.page-about {
  --about-rail: 216px;
  --about-gap: clamp(24px, 4vw, 56px);
  position: relative;
  padding-top: clamp(80px, 11vw, 128px);
  padding-bottom: clamp(48px, 7vw, 88px);
  background:
    radial-gradient(900px 420px at 12% -4%, rgba(139, 92, 246, 0.18), transparent 70%),
    radial-gradient(700px 380px at 92% 6%, rgba(56, 189, 248, 0.10), transparent 72%),
    linear-gradient(180deg, var(--ink-050) 0%, var(--bg) 46%);
  color: var(--text);
}

.page-about a {
  color: var(--blue);
  text-decoration: none;
}

.page-about a:hover {
  color: var(--violet-soft);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb-wrap {
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-dim);
}

.page-about .breadcrumb a {
  color: var(--text-dim);
}

.page-about .breadcrumb a:hover {
  color: var(--violet-soft);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero-inner {
  display: grid;
  gap: 18px;
  max-width: 940px;
}

.page-about .about-kicker {
  margin: 0;
  display: inline-block;
  align-self: start;
  padding: 6px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: rgba(139, 92, 246, 0.12);
  color: var(--violet-soft);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.page-about h1 {
  margin: 0;
  font-size: clamp(30px, 6.4vw, 62px);
  line-height: 1.04;
  font-weight: 900;
  letter-spacing: -0.022em;
  color: var(--white);
}

.page-about .about-hero .lede {
  margin: 0;
  max-width: 64ch;
  color: var(--text-dim);
  font-size: clamp(15.5px, 2vw, 18px);
  line-height: 1.9;
}

.page-about .about-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 10px 0 0;
  padding: 0;
  list-style: none;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-hero-stats li {
  display: grid;
  gap: 4px;
  padding: 14px 16px;
  background: var(--bg-card);
}

.page-about .stat-value {
  display: block;
  font-size: clamp(22px, 3.4vw, 30px);
  font-weight: 700;
  color: var(--white);
  letter-spacing: -0.01em;
}

.page-about .stat-value.is-key {
  color: var(--gold);
}

.page-about .stat-label {
  display: block;
  font-size: 12.5px;
  color: var(--text-dim);
  letter-spacing: 0.02em;
}

.page-about .about-hero-figure {
  margin: clamp(26px, 4vw, 42px) 0 0;
}

.page-about .figure-frame {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--ink-100);
  box-shadow: var(--paper);
}

.page-about .figure-frame--glow {
  box-shadow: var(--glow-violet), var(--paper);
}

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

.page-about .figure-cap {
  margin-top: 10px;
  font-size: 12.5px;
  color: var(--text-dim);
  line-height: 1.7;
}

/* ---------- 章节骨架 ---------- */
.page-about .about-body {
  display: grid;
  gap: var(--about-gap);
  margin-top: clamp(36px, 6vw, 72px);
}

.page-about .about-rail {
  position: sticky;
  top: 58px;
  z-index: 4;
  margin-left: calc(var(--gutter) * -1);
  margin-right: calc(var(--gutter) * -1);
  padding: 10px var(--gutter);
  background: rgba(5, 6, 10, 0.86);
  backdrop-filter: blur(10px);
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .rail-title {
  margin: 0 0 8px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--text-dim);
  text-transform: uppercase;
}

.page-about .rail-list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 2px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

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

.page-about .rail-list a {
  display: inline-block;
  white-space: nowrap;
  padding: 7px 13px;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-pill);
  color: var(--text-dim);
  font-size: 13px;
}

.page-about .rail-list a:hover {
  border-color: var(--violet);
  color: var(--white);
}

.page-about .rail-list a[aria-current="true"] {
  color: var(--white);
  border-color: var(--violet);
  background: rgba(139, 92, 246, 0.20);
  box-shadow: var(--glow-violet);
}

.page-about .about-chapter {
  padding-top: clamp(30px, 5vw, 52px);
  border-top: 1px solid var(--line-soft);
}

