.page-about {
  --pa-rail: 2.25rem;
  --pa-line-soft: rgba(154, 107, 255, 0.24);
  display: block;
  position: relative;
  padding-bottom: clamp(2rem, 6vw, 4rem);
  background:
    radial-gradient(58% 38% at 90% 4%, rgba(108, 63, 197, 0.26), transparent 72%),
    radial-gradient(46% 30% at 4% 58%, rgba(0, 229, 255, 0.09), transparent 74%);
}

.page-about .about-crumb {
  padding-top: clamp(1rem, 3vw, 1.75rem);
}

/* ---------- 首屏：分屏叙事 + 轨道刻度 ---------- */
.page-about .about-hero {
  padding-top: clamp(1.25rem, 4vw, 3rem);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(1.75rem, 5vw, 3.5rem);
  align-items: center;
}

.page-about .about-hero__lead h1 {
  margin: 0.85rem 0 0;
  font-size: clamp(1.9rem, 5.4vw, 3.4rem);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--c-ink-bright);
}

.page-about .about-hero__lede {
  margin: 1.15rem 0 0;
  max-width: 40ch;
  font-size: var(--fs-17);
  line-height: 1.85;
  letter-spacing: 0.02em;
  color: var(--c-ink-dim);
}

.page-about .about-hero__orbit {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 220px;
}

.page-about .about-orbit {
  width: min(100%, 360px);
  height: auto;
  display: block;
  animation: pa-orbit-drift 26s linear infinite;
}

.page-about .about-orbit__caption {
  position: absolute;
  bottom: 0.25rem;
  right: 0.5rem;
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--c-galaxy-2);
}

@keyframes pa-orbit-drift {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.page-about .about-hero__stats {
  list-style: none;
  margin: clamp(1.75rem, 4vw, 2.75rem) 0 0;
  padding: clamp(1rem, 3vw, 1.5rem) 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem 1.25rem;
  border-top: 1px solid var(--c-rule);
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  min-width: 0;
}

.page-about .about-stat__num {
  font-size: var(--fs-28);
  line-height: 1.1;
  letter-spacing: 0.04em;
  color: var(--c-pulse);
}

.page-about .about-stat__label {
  font-size: var(--fs-13);
  letter-spacing: 0.06em;
  color: var(--c-ink-dim);
}

/* ---------- 通用分屏与章节头 ---------- */
.page-about .about-split {
  display: grid;
  gap: clamp(1.25rem, 4vw, 2.5rem);
}

.page-about .about-split__aside h2 {
  margin: 0.7rem 0 0;
  font-size: clamp(1.4rem, 3.4vw, 2rem);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--c-ink-bright);
}

.page-about .about-split__note {
  margin: 1rem 0 0;
  font-size: var(--fs-13);
  line-height: 1.8;
  color: var(--c-ink-dim);
  border-left: 2px solid var(--pa-line-soft);
  padding-left: 0.85rem;
}

.page-about .about-split__body p {
  margin: 0 0 1.1rem;
}

.page-about .about-section-head {
  max-width: 62ch;
  margin-bottom: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-section-head h2 {
  margin: 0.7rem 0 0;
  font-size: clamp(1.4rem, 3.6vw, 2.1rem);
  line-height: 1.28;
  letter-spacing: -0.01em;
  color: var(--c-ink-bright);
}

.page-about .about-section-head__note {
  margin: 0.85rem 0 0;
  font-size: var(--fs-15);
  line-height: 1.85;
  color: var(--c-ink-dim);
}

/* ---------- 时间线 ---------- */
.page-about .about-figure {
  margin: 0 0 clamp(2rem, 5vw, 3rem);
}

.page-about .about-timeline {
  position: relative;
  display: grid;
  gap: 0;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: calc(var(--pa-rail) / 2 - 0.5px);
  top: 1.5rem;
  bottom: 1.5rem;
  width: 1px;
  background: repeating-linear-gradient(
    to bottom,
    var(--c-rule) 0 6px,
    transparent 6px 15px
  );
}

.page-about .about-stage {
  display: grid;
  grid-template-columns: var(--pa-rail) minmax(0, 1fr);
  padding: 0.75rem 0 1.5rem;
}

.page-about .about-stage__node {
  display: flex;
  justify-content: center;
  padding-top: 1.15rem;
}

