.page-about {
  --rail-w: 208px;
  --about-line: 1px solid var(--line-soft);
  color: var(--paper);
  font-family: var(--font-display);
  background:
    radial-gradient(900px 420px at 86% -6%, rgba(200, 255, 61, 0.10), transparent 62%),
    linear-gradient(180deg, var(--ink-0) 0%, var(--ink-1) 48%, var(--ink-0) 100%);
  padding-bottom: clamp(44px, 7vw, 96px);
}

/* ---------- 首屏 ---------- */
.page-about .history-hero {
  padding: clamp(20px, 4vw, 38px) 0 clamp(34px, 5vw, 64px);
  border-bottom: var(--about-line);
}

.page-about .breadcrumb {
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.page-about .breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin-right: 8px;
  color: var(--line-soft);
}

.page-about .breadcrumb-link {
  color: var(--lime);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease;
}

.page-about .breadcrumb-link:hover,
.page-about .breadcrumb-link:focus-visible {
  border-bottom-color: var(--lime);
}

.page-about .history-hero__grid {
  display: grid;
  gap: clamp(26px, 4vw, 44px);
  margin-top: clamp(10px, 2vw, 20px);
}

.page-about .history-hero__title {
  font-family: var(--font-display);
  font-size: clamp(2.1rem, 7.2vw, 4.3rem);
  font-weight: 800;
  line-height: 1.03;
  letter-spacing: -0.035em;
  margin: 0.22em 0 0.34em;
}

.page-about .history-hero .lede {
  max-width: 54ch;
  font-size: var(--step-1);
  line-height: 1.85;
  color: rgba(243, 246, 238, 0.84);
  margin: 0;
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(18px, 3vw, 28px);
}

.page-about .hero-stats {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .hero-stat {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 12px 14px;
  border-radius: var(--radius-m);
  background: rgba(30, 59, 49, 0.55);
  border-left: 3px solid var(--lime);
}

.page-about .hero-stat:nth-child(3) {
  border-left-color: var(--lime-soft);
}

.page-about .hero-stat:nth-child(4) {
  border-left-color: var(--muted);
}

.page-about .hero-stat__num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 4.4vw, 2rem);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--lime);
}

.page-about .hero-stat__label {
  font-size: 0.875rem;
  line-height: 1.5;
  color: var(--muted);
}

/* ---------- 阶梯目录与正文长卷 ---------- */
.page-about .history-body {
  display: grid;
  gap: clamp(26px, 4vw, 34px);
  padding-top: clamp(30px, 5vw, 64px);
}

.page-about .history-rail {
  border-bottom: var(--about-line);
  padding-bottom: 12px;
}

.page-about .history-rail__label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .rail-list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

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

.page-about .rail-step {
  flex: 0 0 auto;
}

.page-about .rail-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line-soft);
  background: rgba(14, 42, 34, 0.7);
  color: var(--paper);
  text-decoration: none;
  font-size: 0.8125rem;
  white-space: nowrap;
  transition: border-color 0.2s ease, color 0.2s ease, background-color 0.2s ease;
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  border-color: var(--lime);
  color: var(--lime);
}

.page-about .rail-link__idx {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  color: var(--lime);
}

.page-about .history-flow {
  min-width: 0;
}

.page-about .chapter {
  padding: clamp(26px, 4vw, 44px) 0;
  border-top: var(--about-line);
  scroll-margin-top: 92px;
}

.page-about .chapter-head {
  display: flex;
  align-items: center;
  gap: clamp(10px, 2vw, 20px);
  padding: clamp(12px, 2vw, 20px) clamp(14px, 2.4vw, 26px);
  border-radius: var(--radius-m);
  border-left: 4px solid var(--lime);
  background: linear-gradient(90deg, rgba(30, 59, 49, 0.95), rgba(30, 59, 49, 0.4));
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .chapter-num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: clamp(1.9rem, 5.6vw, 3.1rem);
  font-weight: 700;
  line-height: 0.82;
  letter-spacing: -0.05em;
  color: rgba(200, 255, 61, 0.14);
  -webkit-text-stroke: 1.4px var(--lime);
}

.page-about .chapter p {
  max-width: 62ch;
  margin: 0 0 1em;
  font-size: var(--step-0);
  line-height: 1.9;
  color: rgba(243, 246, 238, 0.84);
}

.page-about .chapter-kicker {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--lime);
  line-height: 1.4;
}

