.page-about {
  --ab-aside-w: 210px;
  background: var(--c-ink);
  color: var(--c-bright);
  font-family: var(--font-sans);
  overflow-x: clip;
}

.page-about .mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.08em;
}

.page-about a:focus-visible,
.page-about [tabindex]:focus-visible {
  outline: 2px solid var(--c-cyan);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  isolation: isolate;
  padding: clamp(24px, 4vw, 40px) 0 clamp(40px, 6vw, 72px);
  background:
    radial-gradient(120% 90% at 88% -12%, rgba(0, 229, 255, 0.16), transparent 62%),
    radial-gradient(90% 70% at 2% 108%, rgba(255, 45, 149, 0.14), transparent 66%),
    var(--c-ink);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  top: 22%;
  left: -12%;
  width: 128%;
  height: 2px;
  background: linear-gradient(90deg, transparent, rgba(0, 229, 255, 0.7), rgba(255, 45, 149, 0.45), transparent);
  transform: rotate(-6deg);
  z-index: -1;
  pointer-events: none;
}

.page-about .ab-hero-inner {
  display: grid;
  gap: clamp(24px, 4vw, 40px);
  min-width: 0;
}

.page-about .ab-hero-main {
  min-width: 0;
}

.page-about .eyebrow {
  color: var(--c-cyan);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  margin: 0 0 18px;
}

.page-about .ab-title {
  margin: 0 0 20px;
  font-size: clamp(34px, 7vw, 72px);
  font-weight: 300;
  line-height: 1.08;
  letter-spacing: -0.01em;
  color: var(--c-bright);
}

.page-about .ab-lede {
  margin: 0;
  max-width: 34em;
  font-size: clamp(15px, 1.7vw, 17px);
  line-height: 1.8;
  color: var(--c-bright);
}

.page-about .ab-hero-aside {
  min-width: 0;
  border-top: 1px solid var(--line);
  padding-top: 18px;
}

.page-about .ab-toc-label {
  margin: 0 0 12px;
  font-size: 12px;
  color: var(--c-silver);
  letter-spacing: 0.16em;
}

.page-about .ab-toc {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .ab-toc a {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 8px 0;
  color: var(--c-silver);
  text-decoration: none;
  font-size: 13px;
  line-height: 1.5;
  border-bottom: 1px solid var(--line);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .ab-toc a .mono {
  color: var(--c-cyan);
  font-size: 11px;
  flex: none;
}

.page-about .ab-toc a:hover {
  color: var(--c-bright);
  border-bottom-color: var(--c-cyan);
}

/* 数字条 */
.page-about .ab-facts {
  list-style: none;
  margin: clamp(28px, 4vw, 44px) 0 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 .ab-fact {
  background: var(--c-ink);
  padding: 16px 14px;
  display: grid;
  gap: 6px;
  min-width: 0;
}

.page-about .ab-fact-num {
  font-size: clamp(24px, 4vw, 32px);
  line-height: 1;
  color: var(--c-cyan);
  font-weight: 500;
}

.page-about .ab-fact-label {
  font-size: 12px;
  color: var(--c-silver);
  letter-spacing: 0.06em;
}

.page-about .ab-hero-figure {
  margin: clamp(24px, 4vw, 40px) 0 0;
}

.page-about .ab-hero-figure img,
.page-about .ab-inline-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border-radius: var(--radius);
  background: var(--c-steel);
}

.page-about .ab-hero-figure img {
  aspect-ratio: 14 / 9;
  border: 1px solid var(--line-strong);
}

.page-about .ab-fig-cap {
  margin: 10px 0 0;
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--c-silver);
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-section {
  padding: clamp(48px, 7vw, 96px) 0;
}

.page-about .ab-section--panel {
  background: var(--c-panel);
}

.page-about .ab-section--steel {
  background: var(--c-steel);
}

.page-about .ab-section--ink {
  background: var(--c-ink);
}

.page-about .ab-section--paper {
  background: var(--c-paper);
  color: var(--c-paper-ink);
}

.page-about .ab-editorial {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  min-width: 0;
}

.page-about .ab-main {
  min-width: 0;
}

.page-about .ab-aside {
  min-width: 0;
  order: -1;
}

.page-about .ab-kicker {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--c-cyan);
}

.page-about .ab-h2 {
  margin: 0 0 clamp(18px, 2.4vw, 26px);
  font-size: clamp(24px, 3.6vw, 40px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--c-bright);
}

.page-about .ab-main p {
  margin: 0 0 16px;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.8;
  max-width: 40em;
}

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

.page-about .ab-aside .ab-seq {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  flex-wrap: wrap;
}

