.page-about {
  --about-rail: 250px;
  --about-gap: clamp(24px, 4vw, 64px);
  background: var(--ink-900);
  color: var(--text-bright);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(32px, 6vw, 72px) 0 clamp(44px, 7vw, 92px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -2;
  background:
    radial-gradient(52% 46% at 82% 10%, var(--cyan-08), transparent 68%),
    radial-gradient(42% 42% at 6% 92%, rgba(255, 138, 60, .06), transparent 72%),
    linear-gradient(180deg, var(--ink-800) 0%, var(--ink-900) 84%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(rgba(44, 75, 140, .14) 1px, transparent 1px),
    linear-gradient(90deg, rgba(44, 75, 140, .14) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-mask-image: radial-gradient(72% 68% at 52% 28%, #000 0%, transparent 100%);
  mask-image: radial-gradient(72% 68% at 52% 28%, #000 0%, transparent 100%);
  pointer-events: none;
}

.page-about .about-hero__inner {
  display: grid;
  gap: clamp(28px, 4vw, 56px);
  align-items: center;
}

.page-about .about-hero__title {
  margin: 12px 0 0;
  font-size: clamp(30px, 5.4vw, 56px);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: .02em;
}

.page-about .about-hero__lede {
  margin: 18px 0 0;
  max-width: 60ch;
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(24px, 3vw, 34px) 0 0;
  padding: 1px;
  background: rgba(44, 75, 140, .5);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.page-about .about-fact {
  background: var(--ink-900);
  padding: 14px 16px;
}

.page-about .about-fact dt {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--text-muted);
}

.page-about .about-fact dd {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(17px, 2vw, 21px);
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .about-hero__media {
  margin: 0;
  border-radius: var(--radius);
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  position: relative;
  padding: clamp(44px, 7vw, 96px) 0;
  border-top: 1px solid rgba(44, 75, 140, .45);
}

.page-about .chapter__grid {
  display: grid;
  gap: clamp(20px, 3vw, 36px);
}

.page-about .chapter__rail {
  position: relative;
}

.page-about .chapter__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(40px, 7vw, 74px);
  font-weight: 700;
  line-height: .9;
  letter-spacing: .02em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .chapter__title {
  margin: 12px 0 0;
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 900;
  line-height: 1.26;
  letter-spacing: .01em;
  color: var(--text-bright);
}

.page-about .chapter__annotation {
  display: none;
}

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

.page-about .chapter__lead {
  margin: 0;
  max-width: 68ch;
  font-size: clamp(17px, 1.5vw, 19px);
  line-height: 1.85;
  color: var(--text-bright);
}

.page-about .chapter__text {
  margin: 26px 0 0;
  max-width: 68ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--text-muted);
}

.page-about .chapter__figure {
  margin: 28px 0 0;
  max-width: 720px;
  border-radius: var(--radius);
}

.page-about .inline-link {
  color: var(--cyan);
  border-bottom: 1px solid var(--cyan-30);
  text-decoration: none;
  transition: border-color .2s var(--ease), color .2s var(--ease);
}

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

.page-about .note-line {
  margin: 26px 0 0;
  max-width: 68ch;
  padding-left: 14px;
  border-left: 2px solid var(--cyan);
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-muted);
}

/* ---------- 01 使用场景 ---------- */
.page-about .scene-list {
  list-style: none;
  display: grid;
  gap: 1px;
  margin: 28px 0 0;
  padding: 1px;
  background: rgba(44, 75, 140, .45);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .scene {
  background: var(--ink-900);
  padding: 22px 20px 24px;
  transition: background-color .2s var(--ease);
}

.page-about .scene:hover {
  background: var(--ink-800);
}

.page-about .scene__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--text-bright);
}

.page-about .scene__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-muted);
}

/* ---------- 02 版本线 ---------- */
.page-about .timeline {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 26px 28px;
  border-left: 1px solid var(--line-500);
}

.page-about .tl-item:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 5px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 2px solid var(--line-500);
  transition: border-color .2s var(--ease), box-shadow .2s var(--ease), background-color .2s var(--ease);
}

.page-about .tl-item:hover::before,
.page-about .tl-item:focus-within::before {
  border-color: var(--cyan);
  box-shadow: 0 0 0 4px var(--cyan-08);
}

.page-about .tl-item:last-child::before {
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .tl-item__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
}

