.page-about {
  --about-line: rgba(27, 39, 64, .9);
  --about-dimline: rgba(27, 39, 64, .5);
  --about-sink: rgba(255, 106, 26, .16);
  position: relative;
  padding-bottom: 88px;
}

/* ---------- 面包屑与首屏 ---------- */
.page-about .breadcrumbs {
  padding: 22px 0 0;
}

.page-about .about-hero {
  position: relative;
  padding: 18px 0 62px;
  isolation: isolate;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--about-dimline) 1px, transparent 1px),
    linear-gradient(to bottom, var(--about-dimline) 1px, transparent 1px);
  background-size: 24px 24px;
  -webkit-mask-image: radial-gradient(120% 90% at 22% 12%, #000 0%, rgba(0, 0, 0, .35) 48%, transparent 82%);
  mask-image: radial-gradient(120% 90% at 22% 12%, #000 0%, rgba(0, 0, 0, .35) 48%, transparent 82%);
  pointer-events: none;
  z-index: -1;
}

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
  align-items: start;
}

.page-about .hero-copy .eyebrow {
  margin: 0 0 14px;
}

.page-about .hero-copy h1 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.1rem, 7vw, 3.5rem);
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--text);
}

.page-about .hero-copy h1 .hl {
  color: var(--orange);
  position: relative;
}

.page-about .hero-copy h1 .hl::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -6px;
  height: 3px;
  background: linear-gradient(90deg, var(--orange), var(--purple));
  border-radius: 2px;
}

.page-about .hero-lead {
  margin: 22px 0 0;
  max-width: 40ch;
  font-size: 1rem;
  line-height: 1.75;
  color: var(--dim);
}

.page-about .hero-points {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  margin: 22px 0 0;
}

.page-about .hero-point {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: .8125rem;
  letter-spacing: .01em;
  color: var(--text);
  padding: 7px 13px;
  border: 1px solid var(--grid);
  border-radius: var(--radius-pill);
  background: rgba(15, 23, 40, .72);
}

.page-about .dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  flex: none;
}

.page-about .dot--teal { background: var(--teal); box-shadow: 0 0 8px rgba(43, 227, 198, .7); }
.page-about .dot--orange { background: var(--orange); box-shadow: 0 0 8px rgba(255, 106, 26, .7); }
.page-about .dot--purple { background: var(--purple); box-shadow: 0 0 8px rgba(162, 75, 255, .7); }

.page-about .hero-copy .btn-row {
  margin-top: 26px;
}

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

.page-about .hero-figure .media-frame {
  border: 2px solid var(--grid);
  box-shadow: var(--shadow-hard);
  position: relative;
  overflow: hidden;
}

.page-about .hero-figure .media-frame::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 46px;
  height: 46px;
  background: var(--orange);
  clip-path: polygon(0 0, 100% 0, 0 100%);
  z-index: 2;
}

.page-about .hero-figure .media-frame img,
.page-about .pipeline-figure .media-frame img,
.page-about .version-figure .media-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 目录 / 主体两栏 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
}

.page-about .about-index {
  border-left: 2px solid var(--grid);
  padding-left: 16px;
}

.page-about .about-index .side-index-title {
  font-family: var(--font-mono);
  font-size: .75rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--dim);
  margin: 0 0 12px;
}

.page-about .about-index .index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.page-about .about-index .index-link {
  display: inline-block;
  font-size: .875rem;
  color: var(--dim);
  text-decoration: none;
  padding: 4px 0;
  border-bottom: 1px solid transparent;
  transition: color .16s ease, border-color .16s ease;
}

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

.page-about .about-index .index-link[aria-current="true"],
.page-about .about-index .index-link[aria-current="page"] {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

/* ---------- 章节通用 ---------- */
.page-about .about-body {
  display: flex;
  flex-direction: column;
  gap: 66px;
  min-width: 0;
}

.page-about .about-stage {
  scroll-margin-top: 96px;
  min-width: 0;
}

.page-about .stage-head {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  align-items: start;
  padding-bottom: 16px;
  border-bottom: 2px solid var(--grid);
  margin-bottom: 26px;
}

