.page-about {
  --about-sticky-top: 132px;
  --about-num-ghost: rgba(244, 247, 250, .15);
  background: var(--ink);
  color: var(--ice);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(24px, 5vw, 64px) 0 clamp(28px, 4vw, 56px);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(120% 90% at 88% -20%, rgba(215, 38, 61, .30), transparent 62%),
    radial-gradient(90% 80% at 4% 118%, rgba(34, 211, 238, .14), transparent 62%),
    linear-gradient(180deg, var(--ink) 0%, var(--carbon) 100%);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(115deg, rgba(244, 247, 250, .04) 0 1px, transparent 1px 26px);
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 40px);
}

.page-about .about-hero__title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2rem, 7vw, 3.6rem);
  line-height: .98;
  letter-spacing: -.01em;
  margin: 12px 0 0;
  text-transform: none;
}

.page-about .about-hero__lede {
  margin-top: 16px;
  max-width: 56ch;
  color: var(--mist);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.page-about .about-hero__aside {
  border: 1px solid var(--line);
  background: rgba(11, 13, 16, .72);
  padding: clamp(16px, 2.4vw, 24px);
}

.page-about .about-facts {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
}

.page-about .about-fact {
  background: rgba(21, 24, 29, .9);
  padding: 12px 14px;
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .about-fact__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 1.35rem;
  line-height: 1;
  color: var(--cyan);
  min-width: 72px;
}

.page-about .about-fact__unit {
  font-size: .75rem;
  margin-left: 3px;
  color: var(--cyan-soft);
}

.page-about .about-fact__label {
  font-size: .8125rem;
  color: var(--mist);
}

/* ---------- 外壳与索引 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}

.page-about .about-index {
  padding: 14px 0 10px;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-index .eyebrow {
  display: none;
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0 0 4px;
  display: flex;
  gap: 6px;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-index__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-index__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border: 1px solid var(--line);
  color: var(--mist);
  font-size: .8125rem;
  text-decoration: none;
  white-space: nowrap;
  transition: color .2s var(--ease), border-color .2s var(--ease), background-color .2s var(--ease);
}

.page-about .about-index__num {
  font-family: var(--font-mono);
  font-size: .6875rem;
  color: var(--red);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--ice);
  border-color: var(--line-strong);
  background: var(--carbon);
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  padding: clamp(32px, 5vw, 64px) 0;
  border-top: 1px solid var(--line-soft);
  scroll-margin-top: var(--about-sticky-top);
  transition: background-color .3s var(--ease);
}

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

.page-about .chapter:target {
  background: linear-gradient(90deg, rgba(215, 38, 61, .10), transparent 46%);
}

.page-about .chapter__head {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .chapter__num {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(2.8rem, 12vw, 4.2rem);
  line-height: .8;
  letter-spacing: -.02em;
  color: var(--about-num-ghost);
  margin: 0 0 4px;
}

.page-about .chapter__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.4rem, 4.4vw, 2.2rem);
  line-height: 1.12;
  letter-spacing: -.005em;
  margin: 6px 0 0;
}

.page-about .chapter__intro {
  color: var(--mist);
  max-width: 62ch;
  margin: 0 0 18px;
}

.page-about .chapter__text p {
  max-width: 66ch;
  color: var(--ice);
  margin: 0 0 14px;
}

.page-about .chapter__tail {
  margin-top: 6px;
}

.page-about .text-link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(34, 211, 238, .4);
  padding-bottom: 1px;
}

.page-about .text-link:hover,
.page-about .text-link:focus-visible {
  color: var(--cyan-soft);
  border-bottom-color: var(--cyan-soft);
}

.page-about .chapter__body--split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(18px, 3vw, 32px);
  align-items: start;
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
  background: var(--carbon);
}

.page-about .about-figure figcaption {
  margin-top: 8px;
  font-size: .75rem;
  letter-spacing: .04em;
  color: var(--mist);
}

/* ---------- 场景 ---------- */
.page-about .scene-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .scene {
  background: var(--carbon);
  padding: clamp(16px, 2.6vw, 26px);
}

.page-about .scene__tag {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: .01em;
  color: var(--ice);
}

.page-about .scene__tag::before {
  content: "";
  width: 16px;
  height: 2px;
  flex: none;
  background: var(--red);
}