.page-about .chapter-title {
  margin: 0;
  font-size: clamp(1.35rem, 3.2vw, 1.9rem);
  line-height: 1.28;
  letter-spacing: -0.015em;
}

.page-about .accent {
  color: var(--lime);
  font-weight: 600;
}

/* 手卡注释 */
.page-about .note-card {
  max-width: 56ch;
  margin: clamp(16px, 3vw, 26px) 0 0;
  padding: 14px 18px;
  border-radius: var(--radius-m);
  border: 1px solid var(--line-lime);
  background: rgba(30, 59, 49, 0.66);
}

.page-about .note-card > summary {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--lime);
}

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

.page-about .note-card > summary::after {
  content: "+";
  margin-left: auto;
  font-size: 1rem;
}

.page-about .note-card[open] > summary::after {
  content: "−";
}

.page-about .note-card p {
  margin: 12px 0 0;
  max-width: none;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: rgba(243, 246, 238, 0.8);
}

/* 图 */
.page-about .figure {
  margin: clamp(20px, 3vw, 32px) 0 0;
}

.page-about .figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-m);
  object-fit: cover;
  border: 1px solid var(--line-lime);
}

.page-about .figure--portrait img {
  max-width: 360px;
  border-radius: var(--radius-l);
}

.page-about .figure .media-caption {
  margin-top: 10px;
  max-width: 52ch;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  line-height: 1.6;
  letter-spacing: 0.06em;
  color: var(--muted);
}

/* 三类内容 */
.page-about .topic-grid {
  display: grid;
  gap: 12px;
  margin: clamp(18px, 3vw, 28px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .topic {
  padding: 18px;
  border-radius: var(--radius-m);
  background: rgba(30, 59, 49, 0.72);
  border-top: 3px solid var(--lime);
}

.page-about .topic:nth-child(2) {
  border-top-color: var(--lime-soft);
}

.page-about .topic:nth-child(3) {
  border-top-color: var(--muted);
}

.page-about .topic h3 {
  margin: 0 0 8px;
  font-size: 1.0625rem;
  letter-spacing: -0.01em;
}

.page-about .topic p {
  margin: 0;
  max-width: none;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: rgba(243, 246, 238, 0.78);
}

/* 四个小组 */
.page-about .crew-grid {
  display: grid;
  gap: 12px;
  margin: clamp(18px, 3vw, 28px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .crew {
  padding: 16px 18px;
  border-radius: var(--radius-m);
  background: rgba(17, 20, 19, 0.7);
  border-left: 3px solid var(--lime);
}

.page-about .crew:nth-child(2) {
  border-left-color: var(--lime-soft);
}

.page-about .crew:nth-child(3) {
  border-left-color: var(--muted);
}

.page-about .crew:nth-child(4) {
  border-left-color: var(--alert);
}

.page-about .crew h3 {
  margin: 0 0 6px;
  font-size: 0.9875rem;
  letter-spacing: -0.01em;
}

.page-about .crew p {
  margin: 0;
  max-width: none;
  font-size: 0.875rem;
  line-height: 1.75;
  color: rgba(243, 246, 238, 0.76);
}

/* 里程碑 */
.page-about .milestone-wrap {
  margin-top: clamp(18px, 3vw, 28px);
}

.page-about .milestone-line {
  display: block;
  width: 100%;
  height: 14px;
  margin-bottom: 8px;
}

.page-about .milestone-strip {
  display: flex;
  gap: 12px;
  margin: 0;
  padding: 0 2px 14px;
  list-style: none;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  scrollbar-width: thin;
}

.page-about .milestone {
  flex: 0 0 min(240px, 76vw);
  scroll-snap-align: start;
  padding: 16px 16px 18px;
  border-radius: var(--radius-m);
  background: rgba(17, 20, 19, 0.86);
  border: 1px solid var(--line-soft);
}

.page-about .milestone h3 {
  margin: 10px 0 6px;
  font-size: 1rem;
  letter-spacing: -0.01em;
}

.page-about .milestone p {
  margin: 0;
  max-width: none;
  font-size: 0.875rem;
  line-height: 1.75;
  color: rgba(243, 246, 238, 0.76);
}

/* 三个理由 */
.page-about .reason-list {
  display: grid;
  gap: 12px;
  margin: clamp(18px, 3vw, 28px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .reason {
  padding: 22px 18px 20px;
  border-radius: var(--radius-m);
  border: 1px solid var(--line-lime);
  background: linear-gradient(160deg, rgba(30, 59, 49, 0.95), rgba(14, 42, 34, 0.5));
}