.page-about .stage-code {
  font-family: var(--font-mono);
  font-size: .8125rem;
  font-weight: 600;
  color: var(--orange);
  border: 1px solid rgba(255, 106, 26, .45);
  border-radius: var(--radius-xs);
  padding: 3px 7px;
  line-height: 1.4;
}

.page-about .stage-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.5rem, 4vw, 2.1rem);
  letter-spacing: -0.015em;
  color: var(--text);
}

.page-about .stage-lead {
  margin: 8px 0 0;
  font-size: .9375rem;
  line-height: 1.7;
  color: var(--dim);
  max-width: 42ch;
}

/* ---------- 01 角色卡 ---------- */
.page-about .role-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .role-card {
  position: relative;
  background: var(--panel);
  border: 2px solid var(--grid);
  border-radius: var(--radius-md);
  padding: 22px 20px 20px;
  box-shadow: var(--shadow-hard);
  transition: border-color .16s ease, transform .16s ease;
}

.page-about .role-card::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 34px;
  height: 34px;
  background: linear-gradient(225deg, rgba(162, 75, 255, .55), transparent 70%);
  clip-path: polygon(100% 0, 100% 100%, 0 0);
}

.page-about .role-card:hover {
  border-color: var(--orange);
  transform: translateY(-3px);
}

.page-about .role-title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.125rem;
  letter-spacing: -0.01em;
  color: var(--orange);
}

.page-about .role-text {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--dim);
}

.page-about .about-stats {
  margin-top: 22px;
  border-top: 1px solid var(--about-line);
  padding-top: 20px;
}

.page-about .about-stats .stat-value {
  font-family: var(--font-mono);
}

.page-about .about-stats .stat-label {
  line-height: 1.6;
}

/* ---------- 02 体量 ---------- */
.page-about .coverage-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

.page-about .coverage-scale {
  background: var(--panel);
  border: 2px solid var(--grid);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--shadow-hard);
}

.page-about .scale-bar {
  position: relative;
  height: 10px;
  border-radius: var(--radius-pill);
  background: var(--grid);
  overflow: hidden;
}

.page-about .scale-fill {
  display: block;
  height: 100%;
  width: 100%;
  background: linear-gradient(90deg, var(--orange), var(--purple) 62%, var(--teal));
  border-radius: var(--radius-pill);
}

.page-about .scale-legend {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .scale-legend li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-size: .875rem;
  color: var(--dim);
  border-bottom: 1px dashed var(--about-dimline);
  padding-bottom: 10px;
}

.page-about .scale-legend li:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .scale-num {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 1.125rem;
  color: var(--text);
  min-width: 4.5ch;
}

.page-about .coverage-copy p {
  margin: 0 0 16px;
  font-size: .9375rem;
  line-height: 1.8;
  color: var(--dim);
  max-width: 42ch;
}

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

.page-about .coverage-foot {
  color: var(--text);
}

.page-about .coverage-copy a,
.page-about .pipeline-note a,
.page-about .legacy-more a,
.page-about .partner-text a {
  color: var(--info);
  text-decoration: none;
  border-bottom: 1px solid rgba(58, 141, 255, .45);
}

.page-about .coverage-copy a:hover,
.page-about .pipeline-note a:hover,
.page-about .legacy-more a:hover,
.page-about .partner-text a:hover {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

/* ---------- 03 链路 ---------- */
.page-about .pipeline-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  align-items: start;
}

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

.page-about .pipeline-figure .media-frame {
  border: 2px solid var(--grid);
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: var(--shadow-hard);
}

.page-about .pipeline-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: none;
}

.page-about .pipe-step {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .pipe-step:first-child {
  padding-top: 0;
}

.page-about .pipe-step:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .pipe-code {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: .875rem;
  color: var(--teal);
  width: 30px;
  height: 30px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(43, 227, 198, .4);
  border-radius: var(--radius-xs);
  flex: none;
}

.page-about .pipe-title {
  margin: 4px 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: -0.005em;
  color: var(--text);
}

.page-about .pipe-body p {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--dim);
}

.page-about .pipeline-note {
  margin-top: 24px;
  padding: 16px 18px;
  border-left: 3px solid var(--purple);
  background: rgba(162, 75, 255, .08);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.page-about .pipeline-note p {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.75;
  color: var(--text);
}