.page-about .scene__text {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 原则 ---------- */
.page-about .principle-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .principle {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(138deg, rgba(142, 20, 36, .22), transparent 52%),
    var(--carbon);
  padding: clamp(18px, 2.8vw, 30px);
}

.page-about .principle::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 58px;
  height: 58px;
  background: linear-gradient(225deg, var(--red) 0 50%, transparent 50%);
  opacity: .85;
  pointer-events: none;
}

.page-about .principle__index {
  font-family: var(--font-mono);
  font-size: .6875rem;
  letter-spacing: .12em;
  color: var(--orange);
  margin: 0 0 10px;
}

.page-about .principle__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.35rem;
  line-height: 1.2;
  margin: 0 0 10px;
  color: var(--ice);
}

.page-about .principle__text {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.72;
  color: var(--mist);
  max-width: 46ch;
}

/* ---------- 数据条 ---------- */
.page-about .stat-strip {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .stat {
  position: relative;
  background: var(--ink);
  padding: 18px 14px 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .stat::after {
  content: "";
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 10px;
  height: 1px;
  background: var(--line);
  transition: background-color .25s var(--ease);
}

.page-about .stat:hover::after {
  background: var(--cyan);
}

.page-about .stat__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.5rem, 4.6vw, 2rem);
  line-height: 1;
  color: var(--cyan);
  white-space: nowrap;
}

.page-about .stat__unit {
  font-size: .8rem;
  margin-left: 2px;
  color: var(--cyan-soft);
}

.page-about .stat__label {
  font-size: .75rem;
  letter-spacing: .06em;
  color: var(--mist);
}

.page-about .stat-note {
  margin: 16px 0 0;
  font-size: .8125rem;
  line-height: 1.7;
  color: var(--mist);
  max-width: 66ch;
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 36px);
  align-items: start;
}

.page-about .role-list {
  list-style: none;
  margin: 0 0 20px;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .role {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr) 40px;
  align-items: center;
  gap: 10px;
}

.page-about .role__name {
  font-size: .8125rem;
  color: var(--ice);
}

.page-about .role__bar {
  display: block;
  height: 4px;
  background: var(--carbon-soft);
  border: 1px solid var(--line-soft);
}

.page-about .role__fill {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--red), var(--orange));
}

.page-about .role:nth-child(1) .role__fill { width: 39%; }
.page-about .role:nth-child(2) .role__fill { width: 35%; }
.page-about .role:nth-child(3) .role__fill { width: 17%; }
.page-about .role:nth-child(4) .role__fill { width: 9%; }

.page-about .role__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 1rem;
  color: var(--cyan);
  text-align: right;
}

.page-about .team-text {
  margin: 0 0 18px;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .chain {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
}

.page-about .chain li {
  display: flex;
  align-items: center;
  font-size: .8125rem;
  color: var(--ice);
  border: 1px solid var(--line);
  padding: 6px 12px;
  background: var(--carbon);
}

.page-about .chain li + li::before {
  content: "";
  width: 14px;
  height: 1px;
  background: var(--line-strong);
  margin: 0 8px;
  order: -1;
  margin-left: -22px;
}

.page-about .chain li + li {
  margin-left: 8px;
}

/* ---------- 时间线 ---------- */
.page-about .timeline-band {
  margin: 0 0 clamp(20px, 3vw, 32px);
}

.page-about .timeline-band img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 8 / 3;
  object-fit: cover;
  border: 1px solid var(--line);
  background: var(--carbon);
}

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 20px;
  border-left: 1px solid var(--line);
}

.page-about .tl {
  position: relative;
  padding: 0 0 clamp(20px, 3vw, 28px);
  outline: none;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: -23px;
  top: 7px;
  width: 6px;
  height: 6px;
  background: var(--red);
  box-shadow: 0 0 0 3px var(--ink);
  transition: background-color .2s var(--ease);
}

.page-about .tl__year {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 1rem;
  letter-spacing: .04em;
  color: var(--mist);
  margin: 0 0 4px;
  transition: color .2s var(--ease);
}

.page-about .tl__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.1rem;
  line-height: 1.3;
  margin: 0 0 4px;
  color: var(--ice);
}

.page-about .tl__text {
  margin: 0;
  font-size: .875rem;
  line-height: 1.7;
  color: var(--mist);
  max-width: 60ch;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: max-height .35s var(--ease), opacity .25s var(--ease), margin-top .25s var(--ease);
}

