.page-about {
  --about-rail-w: 210px;
  --about-edge: 2px solid var(--line);
  position: relative;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(28px, 5vw, 56px) 0 clamp(44px, 7vw, 84px);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  left: -15%;
  right: -15%;
  top: -35%;
  height: 130%;
  background:
    radial-gradient(42% 52% at 16% 24%, rgba(53, 242, 160, 0.17), transparent 68%),
    radial-gradient(44% 54% at 84% 8%, rgba(60, 140, 255, 0.19), transparent 70%),
    radial-gradient(38% 46% at 62% 62%, rgba(107, 227, 255, 0.10), transparent 72%);
  pointer-events: none;
  animation: about-drift 12s var(--ease) infinite alternate;
}

@keyframes about-drift {
  from { transform: translate3d(0, 0, 0) }
  to { transform: translate3d(-3%, 2.5%, 0) }
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
}

.page-about .crumb-here {
  color: var(--mute);
}

.page-about .about-title {
  margin: 14px 0 clamp(20px, 3vw, 30px);
  max-width: 16ch;
}

.page-about .about-title .hl {
  color: var(--neon);
}

.page-about .about-hero-body {
  display: grid;
  gap: 28px;
}

.page-about .about-hero-body .lede {
  max-width: 60ch;
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin: 0;
}

.page-about .fact {
  border: var(--about-edge);
  background: var(--ink-2);
  padding: 14px 12px;
  box-shadow: var(--shadow-soft);
}

.page-about .fact dt {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--mute);
  margin-bottom: 8px;
}

.page-about .fact dd {
  margin: 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(19px, 3.4vw, 27px);
  line-height: 1;
  color: var(--neon);
}

@media (min-width: 900px) {
  .page-about .about-hero-body {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    align-items: end;
    gap: 52px;
  }
}

/* ---------- 主体骨架 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  padding-bottom: clamp(60px, 9vw, 120px);
}

@media (min-width: 1024px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(40px, 5vw, 76px);
    align-items: start;
  }
}

/* ---------- 章节导轨 ---------- */
.page-about .rail-title {
  margin: 0 0 12px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--mute);
}

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

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

.page-about .rail-list a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 15px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--mute);
  text-decoration: none;
  white-space: nowrap;
  font-size: 13px;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .rail-list a b {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--blue);
}

.page-about .rail-list a:hover,
.page-about .rail-list a:focus-visible {
  color: var(--neon);
  border-color: var(--neon);
  background: rgba(53, 242, 160, 0.08);
}

@media (min-width: 1024px) {
  .page-about .about-rail {
    position: sticky;
    top: 118px;
  }

  .page-about .rail-list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    border-left: 2px solid var(--line);
  }

  .page-about .rail-list a {
    width: 100%;
    border: 0;
    border-radius: 0;
    padding: 10px 10px 10px 16px;
    position: relative;
    justify-content: flex-start;
  }

  .page-about .rail-list a::before {
    content: "";
    position: absolute;
    left: -2px;
    top: 7px;
    bottom: 7px;
    width: 2px;
    background: transparent;
    transition: background 0.2s var(--ease);
  }

  .page-about .rail-list a:hover::before,
  .page-about .rail-list a:focus-visible::before {
    background: var(--neon);
  }
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  scroll-margin-top: 112px;
}

.page-about .about-section + .about-section {
  margin-top: clamp(44px, 6vw, 84px);
  padding-top: clamp(40px, 6vw, 76px);
  border-top: 1px solid var(--line);
}

.page-about .about-head {
  margin-bottom: clamp(24px, 4vw, 40px);
}

.page-about .about-num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--neon);
  padding-bottom: 6px;
  margin-bottom: 14px;
  border-bottom: 2px solid var(--neon);
}

.page-about .about-head h2 {
  margin: 0 0 12px;
}

.page-about .about-lead {
  margin: 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.75;
  color: var(--mute);
}

.page-about .about-footnote {
  margin: 26px 0 0;
  padding-left: 16px;
  border-left: 2px solid var(--blue);
  max-width: 68ch;
  font-size: 14px;
  line-height: 1.8;
  color: var(--mute);
}

/* ---------- 01 沿革 ---------- */
.page-about .about-origin {
  display: grid;
  gap: 28px;
  margin-bottom: clamp(30px, 5vw, 48px);
}