/* ---------- 04 版本时间轴 ---------- */
.page-about .version-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
  align-items: start;
}

.page-about .timeline {
  position: relative;
  margin: 0;
  padding: 2px 0 2px 30px;
  border-left: 2px solid var(--grid);
}

.page-about .tl-node {
  position: relative;
  border-bottom: 1px solid var(--about-line);
}

.page-about .tl-node:last-child {
  border-bottom: 0;
}

.page-about .tl-node::before {
  content: "";
  position: absolute;
  left: -39px;
  top: 20px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--grid);
  transition: border-color .16s ease, background .16s ease, box-shadow .16s ease;
}

.page-about .tl-node[open]::before,
.page-about .tl-node.is-current::before {
  border-color: var(--orange);
  background: var(--orange);
  box-shadow: 0 0 0 4px var(--about-sink);
}

.page-about .tl-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 6px 16px 0;
  cursor: pointer;
  list-style: none;
  transition: color .16s ease;
}

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

.page-about .tl-head::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--purple);
}

.page-about .tl-node[open] .tl-head::after {
  content: "–";
  color: var(--orange);
}

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

.page-about .tl-head:focus-visible {
  outline: 2px solid var(--purple);
  outline-offset: 2px;
}

.page-about .tl-ver {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 1rem;
  color: var(--orange);
  min-width: 3.2ch;
}

.page-about .tl-node.is-current .tl-ver {
  color: var(--teal);
}

.page-about .tl-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: -0.005em;
  color: var(--text);
  transition: color .16s ease;
}

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

.page-about .tl-body p {
  margin: 0;
  font-size: .9375rem;
  line-height: 1.78;
  color: var(--dim);
  max-width: 44ch;
}

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

.page-about .version-figure .media-frame {
  border: 2px solid var(--grid);
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: var(--shadow-hard);
}

.page-about .device-line {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 12px;
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--about-line);
}

.page-about .device-chip {
  font-family: var(--font-mono);
  font-size: .78rem;
  color: var(--text);
  border: 1px solid var(--grid);
  border-radius: var(--radius-pill);
  padding: 6px 12px;
  background: var(--panel);
}

.page-about .device-link {
  font-family: var(--font-mono);
  font-size: .8125rem;
  color: var(--info);
  text-decoration: none;
  margin-left: auto;
  border-bottom: 1px solid rgba(58, 141, 255, .4);
}

.page-about .device-link:hover {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

/* ---------- 05 旧版专区 ---------- */
.page-about .legacy-panel {
  background: linear-gradient(180deg, rgba(15, 23, 40, .95), rgba(7, 11, 20, .95));
  border: 2px solid var(--grid);
  border-radius: var(--radius-md);
  padding: 24px 20px;
  box-shadow: var(--shadow-hard);
  position: relative;
  overflow: hidden;
}

.page-about .legacy-panel::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(135deg, rgba(27, 39, 64, .55) 0 1px, transparent 1px 12px);
  opacity: .5;
  pointer-events: none;
}

.page-about .legacy-lead {
  position: relative;
  margin: 0 0 20px;
  font-size: .9375rem;
  line-height: 1.8;
  color: var(--text);
  max-width: 44ch;
}

.page-about .legacy-list {
  position: relative;
  list-style: none;
  margin: 0 0 20px;
  padding: 0;
}

.page-about .legacy-list li {
  display: grid;
  grid-template-columns: 3.4rem 1fr;
  gap: 14px;
  align-items: center;
  padding: 11px 0;
  border-bottom: 1px solid var(--about-dimline);
  transition: background .16s ease;
}

.page-about .legacy-list li:last-child {
  border-bottom: 0;
}

.page-about .legacy-list li:hover {
  background: rgba(255, 106, 26, .07);
}

.page-about .legacy-ver {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: .9rem;
  color: var(--purple);
}

.page-about .legacy-desc {
  font-size: .9rem;
  line-height: 1.6;
  color: var(--dim);
}

.page-about .legacy-more {
  position: relative;
  margin: 0;
  font-size: .9rem;
  line-height: 1.75;
  color: var(--dim);
  padding-top: 4px;
}