.page-about .about-chapter h2 {
  margin: 0 0 14px;
  font-size: clamp(23px, 3.6vw, 38px);
  line-height: 1.16;
  font-weight: 900;
  letter-spacing: -0.015em;
  color: var(--white);
}

.page-about .about-chapter h3 {
  margin: 0 0 8px;
  font-size: clamp(17px, 2.3vw, 21px);
  font-weight: 700;
  color: var(--white);
}

.page-about .section-index {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--violet-soft);
}

.page-about .prose p {
  margin: 0 0 16px;
  max-width: 68ch;
  color: var(--text-dim);
  font-size: clamp(15.5px, 1.9vw, 17.5px);
  line-height: 1.9;
}

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

.page-about .about-inline-link {
  margin: 22px 0 0;
  padding: 14px 18px;
  border-left: 3px solid var(--violet);
  background: rgba(139, 92, 246, 0.08);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.8;
}

.page-about .about-band {
  height: 6px;
  border-radius: var(--radius-pill);
  background: linear-gradient(90deg, var(--violet), var(--blue) 48%, var(--pink) 78%, transparent);
  opacity: 0.72;
}

/* ---------- 内容版图 ---------- */
.page-about .about-cats {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-top: 24px;
}

.page-about .about-cat {
  display: grid;
  align-content: start;
  gap: 10px;
  padding: 20px 20px 18px;
  border-radius: var(--radius);
  transition: border-color 0.25s ease, transform 0.25s ease;
}

.page-about .about-cat:hover {
  border-color: var(--blue);
  transform: translateY(-3px);
}

.page-about .about-cat .card-title {
  margin: 0;
  font-size: 19px;
  color: var(--white);
}

.page-about .about-cat .card-text {
  margin: 0;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.85;
}

.page-about .cat-meta {
  margin: 2px 0 0;
  padding-top: 10px;
  border-top: 1px dashed var(--line-soft);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--gold);
}

.page-about .about-map-figure {
  margin: 26px 0 0;
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-top: 20px;
}

.page-about .about-team-figure {
  margin: 0;
}

.page-about .about-split {
  margin-top: 26px;
  padding: 18px;
  background: var(--bg-card);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
}

.page-about .split-bar {
  display: flex;
  height: 14px;
  border-radius: var(--radius-pill);
  overflow: hidden;
  border: 1px solid var(--line-soft);
}

.page-about .split-bar span {
  display: block;
  height: 100%;
}

.page-about .split-ed {
  width: 35.3%;
  background: linear-gradient(90deg, var(--violet-deep), var(--violet));
}

.page-about .split-tech {
  width: 23.5%;
  background: linear-gradient(90deg, var(--blue), rgba(56, 189, 248, 0.6));
}

.page-about .split-ops {
  width: 41.2%;
  background: linear-gradient(90deg, var(--pink), rgba(255, 77, 157, 0.55));
}

.page-about .split-legend {
  display: grid;
  gap: 8px;
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
  font-size: 13.5px;
  color: var(--text-dim);
}

.page-about .split-legend li {
  display: flex;
  align-items: center;
  gap: 8px;
}

.page-about .split-legend .mono {
  color: var(--white);
  font-weight: 700;
}

.page-about .dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  flex: 0 0 auto;
}

.page-about .dot--violet {
  background: var(--violet);
}

.page-about .dot--blue {
  background: var(--blue);
}

.page-about .dot--pink {
  background: var(--pink);
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-timeline li {
  position: relative;
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 16px;
  padding-bottom: 26px;
}

.page-about .about-timeline li::before {
  content: "";
  position: absolute;
  left: 16px;
  top: 38px;
  bottom: 4px;
  width: 1px;
  background: linear-gradient(180deg, var(--violet), rgba(139, 92, 246, 0.06));
}

.page-about .about-timeline li:last-child {
  padding-bottom: 0;
}

.page-about .about-timeline li:last-child::before {
  display: none;
}

.page-about .tl-node {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 1px solid var(--line);
  background: var(--ink-100);
  color: var(--violet-soft);
  font-size: 11.5px;
  transition: border-color 0.25s ease, box-shadow 0.25s ease, color 0.25s ease;
}