@media (min-width: 900px) {
  .page-about .about-origin {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 44px;
    align-items: start;
  }
}

.page-about .about-prose p {
  margin: 0 0 16px;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--mute);
}

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

.page-about .about-media {
  margin: 0;
  border: var(--about-edge);
  background: var(--ink-2);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.page-about .about-media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
}

.page-about .about-media figcaption {
  padding: 11px 15px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.6;
  color: var(--mute);
}

.page-about .about-media--wide {
  margin-bottom: clamp(24px, 4vw, 36px);
}

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

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: linear-gradient(180deg, rgba(255, 138, 61, 0.6), rgba(53, 242, 160, 0.55));
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 26px 34px;
}

.page-about .tl-item:last-child {
  padding-bottom: 0;
}

.page-about .tl-dot {
  position: absolute;
  left: 0;
  top: 4px;
  width: 16px;
  height: 16px;
  background: var(--amber);
  border: 2px solid var(--ink);
  transform: rotate(45deg);
}

.page-about .tl-dot--now {
  background: var(--neon);
}

.page-about .tl-year {
  display: block;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--amber);
  margin-bottom: 4px;
}

.page-about .tl-year--now {
  color: var(--neon);
}

.page-about .tl-body h3 {
  margin: 0 0 6px;
  font-size: 1.05rem;
  color: var(--white);
}

.page-about .tl-body p {
  margin: 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--mute);
}

@media (min-width: 720px) {
  .page-about .tl-item {
    display: grid;
    grid-template-columns: 92px minmax(0, 1fr);
    column-gap: 20px;
    align-items: start;
  }

  .page-about .tl-year {
    grid-column: 1;
    margin-bottom: 0;
    padding-top: 2px;
  }

  .page-about .tl-body {
    grid-column: 2;
  }
}

/* ---------- 02 分区剖面 ---------- */
.page-about .about-layers {
  display: grid;
  gap: 14px;
}

@media (min-width: 760px) {
  .page-about .about-layers {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .layer {
  position: relative;
  border: var(--about-edge);
  background: var(--ink-2);
  padding: 24px 20px 22px;
  box-shadow: var(--shadow-soft);
}

.page-about .layer::after {
  content: "";
  position: absolute;
  top: -2px;
  right: 20px;
  width: 44px;
  height: 2px;
  background: var(--neon);
}

.page-about .layer-tag {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--blue);
}

.page-about .layer h3 {
  margin: 0 0 8px;
  font-size: 1.15rem;
}

.page-about .layer p:last-child {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--mute);
}

/* ---------- 03 三层分级 ---------- */
.page-about .about-tiers {
  display: grid;
  gap: 28px;
}

@media (min-width: 960px) {
  .page-about .about-tiers {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    gap: 44px;
    align-items: start;
  }
}

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

.page-about .tier {
  position: relative;
  border: var(--about-edge);
  background: var(--ink-2);
  padding: 20px 22px 18px 26px;
}

.page-about .tier::before {
  content: "";
  position: absolute;
  left: -2px;
  top: -2px;
  bottom: -2px;
  width: 6px;
}

.page-about .tier--core::before { background: var(--neon); }
.page-about .tier--grow::before { background: var(--blue); }
.page-about .tier--new::before { background: var(--amber); }

.page-about .tier-name {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--white);
}

.page-about .tier-desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--mute);
}

.page-about .about-note {
  margin-top: 28px;
  padding: 24px;
}

.page-about .about-note h3 {
  margin: 0 0 10px;
  font-size: 1.1rem;
}

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

.page-about .about-note a {
  color: var(--neon);
}

/* ---------- 04 三种看法 ---------- */
.page-about .dim-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 18px;
}

.page-about .dim-tab {
  display: inline-block;
  padding: 9px 20px;
  border: 2px solid var(--line);
  color: var(--mute);
  text-decoration: none;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .dim-tab:hover,
.page-about .dim-tab:focus-visible {
  color: var(--neon);
  border-color: var(--neon);
  background: rgba(53, 242, 160, 0.07);
}

.page-about .dim-panel {
  display: none;
  scroll-margin-top: 130px;
  border: var(--about-edge);
  background: var(--ink-2);
  padding: clamp(24px, 4vw, 34px);
  box-shadow: var(--shadow);
}

.page-about .dim-panel:first-of-type {
  display: block;
}

.page-about .dim-panel:target {
  display: block;
}

.page-about .dim-panels:has(.dim-panel:target) .dim-panel:not(:target) {
  display: none;
}

