.page-about {
  --about-hair: 1px solid var(--pb-line);
  --about-gutter: clamp(16px, 4.2vw, 44px);
  --about-gap: clamp(20px, 3.2vw, 36px);
  background: var(--pb-ink-950);
  color: var(--pb-paper);
  overflow-x: hidden;
}

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

.page-about .pb-section {
  padding-top: clamp(48px, 7vw, 88px);
  padding-bottom: clamp(48px, 7vw, 88px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding-top: calc(var(--pb-header-h) + 26px);
  padding-bottom: clamp(28px, 4vw, 44px);
  border-bottom: var(--about-hair);
  background-image:
    linear-gradient(to right, rgba(27, 46, 77, 0.55) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(27, 46, 77, 0.55) 1px, transparent 1px);
  background-size: 96px 96px;
  background-position: 0 0;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--pb-pulse), transparent);
  opacity: 0.6;
}

.page-about .pb-breadcrumb {
  font-family: var(--pb-font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--pb-ash);
  margin-bottom: clamp(24px, 4vw, 44px);
}

.page-about .pb-breadcrumb a {
  color: var(--pb-ash);
  text-decoration: none;
}

.page-about .pb-breadcrumb a:hover,
.page-about .pb-breadcrumb a:focus-visible {
  color: var(--pb-pulse);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(26px, 4vw, 40px);
  align-items: end;
}

.page-about .about-hero__intro .pb-h1 {
  margin: 10px 0 18px;
  max-width: 15em;
}

.page-about .about-hero__intro .pb-lead {
  max-width: 34em;
  color: var(--pb-ash);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero__figure {
  border: var(--about-hair);
  background: var(--pb-ink-900);
  padding: 8px;
}

.page-about .about-hero__figure .pb-figure__caption {
  font-family: var(--pb-font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--pb-ash);
  padding: 10px 4px 2px;
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(32px, 5vw, 52px) 0 0;
  background: var(--pb-line);
  border: var(--about-hair);
}

.page-about .about-stats__item {
  background: var(--pb-ink-950);
  padding: 16px 14px;
}

.page-about .about-stats dt {
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--pb-ash);
  text-transform: uppercase;
}

.page-about .about-stats dd {
  margin: 8px 0 0;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.page-about .about-stats__num {
  font-family: var(--pb-font-mono);
  font-size: clamp(26px, 4vw, 34px);
  font-weight: 700;
  line-height: 1;
  color: var(--pb-paper);
}

.page-about .about-stats__unit {
  font-size: 12px;
  color: var(--pb-pulse);
}

/* ---------- 起点 ---------- */
.page-about .about-start .pb-h2 {
  margin: 8px 0 20px;
}

.page-about .about-start .pb-prose p {
  margin: 0 0 16px;
  max-width: 36em;
}

.page-about .about-start__aside {
  position: relative;
  border-top: 2px solid var(--pb-signal);
  padding-top: 18px;
  margin-top: 4px;
}

.page-about .about-start__aside .pb-rotate-note {
  font-family: var(--pb-font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--pb-ash);
  margin: 0 0 14px;
}

.page-about .about-ledger {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-ledger__row {
  display: grid;
  grid-template-columns: 78px 1fr;
  gap: 12px;
  align-items: start;
  padding: 14px 0;
  border-bottom: 1px dashed var(--pb-line);
}

.page-about .about-ledger__row:first-child {
  border-top: 1px dashed var(--pb-line);
}

.page-about .about-ledger__num {
  font-family: var(--pb-font-mono);
  font-size: 24px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--pb-index);
}

.page-about .about-ledger__text {
  font-size: 14px;
  line-height: 1.75;
  color: var(--pb-ash);
}

/* ---------- 三条主线 ---------- */
.page-about .about-lines__head {
  max-width: 44em;
}

.page-about .about-lines__lead {
  margin-top: 14px;
}

.page-about .about-lines__stack {
  display: grid;
  gap: 18px;
  margin-top: clamp(28px, 4vw, 44px);
}

