.page-about {
  --about-track: 80px;
  --about-line: 39px;
}

/* ---------- Hero ---------- */
.page-about .about-hero {
  padding-top: 1.5rem;
  padding-bottom: 3rem;
}

.page-about .about-hero .bh-breadcrumb {
  margin-bottom: 2.25rem;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.25rem;
}

.page-about .about-hero__title {
  margin: .75rem 0 1.25rem;
  font-size: clamp(2.25rem, 8vw, 4.75rem);
  line-height: 1.02;
  font-weight: 600;
  letter-spacing: -.02em;
  transform: skewX(-2deg);
  transform-origin: left top;
  color: var(--bh-paper);
}

.page-about .about-hero__lede {
  max-width: 60ch;
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--bh-muted);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .875rem;
  margin-top: 1.75rem;
}

.page-about .about-hero__aside {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 1px;
  background: var(--bh-line);
  border: 1px solid var(--bh-line);
  border-radius: var(--bh-radius);
  overflow: hidden;
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: .2rem;
  padding: 1.125rem 1rem;
  background: linear-gradient(160deg, var(--bh-ink-2), var(--bh-ink));
}

.page-about .about-stat__num {
  font-size: 2rem;
  line-height: 1;
  color: var(--bh-cyan);
  font-weight: 600;
}

.page-about .about-stat__unit {
  font-size: .75rem;
  letter-spacing: .14em;
  color: var(--bh-orange);
}

.page-about .about-stat__label {
  font-size: .8125rem;
  line-height: 1.5;
  color: var(--bh-muted);
}

.page-about .about-hero__media {
  margin: 3rem 0 0;
  border-radius: 0;
}

.page-about .about-hero__media img {
  filter: saturate(.45) brightness(.78);
}

/* ---------- Body spine ---------- */
.page-about .about-body {
  padding-bottom: 4rem;
}

.page-about .about-spine {
  position: relative;
  display: grid;
  gap: 3.5rem;
}

.page-about .about-node {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.125rem;
}

.page-about .about-node__track {
  display: flex;
  align-items: center;
  gap: .75rem;
}

.page-about .about-node__track::after {
  content: "";
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--bh-line), transparent);
}

.page-about .about-node__num {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  flex: 0 0 46px;
  border-radius: 50%;
  border: 1px solid var(--bh-line);
  background: var(--bh-black);
  font-size: .75rem;
  letter-spacing: .08em;
  color: var(--bh-muted);
  transition: border-color .35s var(--bh-ease), color .35s var(--bh-ease), box-shadow .35s var(--bh-ease);
}

.page-about .about-node.is-visible .about-node__num {
  border-color: var(--bh-cyan);
  color: var(--bh-cyan);
  box-shadow: 0 0 0 5px rgba(53, 230, 208, .07);
}

.page-about .about-node__kicker {
  margin: 0 0 .5rem;
  font-size: .75rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--bh-orange);
}

.page-about .about-node__title {
  margin: 0 0 1rem;
  font-family: var(--bh-font-display);
  font-size: clamp(1.625rem, 4.6vw, 2.5rem);
  font-weight: 600;
  line-height: 1.12;
  letter-spacing: -.01em;
  color: var(--bh-paper);
}

.page-about .about-node__copy p {
  margin: 0 0 1rem;
}

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

/* ---------- 02 处理流程 ---------- */
.page-about .about-process {
  display: grid;
  gap: 1.75rem;
  margin-top: 1.75rem;
}

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

.page-about .about-process__media img {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  filter: saturate(.4) brightness(.72);
}

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

.page-about .about-flow__item {
  padding: 1.125rem 1.25rem;
  background: var(--bh-ink);
  border-left: 2px solid transparent;
  transition: border-color .3s var(--bh-ease), background .3s var(--bh-ease);
}

.page-about .about-flow__item:hover {
  border-left-color: var(--bh-cyan);
  background: var(--bh-ink-2);
}

.page-about .about-flow__time {
  display: block;
  margin-bottom: .4rem;
  font-size: .75rem;
  letter-spacing: .12em;
  color: var(--bh-cyan);
}

.page-about .about-flow__text {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--bh-muted);
}

/* ---------- 03 团队 ---------- */
.page-about .about-team {
  display: grid;
  gap: 1.5rem;
  margin-top: 1.75rem;
}