.page-about .about-stage__node::before {
  content: "";
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--c-night);
  border: 1px solid var(--c-galaxy);
  box-shadow: 0 0 0 4px rgba(108, 63, 197, 0.14);
  transition: background 240ms ease, border-color 240ms ease, box-shadow 240ms ease;
}

.page-about .about-stage[data-open="true"] .about-stage__node::before {
  background: var(--c-pulse);
  border-color: var(--c-pulse);
  box-shadow: 0 0 0 4px rgba(0, 229, 255, 0.16), var(--glow-pulse);
}

.page-about .about-stage__main {
  min-width: 0;
  padding-left: clamp(0.6rem, 2vw, 1.25rem);
}

.page-about .about-stage__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.4rem 0.9rem;
  width: 100%;
  margin: 0;
  padding: 0.35rem 0 0.7rem;
  background: none;
  border: 0;
  border-bottom: 1px solid var(--c-rule);
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: border-color 240ms ease;
}

.page-about .about-stage__head:hover,
.page-about .about-stage__head:focus-visible {
  border-bottom-color: var(--c-pulse);
}

.page-about .about-stage__head:focus-visible {
  outline: 2px solid var(--c-pulse);
  outline-offset: 2px;
}

.page-about .about-stage__no {
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--c-galaxy-2);
}

.page-about .about-stage__name {
  font-size: var(--fs-21);
  font-weight: 700;
  letter-spacing: -0.005em;
  color: var(--c-ink-bright);
}

.page-about .about-stage__count {
  font-size: var(--fs-15);
  letter-spacing: 0.06em;
  color: var(--c-pulse);
}

.page-about .about-stage__mark {
  position: relative;
  margin-left: auto;
  align-self: center;
  width: 14px;
  height: 14px;
  flex: none;
}

.page-about .about-stage__mark::before,
.page-about .about-stage__mark::after {
  content: "";
  position: absolute;
  background: var(--c-galaxy-2);
  border-radius: 1px;
}

.page-about .about-stage__mark::before {
  left: 50%;
  top: 0;
  width: 1px;
  height: 100%;
  transform: translateX(-0.5px);
  transition: transform 240ms ease;
}

.page-about .about-stage__mark::after {
  top: 50%;
  left: 0;
  height: 1px;
  width: 100%;
  transform: translateY(-0.5px);
}

.page-about .about-stage[data-open="true"] .about-stage__mark::before {
  transform: translateX(-0.5px) scaleY(0);
}

.page-about .about-stage__desc {
  margin: 0.9rem 0 0;
  max-width: 52ch;
  font-size: var(--fs-15);
  line-height: 1.85;
  letter-spacing: 0.02em;
  color: var(--c-ink);
}

.page-about .about-stage__bar {
  margin-top: 0.95rem;
  height: 4px;
  border-radius: 2px;
  background: rgba(42, 58, 102, 0.55);
  overflow: hidden;
}

.page-about .about-stage__bar span {
  display: block;
  height: 100%;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--c-galaxy), var(--c-pulse));
  transition: width 400ms ease;
}

.page-about .about-stage:nth-of-type(1) .about-stage__bar span { width: 8%; }
.page-about .about-stage:nth-of-type(2) .about-stage__bar span { width: 35%; }
.page-about .about-stage:nth-of-type(3) .about-stage__bar span { width: 66%; }
.page-about .about-stage:nth-of-type(4) .about-stage__bar span { width: 91%; }
.page-about .about-stage:nth-of-type(5) .about-stage__bar span { width: 100%; }

.page-about .about-stage__body {
  overflow: hidden;
}

.page-about .about-stage[data-open="false"] .about-stage__body {
  display: none;
}

.page-about .about-stage__inner {
  margin-top: 1rem;
  padding: 1rem 0 0 1rem;
  border-left: 1px solid var(--pa-line-soft);
  animation: pa-fade-in 200ms ease both;
}

@keyframes pa-fade-in {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}

.page-about .about-stage__inner > p {
  margin: 0 0 0.7rem;
  font-size: var(--fs-15);
  line-height: 1.85;
  color: var(--c-ink-dim);
}

.page-about .about-stage__list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.5rem;
}

.page-about .about-stage__list li {
  position: relative;
  padding-left: 1.1rem;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--c-ink);
}

.page-about .about-stage__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  border: 1px solid var(--c-galaxy-2);
}