.page-about .line-card {
  --lc: var(--pb-signal);
  position: relative;
  padding: 22px 18px 20px;
  border: var(--about-hair);
  background: linear-gradient(160deg, var(--pb-ink-900), var(--pb-ink-950));
  outline: none;
  transition: border-color 200ms var(--pb-ease), transform 200ms var(--pb-ease);
}

.page-about .line-card::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  height: 2px;
  width: 34px;
  background: var(--lc);
  transition: width 260ms var(--pb-ease);
}

.page-about .line-card--b {
  --lc: var(--pb-pulse);
}

.page-about .line-card--c {
  --lc: var(--pb-index);
}

.page-about .line-card:hover,
.page-about .line-card:focus-visible,
.page-about .line-card:focus-within {
  border-color: var(--lc);
}

.page-about .line-card:hover::before,
.page-about .line-card:focus-visible::before {
  width: 100%;
}

.page-about .line-card__idx {
  font-family: var(--pb-font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--lc);
  margin: 0 0 10px;
}

.page-about .line-card .pb-h3 {
  margin: 0 0 12px;
}

.page-about .line-card__body {
  margin: 0 0 14px;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--pb-ash);
}

.page-about .line-card__feed {
  margin: 0;
  padding-top: 12px;
  border-top: 1px dashed var(--pb-line);
  font-family: var(--pb-font-mono);
  font-size: 11.5px;
  letter-spacing: 0.03em;
  color: var(--pb-paper);
  opacity: 0.82;
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline__head {
  display: grid;
  gap: 10px;
}

.page-about .about-timeline__hint {
  font-family: var(--pb-font-mono);
  font-size: 12px;
  color: var(--pb-pulse);
  letter-spacing: 0.04em;
  margin: 0;
}

.page-about .about-tl {
  margin-top: clamp(26px, 4vw, 40px);
  border-top: var(--about-hair);
  padding-top: 6px;
}

.page-about .about-tl__node {
  position: relative;
  border-bottom: 1px dashed var(--pb-line);
}

.page-about .about-tl__head {
  display: grid;
  grid-template-columns: 14px auto 1fr;
  align-items: center;
  gap: 10px;
  padding: 16px 4px;
  cursor: pointer;
  list-style: none;
  outline: none;
}

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

.page-about .about-tl__dot {
  width: 9px;
  height: 9px;
  background: var(--pb-line);
  transition: background 200ms var(--pb-ease);
}

.page-about .about-tl__code {
  font-family: var(--pb-font-mono);
  font-size: 12px;
  color: var(--pb-index);
  letter-spacing: 0.1em;
}

.page-about .about-tl__phase {
  font-size: 15px;
  font-weight: 600;
  color: var(--pb-paper);
}

.page-about .about-tl__head:hover .about-tl__dot,
.page-about .about-tl__head:focus-visible .about-tl__dot {
  background: var(--pb-pulse);
}

.page-about .about-tl__node[open] > .about-tl__head .about-tl__dot {
  background: var(--pb-signal);
}

.page-about .about-tl__node[open] > .about-tl__head .about-tl__phase {
  color: var(--pb-signal);
}

.page-about .about-tl__body {
  padding: 0 4px 18px 38px;
}

.page-about .about-tl__body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--pb-ash);
  max-width: 42em;
}

/* ---------- 团队 ---------- */
.page-about .about-team__lead {
  margin: 14px 0 22px;
}

.page-about .about-team__cards {
  display: grid;
  gap: 12px;
}

.page-about .team-card {
  border: var(--about-hair);
  border-left: 2px solid var(--pb-tag-a);
  background: var(--pb-ink-900);
}

.page-about .team-card:nth-child(2) {
  border-left-color: var(--pb-tag-b);
}

.page-about .team-card:nth-child(3) {
  border-left-color: var(--pb-tag-c);
}

.page-about .team-card__head {
  display: grid;
  grid-template-columns: 30px 1fr;
  align-items: center;
  gap: 10px;
  padding: 15px 16px;
  cursor: pointer;
  list-style: none;
  outline: none;
}

