.page-about {
  --about-gap: clamp(18px, 3vw, 34px);
  --about-r: 26px;
  background: var(--c-deep);
  color: var(--c-mist);
  overflow-x: hidden;
}

.page-about .about-hero {
  position: relative;
  padding-top: calc(var(--header-h) + 28px);
  padding-bottom: 12px;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 520px;
  background:
    radial-gradient(60% 70% at 82% 8%, rgba(255, 106, 26, 0.16), transparent 68%),
    radial-gradient(50% 60% at 8% 0%, rgba(31, 169, 160, 0.14), transparent 70%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 16px;
  max-width: 940px;
}

.page-about .about-hero .breadcrumbs {
  margin-bottom: 6px;
}

.page-about .about-hero .breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 13px;
  color: var(--c-grey);
}

.page-about .about-hero .breadcrumb-list li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--c-line);
}

.page-about .about-hero .breadcrumb-list a {
  color: var(--c-grey);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-hero .breadcrumb-list a:hover,
.page-about .about-hero .breadcrumb-list a:focus-visible {
  color: var(--c-orange);
  border-bottom-color: var(--c-orange);
}

.page-about h1 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(30px, 7vw, 56px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--c-mist);
  max-width: 16ch;
}

.page-about .about-lede {
  margin: 0;
  font-size: clamp(15px, 3.6vw, 18px);
  line-height: 1.75;
  color: var(--c-grey);
  max-width: 62ch;
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 8px;
}

.page-about .about-hero-figure {
  position: relative;
  z-index: 1;
  margin: var(--about-gap) 0 0;
  width: min(100% - (var(--gutter) * 2), var(--wrap));
  margin-inline: auto;
}

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

.page-about .media-caption {
  margin-top: 10px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--c-grey);
}

/* ---------- 通用章节 ---------- */

.page-about .about-section {
  padding: 56px 0;
}

.page-about .about-history { padding-top: 44px; }

.page-about .about-head {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.page-about .about-index {
  font-family: var(--font-data);
  font-weight: 700;
  font-size: clamp(30px, 8vw, 52px);
  line-height: 0.9;
  letter-spacing: -0.04em;
  color: var(--c-orange);
  opacity: 0.9;
}

.page-about .about-head-text {
  display: grid;
  gap: 8px;
}

.page-about .about-head-text .h-section {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 5.6vw, 40px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--c-mist);
  max-width: 22ch;
}

.page-about .about-intro {
  margin: 20px 0 0;
  font-size: clamp(15px, 3.4vw, 17px);
  line-height: 1.8;
  color: var(--c-grey);
  max-width: 68ch;
}

/* ---------- 01 时间轴 ---------- */

.page-about .about-timeline {
  list-style: none;
  margin: 34px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .tl-item {
  position: relative;
  padding-left: 34px;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 22px;
  bottom: -16px;
  width: 2px;
  background: linear-gradient(180deg, var(--c-orange), var(--c-line));
  opacity: 0.55;
}

.page-about .tl-item:last-child::before {
  display: none;
}

.page-about .tl-item::after {
  content: "";
  position: absolute;
  left: 1px;
  top: 21px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--c-orange);
  box-shadow: 0 0 0 4px rgba(255, 106, 26, 0.16);
  transition: box-shadow var(--dur) var(--ease);
}

.page-about .tl-item:has(.tl-details[open])::after {
  box-shadow: 0 0 0 7px rgba(255, 106, 26, 0.24);
}

.page-about .tl-details {
  border-radius: var(--r-md);
  background: var(--c-night);
  border: 1px solid var(--c-line);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .tl-details[open] {
  border-color: rgba(255, 106, 26, 0.55);
  background: #142c44;
}

.page-about .tl-summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  min-height: 44px;
  padding: 16px 42px 16px 18px;
  cursor: pointer;
  list-style: none;
  position: relative;
}

