.page-about {
  --about-rail: 176px;
  padding-top: var(--header-h);
  background: var(--c-white);
}

/* ---------- 首屏 ---------- */

.page-about .about-intro {
  background: var(--c-silver);
  border-bottom: 2px solid var(--c-ink);
  padding: 36px 0 48px;
}

.page-about .intro-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  margin-top: 28px;
}

.page-about .intro-lead {
  border-left: 6px solid var(--c-red);
  padding-left: 20px;
  min-width: 0;
}

.page-about .intro-lead h1 {
  font-size: 32px;
  line-height: 1.1;
  font-weight: 900;
  letter-spacing: -0.01em;
  margin: 12px 0 0;
  color: var(--c-ink);
  max-width: 16em;
}

.page-about .intro-text {
  margin: 20px 0 0;
  font-size: 16px;
  line-height: 1.75;
  color: var(--c-ink-2);
  max-width: 40em;
}

.page-about .intro-stats {
  display: grid;
  border: 2px solid var(--c-ink);
  background: var(--c-white);
  box-shadow: var(--shadow-hard);
  align-self: start;
}

.page-about .intro-stat {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 14px 18px;
  border-bottom: 2px solid var(--c-ink);
}

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

.page-about .intro-stat-num {
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
  color: var(--c-red);
  font-variant-numeric: tabular-nums;
}

.page-about .intro-stat-unit {
  font-size: 13px;
  color: var(--c-steel);
}

@media (min-width: 860px) {
  .page-about .about-intro {
    padding: 44px 0 60px;
  }
  .page-about .intro-grid {
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: 56px;
    align-items: end;
  }
  .page-about .intro-lead {
    padding-left: 26px;
  }
  .page-about .intro-lead h1 {
    font-size: 54px;
  }
  .page-about .intro-text {
    font-size: 17px;
  }
}

/* ---------- 主布局与左侧刻度 ---------- */

.page-about .about-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  padding: 52px 0 64px;
}

.page-about .about-rail {
  display: none;
}

.page-about .rail-title {
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--c-steel);
}

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

.page-about .rail-list::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 14px;
  bottom: 14px;
  width: 2px;
  background: var(--c-line);
  opacity: 0.5;
}

.page-about .rail-list li {
  position: relative;
}

.page-about .rail-list a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 0;
  text-decoration: none;
  color: var(--c-ink-2);
  font-size: 13px;
  transition: color 200ms ease;
}

.page-about .rail-node {
  width: 24px;
  height: 24px;
  flex: 0 0 24px;
  border: 2px solid var(--c-line);
  background: var(--c-white);
  border-radius: 50%;
  position: relative;
  z-index: 1;
  transition: border-color 200ms ease, background 200ms ease;
}

.page-about .rail-num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--c-steel);
  font-variant-numeric: tabular-nums;
  transition: color 200ms ease;
}

.page-about .rail-label {
  min-width: 0;
}

.page-about .rail-list a:hover {
  color: var(--c-red);
}

.page-about .rail-list a:hover .rail-node {
  border-color: var(--c-red);
  background: var(--c-cyan);
}

.page-about .rail-list a:hover .rail-num {
  color: var(--c-red);
}

@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 64px;
    padding: 64px 0 80px;
  }
  .page-about .about-rail {
    display: block;
  }
  .page-about .rail-sticky {
    position: sticky;
    top: calc(var(--header-h) + 40px);
  }
}

/* ---------- 阶段模块 ---------- */

.page-about .about-flow {
  min-width: 0;
  display: grid;
  gap: 56px;
}

.page-about .stage {
  min-width: 0;
  position: relative;
}

.page-about .stage + .stage {
  padding-top: 56px;
  border-top: 2px solid var(--c-silver);
}

.page-about .stage-head {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 26px;
}

.page-about .stage-index {
  flex: 0 0 42px;
  width: 42px;
  height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  border: 2px solid var(--c-line);
  color: var(--c-steel);
  font-variant-numeric: tabular-nums;
  transition: border-color 420ms ease, background 420ms ease, color 420ms ease;
}

.page-about .stage.is-on .stage-index {
  border-color: var(--c-red);
  background: var(--c-red);
  color: var(--c-white);
}

.page-about .stage-heading {
  min-width: 0;
  flex: 1 1 auto;
}

.page-about .stage-heading h2 {
  margin: 6px 0 0;
  font-size: 23px;
  line-height: 1.2;
  font-weight: 900;
  color: var(--c-ink);
}