.page-about .tl:hover::before,
.page-about .tl:focus-visible::before,
.page-about .tl:focus-within::before {
  background: var(--cyan);
}

.page-about .tl:hover .tl__year,
.page-about .tl:focus-visible .tl__year,
.page-about .tl:focus-within .tl__year {
  color: var(--orange);
}

.page-about .tl:hover .tl__text,
.page-about .tl:focus-visible .tl__text,
.page-about .tl:focus-within .tl__text {
  max-height: 8em;
  opacity: 1;
  margin-top: 4px;
}

.page-about .tl--current::before {
  background: var(--orange);
}

.page-about .tl--current .tl__year {
  color: var(--orange);
}

/* 移动端与触屏：摘要直接可见 */
@media (hover: none) {
  .page-about .tl__text {
    max-height: none;
    opacity: 1;
    margin-top: 4px;
  }
}

/* ---------- 合作 ---------- */
.page-about .partner-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .partner-col {
  background: var(--carbon);
  padding: clamp(18px, 2.8vw, 30px);
}

.page-about .partner-col__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  margin: 0 0 16px;
  color: var(--ice);
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.page-about .partner-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .partner {
  display: grid;
  grid-template-columns: 52px minmax(0, 1fr);
  gap: 12px;
  align-items: start;
}

.page-about .partner__num,
.page-about .partner__year {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 1.35rem;
  line-height: 1.1;
  color: var(--orange);
}

.page-about .partner__year {
  font-size: .875rem;
  letter-spacing: .02em;
  color: var(--cyan);
}

.page-about .partner__text {
  font-size: .875rem;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .partner-contact {
  margin: 18px 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--line-soft);
  font-size: .875rem;
  color: var(--mist);
}

/* ---------- 收尾 ---------- */
.page-about .about-close {
  margin-top: clamp(20px, 4vw, 44px);
  padding: clamp(30px, 5vw, 60px) 0;
  border-top: 1px solid var(--line);
  background:
    radial-gradient(90% 150% at 8% 0%, rgba(215, 38, 61, .26), transparent 62%),
    radial-gradient(80% 130% at 96% 100%, rgba(34, 211, 238, .14), transparent 62%),
    var(--carbon);
}

.page-about .about-close__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  align-items: end;
}

.page-about .about-close__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.4rem, 4.6vw, 2.2rem);
  line-height: 1.1;
  margin: 8px 0 10px;
}

.page-about .about-close__text {
  margin: 0;
  color: var(--mist);
  max-width: 52ch;
}

.page-about .about-close__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 断点 ---------- */
@media (min-width: 720px) {
  .page-about .chapter__head {
    grid-template-columns: clamp(88px, 12vw, 132px) minmax(0, 1fr);
    column-gap: clamp(16px, 2.4vw, 28px);
    row-gap: 2px;
    align-items: end;
  }

  .page-about .chapter__num {
    grid-row: 1 / span 2;
    align-self: end;
    margin-bottom: 0;
    font-size: clamp(3.4rem, 8vw, 5.2rem);
  }

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

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

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

  .page-about .about-close__inner {
    grid-template-columns: minmax(0, 1.2fr) auto;
  }
}

@media (min-width: 900px) {
  .page-about .stat-strip {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, .6fr);
    align-items: end;
  }

  .page-about .chapter__body--split {
    grid-template-columns: minmax(0, .95fr) minmax(0, 1.05fr);
  }

  .page-about .team-grid {
    grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr);
  }
}

@media (min-width: 1024px) {
  .page-about .about-shell {
    grid-template-columns: 200px minmax(0, 1fr);
    column-gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: var(--about-sticky-top);
    padding: 48px 0 0;
    border-bottom: 0;
  }

  .page-about .about-index .eyebrow {
    display: block;
    margin: 0 0 14px;
  }

  .page-about .about-index__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding: 0;
  }

  .page-about .about-index__link {
    border: 0;
    border-left: 1px solid var(--line);
    padding: 9px 0 9px 14px;
    background: transparent;
    font-size: .875rem;
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    border-left-color: var(--cyan);
    background: transparent;
    color: var(--ice);
  }

  .page-about .stat-strip {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .page-about .chapter:first-child {
    padding-top: clamp(36px, 4vw, 56px);
  }
}

@media (min-width: 1280px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, .45fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl__text,
  .page-about .stat::after,
  .page-about .chapter {
    transition: none;
  }
}