.page-about .tl-item__ver {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .tl-item__name {
  font-size: 17px;
  font-weight: 700;
  color: var(--text-bright);
}

.page-about .tl-item__text {
  margin: 8px 0 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-muted);
  transition: color .2s var(--ease);
}

.page-about .tl-item:hover .tl-item__text {
  color: var(--text-bright);
}

/* ---------- 03 处理路径 ---------- */
.page-about .path-list {
  list-style: none;
  display: grid;
  gap: 16px;
  margin: 28px 0 0;
  padding: 0;
}

.page-about .path {
  display: flex;
  gap: 16px;
  padding: 20px 20px 22px;
  border: 1px solid var(--line-500);
  border-radius: var(--radius);
  background: var(--glass);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  transition: border-color .2s var(--ease), background-color .2s var(--ease);
}

.page-about .path:hover,
.page-about .path:focus-within {
  border-color: var(--cyan-30);
}

.page-about .path__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

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

.page-about .path__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  color: var(--text-bright);
}

.page-about .path__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-muted);
}

/* ---------- 04 团队 ---------- */
.page-about .team-grid {
  list-style: none;
  display: grid;
  gap: 1px;
  margin: 28px 0 0;
  padding: 1px;
  background: rgba(44, 75, 140, .5);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .team-card {
  background: var(--paper);
  color: var(--ink-800);
  padding: 24px 20px 26px;
}

.page-about .team-card__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 36px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: .02em;
  color: var(--ink-800);
  font-variant-numeric: tabular-nums;
}

.page-about .team-card__label {
  margin: 10px 0 0;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--ink-700);
}

.page-about .team-card__text {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--ink-800);
}

/* ---------- 05 资质与合作 ---------- */
.page-about .badge-grid {
  list-style: none;
  display: grid;
  gap: 14px;
  margin: 28px 0 0;
  padding: 0;
}

.page-about .badge {
  background: var(--paper);
  color: var(--ink-800);
  border-radius: var(--radius-sm);
  padding: 18px 16px 20px;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.6;
  transition: transform .2s var(--ease), box-shadow .2s var(--ease);
}

.page-about .badge:hover,
.page-about .badge:focus-within {
  transform: translateY(-4px);
  box-shadow: 0 14px 28px rgba(7, 20, 51, .5);
}

.page-about .badge__num {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .14em;
  color: var(--ink-700);
}

.page-about .partner-list {
  list-style: none;
  display: grid;
  gap: 0;
  margin: 30px 0 0;
  padding: 0;
}

.page-about .partner-item {
  padding: 18px 0;
  border-top: 1px solid rgba(44, 75, 140, .5);
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-muted);
}

.page-about .partner-item strong {
  display: inline-block;
  margin-right: 10px;
  font-weight: 700;
  color: var(--cyan);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  padding: clamp(36px, 6vw, 72px) 0 clamp(56px, 8vw, 104px);
}

.page-about .about-cta__panel {
  position: relative;
  overflow: hidden;
  padding: clamp(26px, 4vw, 52px);
  border: 1px solid var(--line-500);
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--ink-700) 0%, var(--ink-800) 62%, var(--ink-900) 100%);
}

.page-about .about-cta__panel::after {
  content: "";
  position: absolute;
  top: -40%;
  right: -12%;
  width: 46%;
  height: 180%;
  background: linear-gradient(90deg, transparent, var(--cyan-08), transparent);
  transform: rotate(6deg);
  pointer-events: none;
}

.page-about .about-cta__title {
  position: relative;
  margin: 0;
  max-width: 22ch;
  font-size: clamp(22px, 3vw, 34px);
  font-weight: 900;
  line-height: 1.3;
  letter-spacing: .01em;
  color: var(--text-bright);
}

.page-about .about-cta__text {
  position: relative;
  margin: 16px 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--text-muted);
}

.page-about .about-cta__actions {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .badge-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 760px) {
  .page-about .team-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .partner-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 32px;
  }
}

@media (min-width: 920px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
  }

  .page-about .chapter__grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
  }

  .page-about .chapter__rail {
    position: sticky;
    top: calc(var(--header-h) + 28px);
  }

  .page-about .chapter__annotation {
    display: block;
    margin: 20px 0 0;
    max-height: 150px;
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 12px;
    letter-spacing: .16em;
    color: var(--text-muted);
    white-space: nowrap;
  }
}