.page-about .ab-seq-num {
  font-size: 26px;
  font-weight: 500;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px var(--c-cyan);
  flex: none;
}

.page-about .ab-seq-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 20px;
  font-size: 12px;
  color: var(--c-silver);
}

.page-about .ab-seq-facts li {
  display: flex;
  gap: 8px;
  align-items: baseline;
}

.page-about .ab-seq-facts .mono {
  color: var(--c-cyan);
  font-size: 12px;
}

/* 三条线 */
.page-about .ab-lines {
  list-style: none;
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
}

.page-about .ab-line {
  background: var(--c-ink);
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 14px;
  padding: 20px 16px;
  align-items: start;
  min-width: 0;
}

.page-about .ab-section--panel .ab-line {
  background: var(--c-panel);
}

.page-about .ab-line-num {
  font-size: 30px;
  line-height: 1;
  color: var(--c-magenta);
  font-weight: 500;
}

.page-about .ab-line-name {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--c-bright);
}

.page-about .ab-line-body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--c-silver);
  max-width: 42em;
}

.page-about .ab-inline-figure {
  margin: clamp(24px, 3.4vw, 36px) 0 0;
}

.page-about .ab-inline-figure img {
  aspect-ratio: 4 / 3;
  border: 1px solid var(--line);
}

/* ---------- 流程 ---------- */
.page-about .ab-flow-head {
  max-width: 44em;
  margin-bottom: clamp(28px, 4vw, 44px);
}

.page-about .ab-flow-lede {
  margin: 0;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.8;
  color: var(--c-bright);
}

.page-about .ab-flow {
  position: relative;
  padding-top: 8px;
}

.page-about .ab-flow-line {
  display: none;
}

.page-about .ab-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
  counter-reset: ab-step;
}

.page-about .ab-step {
  position: relative;
  padding: 0 0 0 22px;
  border-left: 1px solid var(--line-strong);
  min-width: 0;
}

.page-about .ab-step-dot {
  position: absolute;
  left: -4px;
  top: 7px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--c-cyan);
  transition: box-shadow var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .ab-step-time {
  margin: 0 0 6px;
  font-size: 12px;
  color: var(--c-cyan);
  letter-spacing: 0.12em;
}

.page-about .ab-step-name {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--c-bright);
}

.page-about .ab-step-out {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--c-silver);
}

.page-about .ab-step:hover .ab-step-dot,
.page-about .ab-step:focus-within .ab-step-dot {
  background: var(--c-magenta);
  box-shadow: 0 0 0 5px rgba(255, 45, 149, 0.16), 0 0 14px rgba(0, 229, 255, 0.55);
}

.page-about .ab-step:hover .ab-step-out {
  color: var(--c-bright);
}

/* ---------- 纸张章节 ---------- */
.page-about .ab-section--paper .ab-kicker {
  color: #0B6E7E;
}

.page-about .ab-section--paper .ab-h2 {
  color: var(--c-paper-ink);
}

.page-about .ab-section--paper .ab-main p {
  color: var(--c-paper-ink);
}

.page-about .ab-section--paper .ab-fig-cap {
  color: #5A6470;
}

.page-about .ab-section--paper .ab-seq-num {
  -webkit-text-stroke: 1px #0B6E7E;
}

.page-about .ab-section--paper .ab-seq-facts,
.page-about .ab-section--paper .ab-seq-facts .mono {
  color: #3E4A57;
}

.page-about .ab-inline-figure--paper img {
  border: 1px solid rgba(26, 31, 38, 0.16);
  background: #E7E3D9;
}

/* ---------- 专题 ---------- */
.page-about .ab-sub-h3 {
  margin: clamp(26px, 3vw, 36px) 0 10px;
  font-size: clamp(18px, 2.2vw, 22px);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--c-cyan);
}

.page-about .ab-series {
  list-style: none;
  margin: clamp(20px, 2.6vw, 28px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
}

.page-about .ab-series-item {
  background: var(--c-panel);
  padding: 20px 16px;
  min-width: 0;
}

.page-about .ab-series-item .tag {
  display: inline-block;
  margin-bottom: 10px;
}

.page-about .ab-series-name {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 700;
  color: var(--c-bright);
}

.page-about .ab-series-item p {
  margin: 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--c-silver);
  max-width: none;
}

/* ---------- 阶段时间轴 ---------- */
.page-about .ab-stages {
  list-style: none;
  margin: clamp(24px, 3vw, 36px) 0 0;
  padding: 0 0 0 22px;
  position: relative;
}

.page-about .ab-stages::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: linear-gradient(180deg, var(--c-cyan), rgba(0, 229, 255, 0.12));
}

.page-about .ab-stage {
  position: relative;
  padding: 0 0 26px;
  min-width: 0;
}