.page-about .stage-note {
  display: none;
}

@media (min-width: 860px) {
  .page-about .about-flow {
    gap: 72px;
  }
  .page-about .stage + .stage {
    padding-top: 72px;
  }
  .page-about .stage-heading h2 {
    font-size: 32px;
  }
  .page-about .stage-note {
    display: block;
    writing-mode: vertical-rl;
    font-size: 12px;
    letter-spacing: 0.22em;
    color: var(--c-steel);
    margin-left: auto;
    padding-top: 6px;
    flex: 0 0 auto;
  }
}

.page-about .stage-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
}

.page-about .stage-stack {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
}

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

.page-about .stage-main p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.78;
  color: var(--c-ink-2);
  max-width: 62ch;
}

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

.page-about .stage-main a {
  color: var(--c-red);
  text-decoration: none;
  border-bottom: 2px solid var(--c-red);
  padding-bottom: 1px;
}

.page-about .stage-main a:hover {
  color: var(--c-red-deep);
  border-color: var(--c-red-deep);
}

@media (min-width: 900px) {
  .page-about .stage-grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(230px, 1fr);
    gap: 52px;
    align-items: start;
  }
}

/* ---------- 事实清单 ---------- */

.page-about .stage-facts {
  margin: 0;
  border: 2px solid var(--c-ink);
  background: var(--c-white);
  box-shadow: var(--shadow-hard);
  padding: 22px 22px 8px;
}

.page-about .stage-facts dt {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--c-red);
  margin-bottom: 6px;
}

.page-about .stage-facts dd {
  margin: 0 0 18px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--c-ink-2);
}

.page-about .stage-facts dd:last-child {
  margin-bottom: 12px;
}

/* ---------- 版本模块 ---------- */

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

.page-about .version-item {
  border: 2px solid var(--c-ink);
  background: var(--c-white);
  box-shadow: var(--shadow-hard);
}

.page-about .version-item--current {
  border-color: var(--c-red);
  box-shadow: 6px 6px 0 rgba(200, 16, 46, 0.28);
}

.page-about .version-summary {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px 14px;
  padding: 20px 22px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .version-summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 20px;
  line-height: 1;
  color: var(--c-steel);
  transition: transform 200ms ease, color 200ms ease;
}

.page-about .version-item[open] .version-summary::after {
  content: "–";
  color: var(--c-red);
}

.page-about .version-summary:hover::after {
  color: var(--c-red);
}

.page-about .version-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  padding: 4px 10px;
  border: 2px solid var(--c-ink);
  background: var(--c-silver);
  color: var(--c-ink);
  white-space: nowrap;
}

.page-about .version-tag--current {
  background: var(--c-red);
  border-color: var(--c-red);
  color: var(--c-white);
}

.page-about .version-title {
  font-size: 17px;
  font-weight: 800;
  color: var(--c-ink);
  line-height: 1.3;
}

.page-about .version-body {
  padding: 0 22px 22px;
  border-top: 2px solid var(--c-silver);
}

.page-about .version-body p {
  margin: 16px 0 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--c-ink-2);
}

.page-about .version-aside {
  font-size: 13px !important;
  color: var(--c-steel) !important;
  padding-left: 14px;
  border-left: 3px solid var(--c-cyan);
}

/* ---------- 内容生产流程 ---------- */

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

.page-about .flow-list li {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 18px;
  padding: 20px 0;
  border-bottom: 2px solid var(--c-silver);
}

.page-about .flow-list li:first-child {
  padding-top: 0;
}

.page-about .flow-list li:last-child {
  border-bottom: 0;
  padding-bottom: 4px;
}

.page-about .flow-num {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--c-red);
  font-variant-numeric: tabular-nums;
}

.page-about .flow-list h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 800;
  color: var(--c-ink);
}

.page-about .flow-list p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--c-ink-2);
  max-width: 60ch;
}

.page-about .flow-tail {
  margin-top: 22px !important;
  padding-top: 18px;
  border-top: 2px solid var(--c-ink);
  font-size: 15px;
}

/* ---------- 暗色指标面板 ---------- */

.page-about .aside-metric {
  padding: 26px 24px 28px;
}

.page-about .aside-metric-label {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--c-cyan);
}

.page-about .aside-metric-num {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: 46px;
  font-weight: 700;
  line-height: 1;
  color: var(--c-white);
  font-variant-numeric: tabular-nums;
}