.page-about .tl-body {
  padding: 4px 0 0;
}

.page-about .tl-body h3 {
  font-size: clamp(16.5px, 2.2vw, 20px);
}

.page-about .tl-body p {
  margin: 0;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.85;
}

.page-about .about-timeline li:hover .tl-node,
.page-about .about-timeline li:focus-within .tl-node {
  border-color: var(--blue);
  color: var(--white);
  box-shadow: 0 0 0 5px rgba(56, 189, 248, 0.14);
}

.page-about .about-timeline li:hover h3 {
  color: var(--violet-soft);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin-top: 28px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-stats .stat {
  display: grid;
  gap: 4px;
  padding: 16px 18px;
  background: var(--ink-100);
}

/* ---------- 合作 ---------- */
.page-about .about-coop {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 26px 0 24px;
}

.page-about .coop-cell {
  display: grid;
  gap: 6px;
  padding: 16px;
  background: linear-gradient(160deg, rgba(139, 92, 246, 0.14), rgba(15, 18, 25, 0.9));
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.page-about .coop-cell .stat-value {
  font-size: clamp(20px, 3vw, 27px);
}

/* ---------- 联系 ---------- */
.page-about .about-contact {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 24px 0 20px;
}

.page-about .about-facts {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 16px 18px;
  list-style: none;
  border: 1px dashed var(--line-soft);
  border-radius: var(--radius);
  background: rgba(27, 31, 43, 0.42);
  font-size: 12.5px;
  line-height: 1.8;
  color: var(--text-dim);
}

/* ---------- 页尾条 ---------- */
.page-about .about-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-top: clamp(36px, 6vw, 64px);
  padding-top: 22px;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-foot-text {
  margin: 0;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.8;
}

/* ---------- 进入视口动效（JS 未执行时内容完整可读） ---------- */
@keyframes about-rise {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.page-about [data-reveal].is-visible,
.page-about .about-hero [data-reveal].is-visible {
  animation: about-rise 0.5s ease both;
}

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal].is-visible,
  .page-about .about-cat,
  .page-about .tl-node {
    animation: none !important;
    transition: none !important;
    transform: none !important;
  }
}

/* ---------- 平板及以上 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .about-rail {
    margin-left: 0;
    margin-right: 0;
    padding: 10px 0;
    background: transparent;
    backdrop-filter: none;
    border-top: 0;
    border-bottom: 0;
  }

  .page-about .rail-list a {
    font-size: 13.5px;
  }

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

  .page-about .about-facts {
    font-size: 13px;
  }
}

/* ---------- 桌面：左侧时间轴目录 + 宽正文 ---------- */
@media (min-width: 1000px) {
  .page-about .about-rail {
    top: 96px;
    padding: 20px 18px;
    background: var(--bg-card);
    border: 1px solid var(--line-soft);
    border-radius: var(--radius);
    backdrop-filter: none;
  }

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

  .page-about .rail-list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding: 4px 0 0;
  }

  .page-about .rail-list a {
    display: block;
    border: 0;
    border-radius: var(--radius-sm);
    padding: 9px 12px;
    font-size: 14px;
  }

  .page-about .rail-list a[aria-current="true"] {
    background: rgba(139, 92, 246, 0.18);
    box-shadow: inset 3px 0 0 var(--violet);
  }

  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    align-items: start;
    gap: clamp(32px, 5vw, 76px);
  }

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

  .page-about .about-chapter {
    padding-top: clamp(40px, 4vw, 60px);
  }

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

  .page-about .about-team {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.92fr);
    gap: clamp(24px, 3vw, 40px);
    align-items: start;
  }

  .page-about .about-cats {
    gap: 16px;
  }

  .page-about .about-map-figure,
  .page-about .about-team-figure {
    margin-top: 30px;
  }

  .page-about .about-team-figure {
    margin-top: 0;
  }
}

@media (min-width: 1240px) {
  .page-about .about-hero-inner {
    gap: 22px;
  }

  .page-about .about-chapter h2 {
    max-width: 22ch;
  }
}