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

.page-about .about-team__card {
  padding: 1.25rem 1.375rem;
}

.page-about .about-team__name {
  margin: 0 0 .55rem;
  font-family: var(--bh-font-display);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: .01em;
  color: var(--bh-paper);
}

.page-about .about-team__desc {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--bh-muted);
}

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

.page-about .about-team__media img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  filter: saturate(.38) brightness(.7);
}

/* ---------- 04 内容分类 ---------- */
.page-about .about-cats {
  display: grid;
  gap: 1rem;
  margin-top: 1.75rem;
}

.page-about .about-cat {
  position: relative;
  padding: 1.375rem 1.5rem;
  border-radius: var(--bh-radius-lg);
  border: 1px solid var(--bh-line);
  background: linear-gradient(155deg, var(--bh-ink-2), var(--bh-ink) 70%);
  transition: transform .3s var(--bh-ease), border-color .3s var(--bh-ease);
}

.page-about .about-cat:hover,
.page-about .about-cat:focus-within {
  transform: translateY(-4px);
  border-color: var(--bh-cyan);
}

.page-about .about-cat::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1.5rem;
  bottom: 1.5rem;
  width: 3px;
  border-radius: 3px;
}

.page-about .about-cat--a::before { background: var(--bh-cyan); }
.page-about .about-cat--b::before { background: var(--bh-orange); }
.page-about .about-cat--c::before { background: var(--bh-rose); }
.page-about .about-cat--d::before { background: var(--bh-gold); }
.page-about .about-cat--e::before { background: var(--bh-muted); }

.page-about .about-cat--a { min-height: 132px; }
.page-about .about-cat--b { min-height: 148px; }
.page-about .about-cat--c { min-height: 124px; }
.page-about .about-cat--d { min-height: 158px; }
.page-about .about-cat--e { min-height: 116px; }

.page-about .about-cat__name {
  margin: 0 0 .5rem;
  font-family: var(--bh-font-display);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--bh-paper);
}

.page-about .about-cat__desc {
  margin: 0 0 .75rem;
  font-size: .9375rem;
  line-height: 1.72;
  color: var(--bh-muted);
}

.page-about .about-cat__meta {
  margin: 0;
  font-family: var(--bh-font-mono);
  font-size: .75rem;
  letter-spacing: .05em;
  color: var(--bh-cyan);
}

/* ---------- 05 合作方 ---------- */
.page-about .about-partners {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1px;
  background: var(--bh-line);
  border: 1px solid var(--bh-line);
  border-radius: var(--bh-radius);
  overflow: hidden;
}

.page-about .about-partner {
  display: flex;
  flex-direction: column;
  gap: .5rem;
  padding: 1.25rem 1.125rem;
  background: var(--bh-ink);
  transition: background .3s var(--bh-ease);
}

.page-about .about-partner:hover {
  background: var(--bh-ink-2);
}

.page-about .about-partner p {
  margin: 0;
  font-size: .8125rem;
  line-height: 1.65;
  color: var(--bh-muted);
}

/* ---------- 06 里程碑标签页 ---------- */
.page-about .about-milestones {
  margin-top: 1.75rem;
  display: grid;
  gap: 1.25rem;
}

.page-about .about-milestones__list {
  display: grid;
  gap: .5rem;
}

.page-about .about-milestone__tab {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: .875rem;
  width: 100%;
  padding: .875rem 1rem;
  text-align: left;
  border-radius: var(--bh-radius);
  border: 1px solid var(--bh-line);
  background: var(--bh-ink);
  color: var(--bh-muted);
  cursor: pointer;
  transition: border-color .28s var(--bh-ease), background .28s var(--bh-ease), color .28s var(--bh-ease);
}

.page-about .about-milestone__tab:hover {
  border-color: var(--bh-cyan);
  color: var(--bh-paper);
}

.page-about .about-milestone__tab[aria-selected="true"] {
  background: var(--bh-ink-2);
  border-color: var(--bh-cyan);
  color: var(--bh-paper);
}

.page-about .about-milestone__num {
  font-size: .6875rem;
  letter-spacing: .14em;
  color: var(--bh-orange);
}

.page-about .about-milestone__label {
  font-family: var(--bh-font-display);
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: .01em;
}