.page-about .team-card__head::-webkit-details-marker {
  display: none;
}

.page-about .team-card__head:focus-visible {
  box-shadow: inset 0 0 0 1px var(--pb-pulse);
}

.page-about .team-card__idx {
  font-family: var(--pb-font-mono);
  font-size: 13px;
  color: var(--pb-index);
  border: 1px solid var(--pb-line);
  text-align: center;
  line-height: 22px;
  height: 22px;
}

.page-about .team-card .pb-h3 {
  margin: 0;
  font-size: 17px;
}

.page-about .team-card__list {
  margin: 0;
  padding: 0 18px 16px 40px;
  list-style: none;
}

.page-about .team-card__list li {
  position: relative;
  font-size: 14px;
  line-height: 1.8;
  color: var(--pb-ash);
  padding-left: 14px;
  margin-bottom: 6px;
}

.page-about .team-card__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 11px;
  width: 5px;
  height: 5px;
  background: var(--pb-pulse);
}

.page-about .about-team__figure {
  border: var(--about-hair);
  background: var(--pb-ink-900);
  padding: 8px;
  margin: clamp(24px, 4vw, 0) 0 0;
}

.page-about .about-team__figure .pb-figure__caption {
  font-family: var(--pb-font-mono);
  font-size: 11px;
  color: var(--pb-ash);
  padding: 10px 4px 2px;
}

/* ---------- 来源与合作 ---------- */
.page-about .about-source__figure {
  border: var(--about-hair);
  background: var(--pb-ink-900);
  padding: 8px;
  margin: 0 0 clamp(24px, 4vw, 0);
}

.page-about .about-source__figure .pb-figure__caption {
  font-family: var(--pb-font-mono);
  font-size: 11px;
  color: var(--pb-ash);
  padding: 10px 4px 2px;
}

.page-about .about-source__main .pb-h2 {
  margin: 8px 0 18px;
}

.page-about .about-source__main .pb-prose p {
  margin: 0 0 14px;
  max-width: 36em;
}

.page-about .about-flow {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  border-top: var(--about-hair);
}

.page-about .about-flow__step {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 10px;
  align-items: baseline;
  padding: 12px 0;
  border-bottom: 1px dashed var(--pb-line);
  font-size: 14px;
  line-height: 1.7;
  color: var(--pb-ash);
}

.page-about .about-flow__n {
  font-family: var(--pb-font-mono);
  font-size: 12px;
  color: var(--pb-pulse);
  letter-spacing: 0.1em;
}

.page-about .about-source__link {
  margin-top: 22px;
}

/* ---------- 节奏 ---------- */
.page-about .about-rhythm__head .pb-h2 {
  margin: 8px 0 0;
}

.page-about .about-rhythm__list {
  margin: clamp(26px, 4vw, 40px) 0 0;
  border-top: var(--about-hair);
}

.page-about .about-rhythm__row {
  display: grid;
  gap: 6px;
  padding: 20px 0;
  border-bottom: var(--about-hair);
}

.page-about .about-rhythm__row dt {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
}

.page-about .about-rhythm__num {
  font-family: var(--pb-font-mono);
  font-size: 22px;
  font-weight: 700;
  color: var(--pb-paper);
  letter-spacing: -0.01em;
}

.page-about .about-rhythm__name {
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--pb-signal);
  text-transform: uppercase;
}

.page-about .about-rhythm__row dd {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--pb-ash);
  max-width: 40em;
}

/* ---------- 里程碑 ---------- */
.page-about .about-milestone__intro .pb-h2 {
  margin: 8px 0 16px;
}

.page-about .about-milestone__intro .pb-prose {
  max-width: 28em;
}

.page-about .about-index {
  list-style: none;
  margin: clamp(24px, 4vw, 0) 0 0;
  padding: 0;
  border-top: var(--about-hair);
}

.page-about .about-index__item {
  display: grid;
  grid-template-columns: 46px 1fr;
  gap: 12px;
  padding: 18px 0;
  border-bottom: var(--about-hair);
}