.page-about .ab-stage:last-child {
  padding-bottom: 0;
}

.page-about .ab-stage::before {
  content: "";
  position: absolute;
  left: -22px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--c-gold);
  box-shadow: 0 0 0 4px rgba(255, 194, 75, 0.14);
}

.page-about .ab-stage-era {
  margin: 0 0 6px;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--c-gold);
}

.page-about .ab-stage h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--c-bright);
}

.page-about .ab-stage p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--c-silver);
  max-width: 40em;
}

.page-about .ab-stage-tail {
  margin-top: clamp(24px, 3vw, 32px) !important;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: 14px !important;
  color: var(--c-silver) !important;
}

/* ---------- CTA ---------- */
.page-about .ab-cta {
  position: relative;
  padding: clamp(48px, 7vw, 88px) 0 clamp(56px, 8vw, 96px);
  background:
    linear-gradient(115deg, rgba(255, 45, 149, 0.16), transparent 46%),
    linear-gradient(295deg, rgba(0, 229, 255, 0.16), transparent 52%),
    var(--c-ink);
  border-top: 1px solid var(--line);
  overflow: hidden;
}

.page-about .ab-cta-inner {
  display: grid;
  gap: 16px;
  max-width: 46em;
}

.page-about .ab-cta-title {
  margin: 0;
  font-size: clamp(26px, 4vw, 44px);
  font-weight: 300;
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--c-bright);
}

.page-about .ab-cta-lede {
  margin: 0;
  font-size: clamp(14px, 1.6vw, 16px);
  line-height: 1.8;
  color: var(--c-silver);
  max-width: 38em;
}

.page-about .ab-inline-link {
  color: var(--c-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 229, 255, 0.45);
}

.page-about .ab-inline-link:hover {
  border-bottom-color: var(--c-cyan);
}

.page-about .ab-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 6px;
}

/* ---------- 动效 ---------- */
.page-about .reveal-armed [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition:
    opacity var(--dur) var(--ease),
    transform var(--dur) var(--ease);
  transition-delay: calc(var(--i, 0) * 80ms);
}

.page-about .reveal-armed [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- 断点 ---------- */
@media (min-width: 600px) {
  .page-about .ab-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .ab-line {
    grid-template-columns: 84px minmax(0, 1fr);
    padding: 24px 20px;
    gap: 20px;
  }

  .page-about .ab-line-num {
    font-size: 38px;
  }

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

@media (min-width: 900px) {
  .page-about .ab-hero-inner {
    grid-template-columns: minmax(0, 1fr) var(--ab-aside-w);
    align-items: start;
    gap: clamp(32px, 5vw, 72px);
  }

  .page-about .ab-hero-aside {
    border-top: 0;
    border-left: 1px solid var(--line);
    padding: 4px 0 0 22px;
    margin-top: 8px;
  }

  .page-about .ab-editorial {
    grid-template-columns: minmax(0, 1fr) var(--ab-aside-w);
    gap: clamp(32px, 5vw, 72px);
    align-items: start;
  }

  .page-about .ab-aside {
    order: 0;
  }

  .page-about .ab-seq {
    position: sticky;
    top: 96px;
    display: block;
  }

  .page-about .ab-seq-num {
    display: block;
    font-size: 44px;
    margin-bottom: 18px;
  }

  .page-about .ab-seq-facts {
    display: grid;
    gap: 10px;
    border-top: 1px solid var(--line);
    padding-top: 14px;
  }

  .page-about .ab-section--paper .ab-seq-facts {
    border-top-color: rgba(26, 31, 38, 0.18);
  }

  /* 流程横向管线 */
  .page-about .ab-flow {
    padding-top: 40px;
  }

  .page-about .ab-flow-line {
    display: block;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
  }

  .page-about .ab-flow-line svg {
    display: block;
    width: 100%;
    height: 4px;
  }

  .page-about .ab-steps {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: clamp(16px, 2.2vw, 28px);
  }

  .page-about .ab-step {
    border-left: 0;
    padding: 0;
  }

  .page-about .ab-step-dot {
    left: 0;
    top: -42px;
    width: 9px;
    height: 9px;
    background: var(--c-ink);
    border: 2px solid var(--c-cyan);
  }

  .page-about .ab-step:last-child .ab-step-dot {
    border-color: var(--c-magenta);
  }
}

@media (min-width: 1200px) {
  .page-about {
    --ab-aside-w: 250px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition: none !important;
    animation: none !important;
  }

  .page-about .reveal-armed [data-reveal] {
    opacity: 1;
    transform: none;
  }
}

.page-about {
  --i: 0.3s;
}