.page-about .about-note {
  margin: 0 0 1.75rem var(--pa-rail);
  padding: 1.15rem 1.3rem;
  border-left: 2px solid rgba(0, 229, 255, 0.55);
  border-radius: 0 var(--r-m) var(--r-m) 0;
  background: linear-gradient(120deg, rgba(20, 42, 92, 0.9), rgba(16, 31, 68, 0.55));
}

.page-about .about-note__label {
  margin: 0 0 0.5rem;
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--c-pulse);
}

.page-about .about-note p:last-child {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.85;
  color: var(--c-ink-dim);
}

/* ---------- 九人小组 ---------- */
.page-about .about-team__grid {
  display: grid;
  gap: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-team__intro h2 {
  margin: 0.7rem 0 0.9rem;
  font-size: clamp(1.4rem, 3.6vw, 2.1rem);
  line-height: 1.28;
  color: var(--c-ink-bright);
}

.page-about .about-team__intro .prose p {
  margin: 0;
}

.page-about .about-team__figure {
  margin: 0;
}

.page-about .about-team__roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.page-about .about-role {
  padding: 1.25rem 1.35rem;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  transition: border-color 240ms ease, transform 240ms ease;
}

.page-about .about-role:hover {
  border-color: var(--c-galaxy-2);
  transform: translateY(-2px);
}

.page-about .about-role__no {
  margin: 0;
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--c-galaxy-2);
}

.page-about .about-role__title {
  margin: 0;
  font-size: var(--fs-21);
  color: var(--c-ink-bright);
}

.page-about .about-role__text {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--c-ink);
}

.page-about .about-role__check {
  margin: 0;
  padding-top: 0.6rem;
  border-top: 1px dashed var(--c-rule);
  font-size: var(--fs-13);
  line-height: 1.75;
  color: var(--c-ink-dim);
}

/* ---------- 版本 ---------- */
.page-about .about-version__grid {
  display: grid;
  gap: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-version__text p {
  margin: 0 0 1rem;
}

.page-about .about-version__chips {
  display: grid;
  gap: 0.75rem;
  align-content: start;
}

.page-about .about-chip {
  position: relative;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.85rem 1.1rem;
  border: 1px solid var(--c-rule);
  border-radius: var(--r-s);
  background: rgba(20, 42, 92, 0.45);
  cursor: default;
  transition: border-color 240ms ease, background 240ms ease;
}

.page-about .about-chip:hover,
.page-about .about-chip:focus-visible {
  border-color: var(--c-pulse);
  background: rgba(20, 42, 92, 0.8);
}

.page-about .about-chip:focus-visible {
  outline: 2px solid var(--c-pulse);
  outline-offset: 2px;
}

.page-about .about-chip__no {
  font-size: var(--fs-17);
  letter-spacing: 0.08em;
  color: var(--c-pulse);
  flex: none;
}

.page-about .about-chip__tip {
  font-size: var(--fs-13);
  line-height: 1.7;
  color: var(--c-ink-dim);
}

.page-about .about-chip--current {
  border-color: var(--c-amber);
  background: rgba(255, 138, 61, 0.08);
}

.page-about .about-chip--current .about-chip__no {
  color: var(--c-amber);
}

.page-about .about-cycle {
  list-style: none;
  margin: clamp(2rem, 5vw, 3rem) 0 0;
  padding: 0;
  display: grid;
  gap: 1.25rem;
  counter-reset: none;
}

.page-about .about-cycle__step {
  position: relative;
  padding: 1rem 0 0 calc(var(--pa-rail) + 0.5rem);
  border-top: 1px dashed var(--c-rule);
}

.page-about .about-cycle__idx {
  position: absolute;
  left: 0;
  top: 1rem;
  font-size: var(--fs-13);
  letter-spacing: 0.12em;
  color: var(--c-galaxy-2);
}

.page-about .about-cycle__title {
  margin: 0 0 0.4rem;
  font-size: var(--fs-17);
  color: var(--c-ink-bright);
}

.page-about .about-cycle__step p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.8;
  color: var(--c-ink-dim);
}

/* ---------- 地域 ---------- */
.page-about .about-region__grid {
  display: grid;
  gap: clamp(1.5rem, 4vw, 2.5rem);
  align-items: start;
}

