2px 0 0;
}

.page-about .path-step:hover,
.page-about .path-step:focus-within {
  border-color: var(--blue);
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
}

.page-about .path-step__num {
  display: inline-block;
  font-size: var(--fs-14);
  color: var(--blue-deep);
  letter-spacing: .08em;
  margin-bottom: .5rem;
}

.page-about .path-step p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--about-ink-soft);
}

.page-about .about-path__media {
  margin: 0;
  max-width: 760px;
}

.page-about .about-path__media .media-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  background: var(--white);
  box-shadow: var(--shadow-1);
}

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

/* ---------- 版本留档 ---------- */
.page-about .about-version__grid {
  display: grid;
  gap: 2rem;
}

.page-about .about-version__aside {
  border-left: 3px solid var(--amber);
  padding-left: 1.125rem;
}

.page-about .about-version__stat {
  font-size: var(--fs-21);
  color: var(--ink);
  margin: 0 0 .5rem;
  letter-spacing: .02em;
}

.page-about .about-version__stat-note {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--silver);
  max-width: 26ch;
}

.page-about .about-version__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
  margin-top: 1.5rem;
}

/* ---------- 发展历程（深色） ---------- */
.page-about .about-history {
  background: var(--ink);
  color: var(--white);
  background-image:
    repeating-linear-gradient(90deg, rgba(150, 162, 171, .18) 0 1px, transparent 1px 80px);
}

.page-about .about-history .eyebrow--amber {
  color: var(--amber);
  border-left-color: var(--amber);
}

.page-about .about-history .h-1 {
  color: var(--white);
}

.page-about .about-history__head {
  max-width: 34ch;
  margin-bottom: 2.5rem;
}

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 1.75rem;
  position: relative;
  counter-reset: tl;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  top: .5rem;
  bottom: .5rem;
  left: .4375rem;
  width: 1px;
  background: linear-gradient(180deg, var(--amber), rgba(150, 162, 171, .25));
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 1.875rem 0;
  transition: transform var(--dur-2) var(--ease);
}

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: -1.75rem;
  top: .5rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--silver);
  transition: border-color var(--dur-2) var(--ease), background-color var(--dur-2) var(--ease), transform var(--dur-2) var(--ease);
}

.page-about .timeline__item:hover::before,
.page-about .timeline__item:focus-within::before {
  border-color: var(--amber);
  background: var(--amber);
  transform: scale(1.25);
}

.page-about .timeline__item:hover,
.page-about .timeline__item:focus-within {
  transform: translateX(2px);
}

.page-about .timeline__item--current::before {
  border-color: var(--blue);
  background: var(--blue);
}

.page-about .timeline__year {
  display: block;
  font-size: var(--fs-14);
  letter-spacing: .1em;
  color: var(--amber);
  margin-bottom: .375rem;
}

.page-about .timeline__item--current .timeline__year {
  color: var(--focus);
}

.page-about .timeline__body .h-3 {
  color: var(--white);
  margin: 0 0 .375rem;
}

.page-about .timeline__body p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--silver-soft);
  max-width: 48ch;
}

.page-about .about-history__note {
  margin: 2rem 0 0;
  max-width: 46ch;
}

.page-about .about-history .note--dark {
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--silver-soft);
  padding-left: .875rem;
  border-left: 2px solid var(--amber);
}

/* ---------- 合作生态 ---------- */
.page-about .about-eco {
  background: var(--white);
}

.page-about .about-eco__head {
  max-width: 60ch;
  margin-bottom: 2.25rem;
}

.page-about .eco-band {
  position: relative;
  margin: 0 0 2.25rem;
  background: var(--blue-deep);
  overflow: hidden;
  border-top: 1px solid var(--blue-deep);
  border-bottom: 1px solid var(--blue-deep);
}

.page-about .eco-band__media {
  position: absolute;
  inset: 0;
  opacity: .22;
}

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

.page-about .eco-band__inner {
  position: relative;
  display: grid;
  gap: 1.75rem;
  padding: 2.5rem 0;
}

.page-about .eco-band__stat {
  display: flex;
  flex-direction: column;
  gap: .375rem;
  border-left: 2px solid var(--amber);
  padding-left: 1rem;
}

.page-about .eco-band__num {
  font-size: var(--fs-40);
  line-height: 1;
  color: var(--white);
  letter-spacing: -.02em;
}

.page-about .eco-band__label {
  font-size: var(--fs-14);
  color: var(--silver-soft);
}

.page-about .about-eco__body .prose p {
  max-width: 44ch;
}

/* ---------- 机构对接 ---------- */
.page-about .about-coop {
  background: var(--panel);
  border-top: 1px solid var(--about-line);
}

.page-about .about-coop__head {
  margin-bottom: 2rem;
}

.page-about .coop-grid {
  display: grid;
  gap: 1.25rem;
  margin-bottom: 2.25rem;
}

.page-about .coop-card {
  position: relative;
  background: var(--white);
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  padding: 2rem 1.5rem 1.5rem;
  transition: border-color var(--dur-2) var(--ease), transform var(--dur-2) var(--ease), box-shadow var(--dur-2) var(--ease);
}

.page-about .coop-card:hover,
.page-about .coop-card:focus-within {
  border-color: var(--blue);
  transform: translateY(-2px);
  box-shadow: var(--shadow-2);
}