.page-about .aside-metric-num span {
  font-size: 24px;
  color: var(--c-cyan);
  margin-left: 4px;
}

.page-about .aside-metric-desc {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: rgba(232, 236, 241, 0.76);
}

/* ---------- 目录周期清单 ---------- */

.page-about .cycle-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  border-top: 2px solid var(--c-ink);
}

.page-about .cycle-list li {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 16px 0;
  border-bottom: 2px solid var(--c-silver);
}

.page-about .cycle-key {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-red);
}

.page-about .cycle-val {
  font-size: 15px;
  line-height: 1.7;
  color: var(--c-ink-2);
}

@media (min-width: 720px) {
  .page-about .cycle-list li {
    grid-template-columns: 150px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }
}

/* ---------- 图片 ---------- */

.page-about .stage-figure {
  margin: 0;
  min-width: 0;
}

.page-about .stage-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 2px solid var(--c-ink);
  box-shadow: var(--shadow-hard);
  object-fit: cover;
  background: var(--c-ink-2);
}

.page-about .stage-figure figcaption {
  margin-top: 10px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--c-steel);
}

.page-about .stage-figure--wide img {
  aspect-ratio: 2 / 1;
  border-color: var(--c-line);
  box-shadow: var(--shadow-hard-dark);
}

/* ---------- 团队数据带 ---------- */

.page-about .team-band {
  position: relative;
  overflow: hidden;
  background: var(--grad-night);
  border-top: 2px solid var(--c-line);
  border-bottom: 2px solid var(--c-line);
  padding: 52px 0 56px;
}

.page-about .team-band::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(46, 74, 102, 0.4) 1px, transparent 1px),
    linear-gradient(90deg, rgba(46, 74, 102, 0.4) 1px, transparent 1px);
  background-size: 48px 48px;
  opacity: 0.55;
  pointer-events: none;
}

.page-about .team-band .container {
  position: relative;
  z-index: 1;
}

.page-about .team-band-title {
  margin: 0 0 24px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--c-cyan);
}

.page-about .team-grid {
  display: grid;
  grid-template-columns: 1fr;
}

.page-about .team-cell {
  padding: 22px 0;
  border-top: 2px solid var(--c-line);
}

.page-about .team-cell:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .team-cell:last-child {
  padding-bottom: 0;
}

.page-about .team-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 50px;
  font-weight: 700;
  line-height: 1;
  color: var(--c-white);
  font-variant-numeric: tabular-nums;
}

.page-about .team-label {
  display: block;
  margin-top: 6px;
  font-size: 15px;
  font-weight: 800;
  color: var(--c-cyan);
}

.page-about .team-cell p {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.72;
  color: rgba(232, 236, 241, 0.74);
  max-width: 34ch;
}

@media (min-width: 760px) {
  .page-about .team-band {
    padding: 64px 0;
  }
  .page-about .team-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .team-cell {
    padding: 0 34px;
    border-top: 0;
    border-left: 2px solid var(--c-line);
  }
  .page-about .team-cell:first-child {
    padding-left: 0;
    border-left: 0;
  }
  .page-about .team-cell:last-child {
    padding-right: 0;
  }
}

/* ---------- 收束区 ---------- */

.page-about .about-closing {
  position: relative;
  background: var(--c-ink);
  padding: 52px 0 60px;
}

.page-about .about-closing::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 8px;
  background: var(--c-red);
}

.page-about .closing-inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
}

.page-about .closing-lead h2 {
  margin: 14px 0 16px;
  font-size: 25px;
  line-height: 1.24;
  font-weight: 900;
  color: var(--c-white);
}

.page-about .closing-lead p {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: rgba(232, 236, 241, 0.78);
  max-width: 44ch;
}

.page-about .eyebrow--light {
  color: var(--c-cyan);
}

.page-about .closing-facts {
  margin: 0;
  border-top: 2px solid var(--c-line);
  padding-top: 6px;
}

.page-about .closing-facts dt {
  margin: 18px 0 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--c-cyan);
}

.page-about .closing-facts dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
  color: var(--c-silver);
  word-break: break-word;
}

.page-about .closing-cta {
  display: inline-flex;
  margin-top: 26px;
  text-decoration: none;
}

@media (min-width: 900px) {
  .page-about .about-closing {
    padding: 64px 0 76px;
  }
  .page-about .closing-inner {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 68px;
    align-items: start;
  }
  .page-about .closing-lead h2 {
    font-size: 34px;
  }
}
<<<END>>>