/* ---------- 06 团队与合作 ---------- */
.page-about .team-list {
  list-style: none;
  margin: 0 0 28px;
  padding: 0;
  border-top: 1px solid var(--about-line);
}

.page-about .team-item {
  display: grid;
  grid-template-columns: 2.6rem 6rem 1fr;
  gap: 8px 14px;
  align-items: baseline;
  padding: 15px 0;
  border-bottom: 1px solid var(--about-line);
  transition: background .16s ease, border-color .16s ease;
}

.page-about .team-item:hover {
  background: rgba(43, 227, 198, .05);
  border-bottom-color: var(--teal);
}

.page-about .team-code {
  font-family: var(--font-mono);
  font-size: .8125rem;
  font-weight: 600;
  color: var(--teal);
}

.page-about .team-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.0625rem;
  color: var(--text);
}

.page-about .team-desc {
  font-size: .9rem;
  line-height: 1.7;
  color: var(--dim);
}

.page-about .partner-block {
  border-left: 3px solid var(--purple);
  padding: 4px 0 4px 18px;
}

.page-about .partner-title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--purple);
  letter-spacing: -0.005em;
}

.page-about .partner-text {
  margin: 0 0 12px;
  font-size: .9375rem;
  line-height: 1.78;
  color: var(--dim);
  max-width: 44ch;
}

.page-about .partner-text:last-child {
  margin-bottom: 0;
}

.page-about .about-cta {
  margin-top: 34px;
  padding: 26px 22px;
  border: 2px solid var(--orange);
  border-radius: var(--radius-md);
  background: linear-gradient(120deg, rgba(255, 106, 26, .12), rgba(162, 75, 255, .1));
  box-shadow: var(--shadow-hard);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px;
}

.page-about .cta-line {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.25rem, 3.4vw, 1.65rem);
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .about-cta .btn-row {
  margin-left: auto;
}

/* ---------- 桌面端 ---------- */
@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
    gap: 46px;
    align-items: end;
  }

  .page-about .hero-copy {
    padding-bottom: 12px;
  }

  .page-about .hero-figure {
    margin-top: -18px;
    transform: translateX(10px);
  }

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

  .page-about .coverage-grid {
    grid-template-columns: minmax(0, .85fr) minmax(0, 1.15fr);
    gap: 38px;
    align-items: start;
  }

  .page-about .pipeline-grid {
    grid-template-columns: minmax(0, .95fr) minmax(0, 1.05fr);
    gap: 34px;
  }

  .page-about .version-grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    gap: 36px;
  }

  .page-about .version-figure {
    margin-top: 26px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-layout {
    grid-template-columns: 208px minmax(0, 1fr);
    gap: 52px;
  }

  .page-about .about-index {
    position: sticky;
    top: 98px;
    align-self: start;
    border-left: 2px solid var(--grid);
  }

  .page-about .about-index .index-list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 2px;
  }

  .page-about .about-index .index-link {
    display: block;
    padding: 7px 0;
    font-size: .875rem;
  }
}

@media (min-width: 1200px) {
  .page-about .about-body {
    gap: 78px;
  }
}

/* ---------- 窄屏收敛 ---------- */
@media (max-width: 640px) {
  .page-about .about-hero {
    padding-bottom: 44px;
  }

  .page-about .hero-point {
    font-size: .75rem;
    padding: 6px 11px;
  }

  .page-about .about-body {
    gap: 52px;
  }

  .page-about .team-item {
    grid-template-columns: 2.2rem 1fr;
  }

  .page-about .team-desc {
    grid-column: 2 / -1;
  }

  .page-about .about-cta {
    padding: 22px 18px;
  }

  .page-about .about-cta .btn-row {
    margin-left: 0;
    width: 100%;
  }

  .page-about .device-link {
    margin-left: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .role-card,
  .page-about .tl-node::before,
  .page-about .tl-name,
  .page-about .about-index .index-link,
  .page-about .legacy-list li,
  .page-about .team-item {
    transition: none;
  }

  .page-about .role-card:hover {
    transform: none;
  }

  .page-about .hero-figure {
    transform: none;
  }
}