.page-about {
  --ab-rail: 104px;
  color: var(--paper);
  padding-bottom: clamp(56px, 8vw, 112px);
}

.page-about .breadcrumb {
  padding-top: calc(var(--header-h) + 28px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 32px;
  padding: clamp(26px, 4vw, 44px) 0 clamp(40px, 6vw, 76px);
}

.page-about .hero-copy h1 {
  font-size: var(--fs-display);
  font-weight: 800;
  line-height: 1.06;
  letter-spacing: -0.02em;
  margin: 12px 0 20px;
  max-width: 18ch;
}

.page-about .hero-lede {
  font-size: var(--fs-body);
  line-height: 1.78;
  color: var(--paper-86);
  max-width: 56ch;
  margin: 0 0 28px;
}

.page-about .hero-index {
  border-top: 1px solid var(--line-soft);
  padding-top: 16px;
}

.page-about .hero-index-title {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--steel);
  margin: 0 0 12px;
}

.page-about .hero-index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
}

.page-about .hero-index-list a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 8px 0;
  font-size: 14px;
  color: var(--paper-86);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.page-about .hero-index-list a span {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--steel);
  transition: color 0.16s var(--ease);
}

.page-about .hero-index-list a:hover,
.page-about .hero-index-list a:focus-visible {
  color: var(--orange);
  border-bottom-color: var(--hair);
}

.page-about .hero-index-list a:hover span,
.page-about .hero-index-list a:focus-visible span {
  color: var(--orange-soft);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  display: grid;
  gap: 18px;
  padding: clamp(44px, 6vw, 88px) 0;
  border-top: 1px solid var(--hair);
}

.page-about .ch-rail {
  display: flex;
  align-items: center;
  gap: 16px;
}

.page-about .ch-num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(34px, 7vw, 66px);
  line-height: 0.9;
  letter-spacing: -0.03em;
  color: var(--paper);
  opacity: 0.18;
}

.page-about .ch-year {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--steel);
  white-space: nowrap;
}

.page-about .ch-body h2 {
  font-size: var(--fs-section);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.01em;
  margin: 0 0 18px;
  max-width: 20ch;
}

.page-about .ch-body p {
  font-size: var(--fs-body);
  line-height: 1.78;
  color: var(--paper-86);
  margin: 0 0 14px;
  max-width: 62ch;
}

.page-about .dropcap::first-letter {
  float: left;
  font-weight: 800;
  font-size: 3.2em;
  line-height: 0.84;
  padding: 8px 12px 0 0;
  color: var(--orange);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0 0 26px;
  border: 1px solid var(--hair);
  background: linear-gradient(158deg, var(--ink-2), var(--night));
  overflow: hidden;
}

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

.page-about .about-figure figcaption {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--steel);
  padding: 10px 14px;
  border-top: 1px solid var(--hair);
}

.page-about .about-figure--shade {
  margin-top: 6px;
  margin-bottom: 0;
  border-bottom: 0;
}

.page-about .about-figure--shade img {
  opacity: 0.5;
}

.page-about .about-figure--side {
  margin-bottom: 14px;
}

/* ---------- 时间线 ---------- */
.page-about .timeline {
  margin: 30px 0 0;
  padding-left: 22px;
  border-left: 1px solid var(--line-soft);
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 22px;
}

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

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 6px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--grass);
  transition: background 0.16s var(--ease), box-shadow 0.16s var(--ease);
}

.page-about .tl-item:hover::before {
  background: var(--orange);
  box-shadow: 0 0 0 4px rgba(255, 106, 43, 0.16);
}

.page-about .tl-when {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--paper);
  margin: 0 0 4px;
  transition: color 0.16s var(--ease);
}

.page-about .tl-item:hover .tl-when {
  color: var(--orange);
}

.page-about .tl-what {
  font-size: 16px;
  line-height: 1.7;
  color: var(--paper-86);
  margin: 0 0 4px;
  max-width: 52ch;
}

.page-about .tl-kpi {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--steel);
  margin: 0;
  opacity: 0.6;
  transition: opacity 0.16s var(--ease), color 0.16s var(--ease);
}

.page-about .tl-item:hover .tl-kpi {
  opacity: 1;
  color: var(--orange-soft);
}

/* ---------- 流程 ---------- */
.page-about .flow-list {
  list-style: none;
  margin: 22px 0 18px;
  padding: 0;
}