.page-about .about-region__text h2 {
  margin: 0.7rem 0 1rem;
  font-size: clamp(1.4rem, 3.6vw, 2.1rem);
  line-height: 1.28;
  color: var(--c-ink-bright);
}

.page-about .about-region__text .prose p {
  margin: 0 0 1rem;
}

.page-about .about-region__figure {
  margin: 0;
  position: relative;
}

.page-about .about-region__figure::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: var(--r-m);
  background: linear-gradient(180deg, rgba(11, 27, 58, 0) 40%, rgba(11, 27, 58, 0.72) 100%);
  pointer-events: none;
}

/* ---------- 引用规范 ---------- */
.page-about .about-cite__steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .about-cite__step {
  padding: 1.15rem 0 1.15rem 1.1rem;
  border-left: 1px solid var(--pa-line-soft);
  border-bottom: 1px dashed var(--c-rule);
}

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

.page-about .about-cite__title {
  margin: 0 0 0.45rem;
  font-size: var(--fs-17);
  color: var(--c-ink-bright);
}

.page-about .about-cite__step p {
  margin: 0;
  font-size: var(--fs-15);
  line-height: 1.85;
  color: var(--c-ink-dim);
}

.page-about .about-cite__tail {
  margin: 1.5rem 0 0;
  padding-top: 1rem;
  border-top: 1px solid var(--c-rule);
  font-size: var(--fs-15);
  line-height: 1.85;
  color: var(--c-ink);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  padding: clamp(1.5rem, 4vw, 2.5rem);
  display: grid;
  gap: 1.5rem;
  align-items: center;
  background:
    radial-gradient(70% 120% at 100% 0%, rgba(108, 63, 197, 0.3), transparent 68%),
    linear-gradient(135deg, rgba(20, 42, 92, 0.95), rgba(16, 31, 68, 0.7));
}

.page-about .about-cta__lead {
  margin: 0.6rem 0 0;
  max-width: 46ch;
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--c-ink);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.page-about .about-cta__actions .btn {
  white-space: nowrap;
}

/* ---------- 右侧章节刻度导航 ---------- */
.page-about .about-rail {
  display: none;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 900px) {
  .page-about {
    --pa-rail: 3rem;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  }

  .page-about .about-hero__stats {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.4fr);
    column-gap: clamp(2rem, 5vw, 4rem);
  }

  .page-about .about-split__aside {
    padding-right: 1.5rem;
    border-right: 1px dashed var(--c-rule);
  }

  .page-about .about-split--reverse .about-split__aside {
    order: 2;
    border-right: 0;
    border-left: 1px dashed var(--c-rule);
    padding-right: 0;
    padding-left: 1.5rem;
  }

  .page-about .about-split--reverse .about-split__body {
    order: 1;
  }

  .page-about .about-team__grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: start;
  }

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

  .page-about .about-version__grid {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
    column-gap: clamp(2rem, 5vw, 4rem);
  }

  .page-about .about-cycle {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1.5rem;
  }

  .page-about .about-cycle__step {
    border-top: 1px solid var(--c-galaxy);
  }

  .page-about .about-region__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    column-gap: clamp(2rem, 5vw, 4rem);
  }

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 2rem;
  }

  .page-about .about-cta__actions {
    justify-content: flex-end;
  }

  .page-about .about-rail {
    display: flex;
    position: fixed;
    right: 1.15rem;
    top: 50%;
    transform: translateY(-50%);
    z-index: 4;
    flex-direction: column;
    gap: 0.35rem;
  }

  .page-about .about-rail .rail__item {
    font-size: var(--fs-12);
    letter-spacing: 0.1em;
  }
}

@media (min-width: 1200px) {
  .page-about .about-rail {
    right: calc((100vw - min(1240px, 100vw - 2.5rem)) / 2 - 4.5rem);
  }
}

@media (max-width: 899px) {
  .page-about .about-timeline::before {
    top: 1rem;
    bottom: 1rem;
  }

  .page-about .about-note {
    margin-left: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-orbit {
    animation: none;
  }

  .page-about .about-stage__inner {
    animation: none;
  }

  .page-about .about-stage__bar span,
  .page-about .about-stage__node::before,
  .page-about .about-role,
  .page-about .about-chip {
    transition: none;
  }

  .page-about .about-role:hover {
    transform: none;
  }
}
<<<END>>>