.page-about .about-index__code {
  font-family: var(--pb-font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--pb-index);
  padding-top: 3px;
}

.page-about .about-index__text .pb-h3 {
  margin: 0 0 6px;
  font-size: 17px;
}

.page-about .about-index__text p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--pb-ash);
}

/* ---------- 收尾 ---------- */
.page-about .about-closing {
  margin-top: clamp(34px, 5vw, 56px);
  padding: clamp(22px, 3.5vw, 32px);
  border: var(--about-hair);
  border-left: 3px solid var(--pb-signal);
  background: var(--pb-ink-900);
  display: grid;
  gap: 18px;
}

.page-about .about-closing__text {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--pb-paper);
  max-width: 40em;
}

.page-about .about-closing__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .pb-pulse-line {
  margin-top: clamp(30px, 4vw, 44px);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-rhythm__row {
    grid-template-columns: 240px 1fr;
    gap: 28px;
    align-items: start;
  }

  .page-about .about-tl {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 28px;
    border-top: 0;
    padding-top: 0;
  }

  .page-about .about-tl__node {
    border-bottom: 1px dashed var(--pb-line);
    border-top: var(--about-hair);
  }

  .page-about .about-team__cards {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1px;
    background: var(--pb-line);
    border: var(--about-hair);
  }

  .page-about .team-card {
    border: 0;
    border-top: 2px solid var(--pb-tag-a);
    background: var(--pb-ink-900);
  }

  .page-about .team-card:nth-child(2) {
    border-top-color: var(--pb-tag-b);
    border-left: 0;
  }

  .page-about .team-card:nth-child(3) {
    border-top-color: var(--pb-tag-c);
    border-left: 0;
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero__grid {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .about-hero__intro {
    grid-column: 1 / span 5;
    padding-bottom: 8px;
  }

  .page-about .about-hero__figure {
    grid-column: 6 / span 7;
  }

  .page-about .about-start__grid,
  .page-about .about-team__grid,
  .page-about .about-source__grid,
  .page-about .about-milestone__grid {
    align-items: start;
    gap: 32px;
  }

  .page-about .about-start__aside {
    margin-top: 56px;
  }

  .page-about .about-lines__stack {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: 20px;
    align-items: start;
  }

  .page-about .line-card--a {
    grid-column: 1 / span 4;
  }

  .page-about .line-card--b {
    grid-column: 5 / span 4;
    margin-top: 44px;
  }

  .page-about .line-card--c {
    grid-column: 9 / span 4;
    margin-top: 88px;
  }

  .page-about .about-tl {
    display: flex;
    gap: 0;
    border-top: var(--about-hair);
    padding-top: 0;
    align-items: flex-start;
  }

  .page-about .about-tl__node {
    flex: 1 1 0;
    min-width: 0;
    border-top: 0;
    border-bottom: 0;
    padding-top: 26px;
    padding-right: 16px;
  }

  .page-about .about-tl__head {
    display: block;
    padding: 0 0 12px;
    position: relative;
  }

  .page-about .about-tl__dot {
    position: absolute;
    top: -31px;
    left: 0;
  }

  .page-about .about-tl__code {
    display: block;
    margin-bottom: 6px;
  }

  .page-about .about-tl__phase {
    display: block;
  }

  .page-about .about-tl__body {
    padding: 0 0 10px;
  }

  .page-about .about-tl__node[open] .about-tl__dot {
    box-shadow: 0 0 0 3px rgba(255, 106, 43, 0.22);
  }

  .page-about .about-team__figure {
    margin-top: 30px;
  }

  .page-about .about-source__figure {
    margin-top: 6px;
  }

  .page-about .about-milestone__intro {
    position: sticky;
    top: calc(var(--pb-header-h) + 24px);
  }

  .page-about .about-closing {
    grid-template-columns: 1fr auto;
    align-items: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .line-card,
  .page-about .line-card::before,
  .page-about .about-tl__dot {
    transition: none;
  }
}
<<<END>>>