.page-about .flow-item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 14px;
  padding: 16px 0;
  border-top: 1px solid var(--hair);
}

.page-about .flow-item:last-child {
  border-bottom: 1px solid var(--hair);
}

.page-about .flow-step {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--orange);
  padding-top: 3px;
}

.page-about .flow-body strong {
  display: block;
  font-size: var(--fs-sub);
  font-weight: 700;
  color: var(--paper);
  margin-bottom: 4px;
}

.page-about .flow-body p {
  margin: 0;
  font-size: 16px;
  max-width: none;
}

/* ---------- 分工 ---------- */
.page-about .team-list {
  margin: 22px 0 20px;
}

.page-about .team-row {
  padding: 18px 0 18px 18px;
  border-left: 2px solid var(--line-soft);
  transition: border-color 0.16s var(--ease);
}

.page-about .team-row + .team-row {
  margin-top: 4px;
}

.page-about .team-row:hover {
  border-left-color: var(--orange);
}

.page-about .team-head {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin: 0 0 6px;
}

.page-about .team-count {
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--paper);
}

.page-about .team-name {
  font-size: var(--fs-sub);
  font-weight: 700;
  color: var(--paper);
  letter-spacing: 0.01em;
}

.page-about .team-desc {
  margin: 0;
  font-size: 16px;
  line-height: 1.72;
  color: var(--paper-86);
  max-width: 58ch;
}

/* ---------- 版本演进 ---------- */
.page-about .ver-stack {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 6px;
  margin: 0 0 20px;
  padding: 20px 0;
}

.page-about .ver-bar {
  height: 36px;
  display: flex;
  align-items: center;
  padding: 0 12px;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--paper);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 100%;
}

.page-about .ver-bar--1 {
  width: 100%;
  background: var(--ink-3);
  border: 1px solid var(--line-soft);
  color: var(--steel);
}

.page-about .ver-bar--2 {
  width: 78%;
  background: rgba(46, 107, 80, 0.5);
}

.page-about .ver-bar--3 {
  width: 56%;
  background: var(--orange);
  color: var(--ink);
  font-weight: 700;
}

.page-about .ver-notes {
  border-top: 1px solid var(--hair);
}

.page-about .ver-note {
  border-bottom: 1px solid var(--hair);
}

.page-about .ver-note summary {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 13px 0;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--steel);
  list-style: none;
  transition: color 0.16s var(--ease);
}

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

.page-about .ver-note summary::before {
  content: "+";
  color: var(--orange);
  font-weight: 700;
}

.page-about .ver-note[open] summary {
  color: var(--paper);
}

.page-about .ver-note[open] summary::before {
  content: "–";
}

.page-about .ver-note summary:hover {
  color: var(--orange-soft);
}

.page-about .ver-note p {
  margin: 0 0 14px;
  padding-left: 22px;
  font-size: 15px;
  line-height: 1.72;
  color: var(--paper-86);
  max-width: 56ch;
}

/* ---------- 结尾链接 ---------- */
.page-about .ch-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.page-about .ch-links .btn {
  text-decoration: none;
}

/* ---------- 桌面 ---------- */
@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 8fr) minmax(0, 3fr);
    gap: clamp(32px, 5vw, 72px);
    align-items: end;
  }

  .page-about .hero-index {
    padding-top: 18px;
  }

  .page-about .about-chapter {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 0 clamp(24px, 3.5vw, 56px);
  }

  .page-about .ch-rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 22px;
  }

  .page-about .ch-year {
    writing-mode: vertical-rl;
    letter-spacing: 0.22em;
    padding-top: 4px;
  }

  .page-about .about-chapter--narrow .ch-body {
    max-width: 60ch;
    margin-left: auto;
  }

  .page-about .ch-split {
    display: grid;
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: clamp(24px, 4vw, 48px);
    align-items: start;
  }

  .page-about .about-figure--side {
    margin-top: 26px;
    margin-bottom: 0;
    position: sticky;
    top: calc(var(--header-h) + 24px);
  }

  .page-about .team-row {
    display: grid;
    grid-template-columns: 170px minmax(0, 1fr);
    gap: 0 20px;
    align-items: baseline;
  }

  .page-about .team-head {
    margin-bottom: 0;
  }

  .page-about .ver-bar {
    height: 40px;
    font-size: 12px;
  }
}

@media (min-width: 1180px) {
  .page-about .ch-body h2 {
    max-width: 22ch;
  }
}
<<<END>>>