.page-about .coop-card__num {
  display: inline-block;
  font-size: var(--fs-14);
  font-weight: 700;
  color: var(--amber);
  letter-spacing: .08em;
  margin-bottom: .625rem;
}

.page-about .coop-card p {
  margin: 0 0 .75rem;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--about-ink-soft);
}

.page-about .coop-card__foot {
  margin: 0;
  font-size: var(--fs-12);
  letter-spacing: .04em;
  color: var(--blue-deep);
  padding-top: .75rem;
  border-top: 1px dashed var(--about-line);
}

.page-about .about-coop__cta {
  display: grid;
  gap: 1.25rem;
  background: var(--ink);
  color: var(--white);
  border-radius: var(--radius);
  padding: 1.75rem 1.5rem;
  border-left: 4px solid var(--amber);
}

.page-about .about-coop__cta .h-3 {
  color: var(--white);
  margin: 0 0 .5rem;
}

.page-about .about-coop__cta p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--silver-soft);
  max-width: 48ch;
}

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

/* ---------- 成果数字 ---------- */
.page-about .about-proof__inner {
  border-top: 1px solid var(--ink);
  padding-top: 1.75rem;
}

.page-about .about-proof__list {
  list-style: none;
  margin: 1.75rem 0;
  padding: 0;
  display: grid;
  gap: 1.25rem;
}

.page-about .about-proof__list li {
  display: flex;
  flex-direction: column;
  gap: .375rem;
  border-left: 2px solid var(--amber);
  padding-left: 1rem;
}

.page-about .about-proof__num {
  font-size: var(--fs-28);
  color: var(--ink);
  letter-spacing: -.02em;
  line-height: 1;
}

.page-about .about-proof__label {
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--about-ink-soft);
}

.page-about .about-proof__cta {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--about-ink-soft);
  max-width: 60ch;
}

.page-about .about-proof__cta a {
  color: var(--blue-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 按钮微调 ---------- */
.page-about .btn {
  display: inline-block;
  font-size: var(--fs-14);
  letter-spacing: .02em;
  padding: .625rem 1.25rem;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background-color var(--dur-1) var(--ease), color var(--dur-1) var(--ease), border-color var(--dur-1) var(--ease), transform var(--dur-1) var(--ease);
}

.page-about .btn:hover {
  transform: translateY(-2px);
}

.page-about .btn--primary {
  background: var(--blue);
  color: var(--white);
  border: 1px solid var(--blue);
}

.page-about .btn--primary:hover {
  background: var(--blue-deep);
  border-color: var(--blue-deep);
}

.page-about .btn--outline {
  background: transparent;
  color: var(--blue-deep);
  border: 1px solid var(--rule);
}

.page-about .btn--outline:hover {
  border-color: var(--blue);
  color: var(--blue);
}

.page-about .about-coop__cta .btn--primary {
  background: var(--blue);
  border-color: var(--blue);
  color: var(--white);
}

/* ---------- 焦点样式 ---------- */
.page-about a:focus-visible,
.page-about button:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero {
    padding: 2rem 0 4rem;
  }

  .page-about .about-hero__title {
    font-size: var(--fs-64);
  }

  .page-about .about-hero__inner {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }

  .page-about .about-hero__index-list {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .about-roles,
  .page-about .about-path,
  .page-about .about-version,
  .page-about .about-eco,
  .page-about .about-coop,
  .page-about .about-proof {
    padding: 4.5rem 0;
  }

  .page-about .about-roles__grid {
    grid-template-columns: 62% 34%;
    gap: 4%;
    align-items: start;
  }

  .page-about .path-steps {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
  }

  .page-about .about-version__grid {
    grid-template-columns: 30% 66%;
    gap: 4%;
    align-items: start;
  }

  .page-about .eco-band__inner {
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    padding: 3.5rem 0;
  }

  .page-about .coop-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
  }

  .page-about .about-coop__cta {
    grid-template-columns: 1fr auto;
    align-items: center;
    gap: 2rem;
    padding: 2rem;
  }

  .page-about .about-proof__list {
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
  }

  .page-about .h-1 {
    font-size: var(--fs-40);
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 1040px) {
  .page-about .about-hero__inner {
    grid-template-columns: 58% 38%;
    gap: 4%;
    align-items: end;
  }

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

  .page-about .about-roles__grid {
    grid-template-columns: 58% 38%;
    gap: 4%;
  }

  .page-about .path-steps {
    grid-template-columns: repeat(6, 1fr);
    gap: 1.125rem;
  }

  .page-about .path-step {
    padding: 1.75rem 1rem 1.25rem;
  }

  .page-about .timeline {
    padding-left: 2.25rem;
  }

  .page-about .timeline__item {
    padding-bottom: 2.25rem;
  }

  .page-about .timeline__item::before {
    left: -2.25rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 1ms !important;
  }

  .page-about .path-step:hover,
  .page-about .path-step:focus-within,
  .page-about .coop-card:hover,
  .page-about .coop-card:focus-within,
  .page-about .btn:hover,
  .page-about .timeline__item:hover,
  .page-about .timeline__item:focus-within {
    transform: none;
  }
}
</main>