.page-about .tl-summary::-webkit-details-marker {
  display: none;
}

.page-about .tl-summary::after {
  content: "";
  position: absolute;
  right: 18px;
  top: 50%;
  width: 9px;
  height: 9px;
  border-right: 2px solid var(--c-orange);
  border-bottom: 2px solid var(--c-orange);
  transform: translateY(-70%) rotate(45deg);
  transition: transform var(--dur) var(--ease);
}

.page-about .tl-details[open] .tl-summary::after {
  transform: translateY(-30%) rotate(-135deg);
}

.page-about .tl-summary:focus-visible {
  outline: 2px solid var(--c-orange);
  outline-offset: 2px;
  border-radius: var(--r-md);
}

.page-about .tl-stage {
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-orange);
}

.page-about .tl-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(16px, 4vw, 19px);
  color: var(--c-mist);
  letter-spacing: -0.01em;
}

.page-about .tl-panel {
  padding: 0 18px 20px;
}

.page-about .tl-panel p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--c-grey);
  max-width: 66ch;
}

/* ---------- 02 分组色带 ---------- */

.page-about .group-band {
  list-style: none;
  margin: 30px 0 0;
  padding: 4px 0 18px;
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(230px, 80%);
  gap: 14px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-about .group-card {
  scroll-snap-align: start;
  position: relative;
  display: grid;
  gap: 8px;
  align-content: start;
  padding: 24px 20px 22px;
  border-radius: var(--r-lg);
  background: var(--c-night);
  border: 1px solid var(--c-line);
  overflow: hidden;
  transition:
    background var(--dur) var(--ease),
    border-color var(--dur) var(--ease),
    transform var(--dur) var(--ease);
}

.page-about .group-card::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--c-orange), transparent 82%);
  opacity: 0.4;
  transition: opacity var(--dur) var(--ease);
}

.page-about .group-card:hover,
.page-about .group-card:focus-within {
  background: #17324c;
  border-color: rgba(255, 106, 26, 0.6);
  transform: translateY(-3px);
}

.page-about .group-card:hover::before,
.page-about .group-card:focus-within::before {
  opacity: 1;
}

.page-about .group-num {
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--c-grey);
}

.page-about .group-name {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--c-mist);
}

.page-about .group-desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--c-grey);
}

.page-about .group-meta {
  margin: 4px 0 0;
  font-size: 12px;
  line-height: 1.6;
  color: var(--c-teal);
  letter-spacing: 0.02em;
  transition: color var(--dur) var(--ease);
}

.page-about .group-card:hover .group-meta {
  color: var(--c-neon);
}

/* ---------- 03 数据链路 ---------- */

.page-about .pipe {
  margin-top: 30px;
  display: grid;
  gap: 14px;
}

.page-about .pipe-step {
  position: relative;
  display: grid;
  gap: 10px;
  align-content: start;
  padding: 26px 22px 24px;
  border-radius: var(--r-lg);
  background:
    linear-gradient(180deg, rgba(31, 169, 160, 0.06), transparent 55%),
    var(--c-night);
  border: 1px solid var(--c-line);
}

.page-about .pipe-step::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 44px;
  height: 3px;
  border-radius: 0 3px 0 0;
  background: var(--c-line);
}

.page-about .pipe-step--a::after { background: var(--c-orange); }
.page-about .pipe-step--b::after { background: var(--c-orange-soft); }
.page-about .pipe-step--c::after { background: var(--c-teal); }

.page-about .pipe-tag {
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--c-grey);
}

.page-about .pipe-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 22px;
  letter-spacing: -0.01em;
  color: var(--c-mist);
}

.page-about .pipe-body {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--c-grey);
}

.page-about .pipe-note {
  margin: 26px 0 0;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 10px;
  padding: 20px 22px;
  border-radius: var(--r-md);
  border: 1px dashed var(--c-line);
  background: rgba(18, 41, 63, 0.6);
}

.page-about .pipe-note-num {
  font-family: var(--font-data);
  font-weight: 700;
  font-size: clamp(38px, 10vw, 64px);
  line-height: 1;
  letter-spacing: -0.04em;
  color: var(--c-neon);
  font-variant-numeric: tabular-nums;
}