.page-about .about-milestone__panel {
  padding: 1.5rem 1.5rem 1.625rem;
  border-radius: var(--bh-radius-lg);
  border: 1px solid var(--bh-line);
  border-left: 3px solid var(--bh-cyan);
  background: linear-gradient(150deg, var(--bh-ink-2), var(--bh-ink) 80%);
}

.page-about .about-milestone__title {
  margin: 0 0 .875rem;
  font-family: var(--bh-font-display);
  font-size: 1.3125rem;
  font-weight: 600;
  line-height: 1.3;
  color: var(--bh-paper);
}

.page-about .about-milestone__panel p {
  margin: 0 0 .875rem;
  font-size: .9375rem;
  line-height: 1.78;
  color: var(--bh-muted);
}

.page-about .about-milestone__gain {
  margin: 0 !important;
  padding-top: .875rem;
  border-top: 1px solid var(--bh-line);
  font-family: var(--bh-font-mono);
  font-size: .8125rem !important;
  color: var(--bh-cyan) !important;
}

/* ---------- 底部行动区 ---------- */
.page-about .about-cta {
  padding-bottom: 5rem;
}

.page-about .about-cta__inner {
  display: grid;
  gap: 1.5rem;
  padding: 2.25rem 1.5rem;
  border-radius: var(--bh-radius-lg);
  border: 1px solid var(--bh-line);
  background:
    radial-gradient(120% 140% at 100% 0%, rgba(53, 230, 208, .12), transparent 55%),
    linear-gradient(155deg, var(--bh-ink-2), var(--bh-black) 78%);
}

.page-about .about-cta__title {
  margin: .5rem 0 .875rem;
  font-family: var(--bh-font-display);
  font-size: clamp(1.5rem, 4.4vw, 2.125rem);
  font-weight: 600;
  line-height: 1.15;
  color: var(--bh-paper);
}

.page-about .about-cta__desc {
  margin: 0;
  max-width: 58ch;
  font-size: .9375rem;
  line-height: 1.8;
  color: var(--bh-muted);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .875rem;
}

.page-about .about-cta__link {
  font-size: .875rem;
  color: var(--bh-cyan);
  text-decoration: underline;
  text-underline-offset: 4px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-team__grid {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about .about-hero {
    padding-top: 2.5rem;
    padding-bottom: 4rem;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
    gap: 3.5rem;
    align-items: end;
  }

  .page-about .about-hero__media {
    margin-top: 4.5rem;
  }

  .page-about .about-spine {
    gap: 6.5rem;
  }

  .page-about .about-spine::before {
    content: "";
    position: absolute;
    left: var(--about-line);
    top: 0;
    bottom: 0;
    width: 1px;
    background: linear-gradient(180deg, transparent 0, var(--bh-line) 3%, var(--bh-line) 94%, transparent 100%);
    pointer-events: none;
  }

  .page-about .about-node {
    grid-template-columns: var(--about-track) minmax(0, 1fr);
    gap: 2.5rem;
    align-items: start;
  }

  .page-about .about-node__track {
    justify-content: center;
    gap: 0;
    padding-top: .25rem;
  }

  .page-about .about-node__track::after {
    display: none;
  }

  .page-about .about-process {
    grid-template-columns: minmax(0, 300px) minmax(0, 1fr);
    gap: 2.25rem;
    align-items: start;
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1fr) minmax(0, 340px);
    gap: 2rem;
    align-items: start;
  }

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

  .page-about .about-cats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    grid-auto-rows: minmax(120px, auto);
    align-items: stretch;
  }

  .page-about .about-cat--a { grid-row: span 2; }
  .page-about .about-cat--b { grid-row: span 3; }
  .page-about .about-cat--c { grid-row: span 2; }
  .page-about .about-cat--d { grid-row: span 3; }
  .page-about .about-cat--e { grid-row: span 2; }

  .page-about .about-milestones {
    grid-template-columns: minmax(0, 300px) minmax(0, 1fr);
    gap: 1.75rem;
    align-items: start;
  }

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

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 3fr) minmax(0, 2fr);
    align-items: center;
    gap: 2.5rem;
    padding: 3rem 2.75rem;
  }

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

@media (min-width: 1140px) {
  .page-about .about-cats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-cat--e { grid-column: span 2; }
}