.page-about .dim-num {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: clamp(2.2rem, 6vw, 3.4rem);
  font-weight: 700;
  line-height: 1;
  color: var(--neon);
}

.page-about .dim-num span {
  margin-left: 10px;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--mute);
}

.page-about .dim-panel h3 {
  margin: 0 0 14px;
  font-size: 1.2rem;
}

.page-about .dim-panel p {
  margin: 0 0 14px;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mute);
}

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

/* ---------- 05 统计节奏 ---------- */
.page-about .about-flow-rows {
  display: grid;
  border-top: 2px solid var(--line);
}

.page-about .flow-row {
  padding: 24px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .flow-step {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--blue);
}

.page-about .flow-row h3 {
  margin: 0 0 8px;
  font-size: 1.3rem;
}

.page-about .flow-row p:last-child {
  margin: 0;
  max-width: 46ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--mute);
}

@media (min-width: 860px) {
  .page-about .about-flow-rows {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    border-bottom: 2px solid var(--line);
  }

  .page-about .flow-row {
    padding: 26px 26px 26px 0;
    border-bottom: 0;
    border-right: 1px solid var(--line);
  }

  .page-about .flow-row + .flow-row {
    padding-left: 26px;
  }

  .page-about .flow-row:last-child {
    border-right: 0;
    padding-right: 0;
  }
}

/* ---------- 06 团队 ---------- */
.page-about .about-team {
  display: grid;
  gap: 14px;
}

@media (min-width: 780px) {
  .page-about .about-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .team-card {
  border: var(--about-edge);
  border-top-width: 4px;
  border-top-color: var(--blue);
  background: var(--ink-2);
  padding: 22px 20px;
}

.page-about .team-card:nth-child(2) { border-top-color: var(--neon); }
.page-about .team-card:nth-child(3) { border-top-color: var(--amber); }

.page-about .team-name {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--white);
}

.page-about .team-card p:last-child {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--mute);
}

/* ---------- 07 文档 ---------- */
.page-about .about-docs {
  display: grid;
  gap: 24px;
  border: var(--about-edge);
  background: var(--ink-2);
  padding: 24px;
  box-shadow: var(--shadow-soft);
}

@media (min-width: 800px) {
  .page-about .about-docs {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: 40px;
    padding: 34px;
  }
}

.page-about .doc-label {
  margin: 0;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--mute);
}

.page-about .doc-version {
  margin: 8px 0 10px;
  font-family: var(--font-mono);
  font-size: clamp(1.8rem, 4vw, 2.2rem);
  font-weight: 700;
  line-height: 1;
  color: var(--neon);
}

.page-about .doc-meta {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mute);
  border-top: 1px solid var(--line);
  padding-top: 12px;
}

.page-about .doc-body p {
  margin: 0 0 16px;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mute);
}

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

.page-about .doc-body a {
  color: var(--neon);
}

/* ---------- 08 下一步 ---------- */
.page-about .next-links {
  display: grid;
  gap: 14px;
}

@media (min-width: 820px) {
  .page-about .next-links {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .next-link {
  display: block;
  border: var(--about-edge);
  background: var(--ink-2);
  padding: 26px 22px;
  color: inherit;
  text-decoration: none;
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease), transform 0.2s var(--ease);
}

.page-about .next-link:hover,
.page-about .next-link:focus-visible {
  border-color: var(--neon);
  background: rgba(53, 242, 160, 0.06);
  transform: translateY(-4px);
}

.page-about .next-kicker {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--blue);
}

.page-about .next-link h3 {
  margin: 0 0 10px;
  font-size: 1.25rem;
  color: var(--white);
}

.page-about .next-link p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--mute);
}

.page-about .about-contact {
  margin-top: 26px;
  padding: 26px 24px;
}

.page-about .contact-kicker {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .contact-main {
  margin: 0 0 10px;
  max-width: 70ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--white);
}

.page-about .contact-main a {
  color: var(--neon);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .contact-sub {
  margin: 0;
  font-size: 14px;
  color: var(--mute);
}

/* ---------- 降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-hero::before {
    animation: none;
  }

  .page-about .next-link {
    transition: none;
  }

  .page-about .next-link:hover,
  .page-about .next-link:focus-visible {
    transform: none;
  }
}
<<<END>>>