.page-about .reason__idx {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--lime);
}

.page-about .reason h3 {
  margin: 0 0 8px;
  font-size: 1.0625rem;
  letter-spacing: -0.01em;
}

.page-about .reason p {
  margin: 0;
  max-width: none;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: rgba(243, 246, 238, 0.8);
}

/* 收尾 */
.page-about .history-cta {
  margin-top: clamp(28px, 5vw, 56px);
  padding: clamp(24px, 4vw, 42px);
  border-radius: var(--radius-l);
  border: 1px solid var(--line-lime);
  background:
    radial-gradient(420px 220px at 88% 10%, rgba(200, 255, 61, 0.18), transparent 70%),
    var(--ink-3);
}

.page-about .history-cta h2 {
  margin: 0 0 10px;
  font-size: clamp(1.4rem, 3.4vw, 2rem);
  line-height: 1.25;
  letter-spacing: -0.02em;
}

.page-about .history-cta p {
  max-width: 56ch;
  margin: 0 0 20px;
  font-size: var(--step-0);
  line-height: 1.85;
  color: rgba(243, 246, 238, 0.84);
}

.page-about .cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .to-top {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 18px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.page-about .to-top:hover,
.page-about .to-top:focus-visible {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

/* ---------- 窄屏适配 ---------- */
@media (max-width: 420px) {
  .page-about .hero-stat {
    flex-wrap: wrap;
    gap: 4px 10px;
  }

  .page-about .chapter-head {
    align-items: flex-start;
  }
}

/* ---------- 平板及桌面 ---------- */
@media (min-width: 720px) {
  .page-about .topic-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .figure--portrait img {
    max-width: 420px;
  }
}

@media (min-width: 940px) {
  .page-about .history-hero__grid {
    grid-template-columns: minmax(0, 1.3fr) minmax(260px, 0.7fr);
    align-items: end;
    gap: clamp(32px, 5vw, 72px);
  }

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

@media (min-width: 1000px) {
  .page-about .history-body {
    grid-template-columns: var(--rail-w) minmax(0, 1fr);
    gap: clamp(32px, 4vw, 60px);
    align-items: start;
  }

  .page-about .history-rail {
    position: sticky;
    top: 96px;
    border-bottom: 0;
    padding-bottom: 0;
  }

  .page-about .rail-list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
  }

  .page-about .rail-step {
    width: 100%;
  }

  .page-about .rail-link {
    width: 100%;
    padding: 10px 12px;
    border-radius: var(--radius-s);
    border-color: transparent;
    border-left: 2px solid var(--line-soft);
    background: transparent;
    white-space: normal;
    text-align: left;
  }

  .page-about .rail-step:nth-child(2) .rail-link {
    margin-left: 8px;
    width: calc(100% - 8px);
  }

  .page-about .rail-step:nth-child(3) .rail-link {
    margin-left: 16px;
    width: calc(100% - 16px);
  }

  .page-about .rail-step:nth-child(4) .rail-link {
    margin-left: 24px;
    width: calc(100% - 24px);
  }

  .page-about .rail-step:nth-child(5) .rail-link {
    margin-left: 32px;
    width: calc(100% - 32px);
  }

  .page-about .rail-link:hover,
  .page-about .rail-link:focus-visible {
    border-left-color: var(--lime);
    background: rgba(200, 255, 61, 0.07);
  }
}

/* ---------- 偏好与打印 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media print {
  .page-about {
    background: #ffffff;
    color: #111413;
    padding-bottom: 0;
  }

  .page-about .history-rail,
  .page-about .to-top,
  .page-about .cta-actions {
    display: none;
  }

  .page-about .chapter,
  .page-about .history-cta,
  .page-about .milestone,
  .page-about .reason,
  .page-about .topic,
  .page-about .crew {
    break-inside: avoid;
    border-color: #c7d3c7;
    background: #ffffff;
  }

  .page-about .chapter p,
  .page-about .reason p,
  .page-about .topic p,
  .page-about .crew p,
  .page-about .milestone p,
  .page-about .history-cta p {
    color: #26302a;
  }

  .page-about .milestone-strip {
    flex-wrap: wrap;
    overflow: visible;
  }
}
<<<END>>>