.page-about .pipe-note-unit {
  font-family: var(--font-data);
  font-size: 16px;
  color: var(--c-neon);
}

.page-about .pipe-note-text {
  font-size: 14px;
  line-height: 1.7;
  color: var(--c-grey);
  flex: 1 1 220px;
}

/* ---------- 04 版本标签页 ---------- */

.page-about .about-tabs {
  margin-top: 30px;
}

.page-about .about-tabs .tab-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 18px;
  padding: 0;
}

.page-about .about-tabs .tab {
  min-height: 44px;
  padding: 10px 24px;
  border-radius: var(--r-pill);
  border: 1px solid var(--c-line);
  background: transparent;
  color: var(--c-grey);
  font-family: var(--font-data);
  font-size: 15px;
  letter-spacing: 0.08em;
  cursor: pointer;
  transition:
    background var(--dur-fast) var(--ease),
    border-color var(--dur-fast) var(--ease),
    color var(--dur-fast) var(--ease);
}

.page-about .about-tabs .tab:hover {
  border-color: var(--c-orange-soft);
  color: var(--c-mist);
}

.page-about .about-tabs .tab:focus-visible {
  outline: 2px solid var(--c-orange);
  outline-offset: 2px;
}

.page-about .about-tabs .tab[aria-selected="true"] {
  background: var(--c-orange);
  border-color: var(--c-orange);
  color: var(--c-ink);
  font-weight: 700;
}

.page-about .about-panel {
  padding: 26px 22px 28px;
  border-radius: var(--r-lg);
  background: var(--c-night);
  border: 1px solid var(--c-line);
  border-left: 3px solid var(--c-orange);
}

.page-about .about-panel[hidden] {
  display: none;
}

.page-about .panel-title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(19px, 4.6vw, 24px);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--c-mist);
}

.page-about .panel-lead {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--c-orange-soft);
  max-width: 60ch;
}

.page-about .panel-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .panel-list li {
  position: relative;
  padding-left: 20px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--c-grey);
}

.page-about .panel-list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 11px;
  width: 7px;
  height: 7px;
  border-radius: 2px;
  background: var(--c-teal);
}

.page-about .about-versions-figure {
  margin: 40px auto 0;
  width: min(100% - (var(--gutter) * 2), var(--wrap));
}

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

/* ---------- 05 团队 ---------- */

.page-about .about-team-grid {
  display: grid;
  gap: 34px;
}

.page-about .team-list {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  gap: 20px;
}

.page-about .team-row {
  display: grid;
  gap: 8px;
  padding-left: 18px;
  border-left: 2px solid var(--c-line);
  transition: border-color var(--dur) var(--ease);
}

.page-about .team-row:nth-child(1) { border-left-color: var(--c-orange); }
.page-about .team-row:nth-child(2) { border-left-color: var(--c-teal); }
.page-about .team-row:nth-child(3) { border-left-color: var(--c-orange-soft); }

.page-about .team-row:hover {
  border-left-color: var(--c-neon);
}

.page-about .team-role {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -0.01em;
  color: var(--c-mist);
}

.page-about .team-desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--c-grey);
  max-width: 58ch;
}

.page-about .team-place {
  margin: 24px 0 0;
  padding: 16px 18px;
  border-radius: var(--r-md);
  background: rgba(31, 169, 160, 0.09);
  border: 1px solid rgba(31, 169, 160, 0.32);
  font-size: 14px;
  line-height: 1.75;
  color: var(--c-mist);
  max-width: 58ch;
}

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

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

/* ---------- 06 覆盖范围 ---------- */

.page-about .reach-grid {
  margin-top: 30px;
  display: grid;
  gap: 14px;
}

.page-about .reach-cell {
  display: grid;
  gap: 8px;
  align-content: start;
  padding: 24px 20px;
  border-radius: var(--r-lg);
  background: var(--c-night);
  border: 1px solid var(--c-line);
}

.page-about .reach-cell--lead {
  background:
    linear-gradient(135deg, rgba(255, 106, 26, 0.16), transparent 62%),
    var(--c-night);
  border-color: rgba(255, 106, 26, 0.45);
}

.page-about .reach-num {
  font-family: var(--font-data);
  font-weight: 700;
  font-size: clamp(34px, 9vw, 52px);
  line-height: 1;
  letter-spacing: -0.04em;
  color: var(--c-mist);
  font-variant-numeric: tabular-nums;
}

.page-about .reach-cell--lead .reach-num {
  color: var(--c-orange);
}

.page-about .reach-label {
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--c-grey);
}

/* ---------- 收尾导航 ---------- */

.page-about .about-next {
  padding: 56px 0 72px;
  border-top: 1px solid var(--c-line);
  background:
    radial-gradient(70% 90% at 50% 0%, rgba(31, 169, 160, 0.12), transparent 70%),
    var(--c-ink);
}

.page-about .about-next-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 5.4vw, 36px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--c-mist);
}

.page-about .about-next-lead {
  margin: 14px 0 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--c-grey);
  max-width: 58ch;
}

.page-about .about-next-list {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .next-item a {
  display: grid;
  gap: 6px;
  min-height: 44px;
  padding: 20px 22px;
  border-radius: var(--r-md);
  border: 1px solid var(--c-line);
  background: rgba(18, 41, 63, 0.6);
  text-decoration: none;
  transition:
    border-color var(--dur) var(--ease),
    background var(--dur) var(--ease),
    transform var(--dur) var(--ease);
}

.page-about .next-item a:hover,
.page-about .next-item a:focus-visible {
  border-color: var(--c-orange);
  background: #17324c;
  transform: translateY(-2px);
}

.page-about .next-item a:focus-visible {
  outline: 2px solid var(--c-orange);
  outline-offset: 3px;
}

.page-about .next-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  color: var(--c-mist);
}

.page-about .next-desc {
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--c-grey);
}

.page-about .next-item a:hover .next-title {
  color: var(--c-orange);
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-hero {
    padding-top: calc(var(--header-h) + 48px);
  }

  .page-about .about-section {
    padding: 72px 0;
  }

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

  .page-about .reach-cell--lead {
    grid-column: span 2;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero {
    padding-top: calc(var(--header-h) + 64px);
  }

  .page-about .about-head {
    flex-direction: row;
    align-items: flex-start;
    gap: 26px;
  }

  .page-about .about-head .about-index {
    flex: 0 0 auto;
    min-width: 84px;
  }

  .page-about .about-intro {
    margin-left: 110px;
  }

  .page-about .about-timeline {
    margin-left: 110px;
  }

  .page-about .about-section {
    padding: 92px 0;
  }

  .page-about .group-band {
    grid-auto-flow: row;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    grid-auto-columns: auto;
    overflow-x: visible;
    scroll-snap-type: none;
    padding-bottom: 4px;
  }

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

  .page-about .about-team-grid {
    grid-template-columns: 1.15fr 0.85fr;
    align-items: start;
    gap: 44px;
  }

  .page-about .about-team-grid .about-intro,
  .page-about .about-team-grid .team-list,
  .page-about .about-team-grid .team-place {
    margin-left: 0;
  }

  .page-about .about-team-grid .about-head {
    flex-direction: column;
    gap: 10px;
  }

  .page-about .about-team-grid .about-index {
    min-width: 0;
  }

  .page-about .about-team-figure {
    position: sticky;
    top: calc(var(--header-h) + 24px);
  }

  .page-about .reach-grid {
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
  }

  .page-about .reach-cell--lead {
    grid-column: auto;
  }

  .page-about .about-next-list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-next-lead {
    margin-left: 0;
  }
}

@media (min-width: 1180px) {
  .page-about .about-hero-figure,
  .page-about .about-versions-figure {
    width: var(--wrap);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .group-card,
  .page-about .next-item a,
  .page-about .tl-item::after,
  .page-about .tl-summary::after {
    transition: none !important;
    transform: none !important;
  }

  .page-about .group-card:hover,
  .page-about .next-item a:hover {
    transform: none !important;
  }
}