.page-about {
  --about-pad: clamp(52px, 7vw, 104px);
  --about-tint: rgba(11, 31, 42, .55);
  background: var(--fog);
  color: var(--ink);
}

.page-about .breadcrumbs {
  margin-bottom: clamp(20px, 3vw, 34px);
}

/* ---------- Hero ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(32px, 5vw, 64px) 0 clamp(36px, 5vw, 64px);
  background: var(--ink);
  color: var(--mist);
  border-bottom: 1px solid var(--rule-dark);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(90deg, rgba(245, 247, 248, .05) 0 1px, transparent 1px 64px),
    repeating-linear-gradient(0deg, rgba(245, 247, 248, .05) 0 1px, transparent 1px 64px);
}

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

.page-about .hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 56px);
  align-items: end;
}

.page-about .hero-main h1 {
  margin: 12px 0 18px;
  font-size: clamp(34px, 6.4vw, 66px);
  line-height: 1.06;
  letter-spacing: -.02em;
  font-weight: 900;
  color: var(--mist);
}

.page-about .hero-lead {
  max-width: 60ch;
  margin: 0;
  font-size: clamp(15px, 1.3vw, 17px);
  line-height: 1.85;
  color: rgba(245, 247, 248, .78);
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 32px);
}

.page-about .hero-card {
  border: 1px solid var(--rule-dark);
  border-left: 3px solid var(--orange);
  background: var(--teal-900);
  padding: clamp(18px, 2.4vw, 26px);
}

.page-about .hero-card__k {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: rgba(245, 247, 248, .6);
}

.page-about .hero-card__v {
  margin: 6px 0 16px;
  font-family: var(--font-mono);
  font-size: clamp(34px, 5vw, 52px);
  line-height: 1;
  font-weight: 700;
  color: var(--orange);
}

.page-about .hero-card__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--rule-dark);
}

.page-about .hero-card__list li {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding: 9px 0;
  border-bottom: 1px solid var(--rule-dark-soft);
  font-size: 13px;
  color: rgba(245, 247, 248, .72);
}

.page-about .hero-card__list b {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--mist);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin: clamp(28px, 4vw, 48px) 0 0;
  border-top: 1px solid var(--rule-dark);
}

.page-about .hs-cell {
  padding: 16px 0;
  border-bottom: 1px solid var(--rule-dark-soft);
}

.page-about .hs-cell dt {
  font-size: 12.5px;
  line-height: 1.6;
  color: rgba(245, 247, 248, .58);
}

.page-about .hs-cell dd {
  margin: 6px 0 0;
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.page-about .hs-num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  color: var(--mist);
}

.page-about .hs-unit {
  font-size: 13px;
  color: var(--signal-soft);
}

/* ---------- 章节索引 ---------- */
.page-about .chapter-index {
  position: static;
  background: var(--mist);
  border-bottom: 1px solid var(--rule);
}

.page-about .chapter-index ol {
  display: flex;
  gap: 2px;
  margin: 0;
  padding: 0 var(--gutter);
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .chapter-index a {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 13px 12px;
  white-space: nowrap;
  font-size: 13.5px;
  color: var(--slate);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

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

.page-about .ci-num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--orange);
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  position: relative;
  padding: var(--about-pad) 0;
  background: var(--mist);
  border-top: 3px solid var(--accent, var(--teal-900));
}

.page-about .chapter--origin { --accent: var(--teal-900); background: var(--mist); }
.page-about .chapter--principles { --accent: var(--teal-700); }
.page-about .chapter--timeline { --accent: var(--indigo); background: var(--fog); }
.page-about .chapter--team { --accent: var(--teal-700); background: var(--mist); }
.page-about .chapter--partners { --accent: var(--wine); background: var(--fog); }
.page-about .chapter--diff { --accent: var(--indigo); background: var(--mist); }
.page-about .chapter--scale { --accent: var(--signal); }

.page-about .chapter--dark {
  background: var(--ink);
  color: var(--mist);
}

.page-about .chapter--scale {
  background: var(--teal-900);
}

.page-about .ch-head {
  max-width: 74ch;
}

.page-about .ch-num {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--accent, var(--teal-900));
}

.page-about .ch-head h2 {
  margin: 0 0 16px;
  font-size: clamp(25px, 3.4vw, 40px);
  line-height: 1.2;
  letter-spacing: -.02em;
  font-weight: 800;
  color: var(--ink);
}

.page-about .ch-lead {
  margin: 0;
  font-size: clamp(15px, 1.2vw, 16.5px);
  line-height: 1.9;
  color: var(--slate);
}

.page-about .chapter--dark .ch-num {
  color: var(--signal-soft);
}

.page-about .chapter--dark .ch-head h2 {
  color: var(--mist);
}

.page-about .chapter--dark .ch-lead {
  color: rgba(245, 247, 248, .74);
}

.page-about .chapter h3 {
  margin: 0 0 10px;
  font-size: clamp(17px, 1.8vw, 20px);
  font-weight: 800;
  letter-spacing: -.01em;
}

/* ---------- 媒体 ---------- */
.page-about .media {
  margin: 0;
  border: 1px solid var(--rule);
  background: var(--fog);
}

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

.page-about .media__label {
  display: block;
  padding: 9px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--slate);
  border-top: 1px solid var(--rule);
  background: var(--mist);
}

.page-about .origin-media {
  margin-top: clamp(28px, 4vw, 44px);
}

.page-about .origin-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(18px, 3vw, 34px);
  margin-top: clamp(26px, 3.5vw, 40px);
}

.page-about .origin-cols p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--slate);
}

/* ---------- 原则 ---------- */
.page-about .principle-list {
  list-style: none;
  margin: clamp(28px, 4vw, 48px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--rule-dark);
  border: 1px solid var(--rule-dark);
}

.page-about .principle {
  background: var(--ink);
  padding: clamp(20px, 2.6vw, 30px);
}

.page-about .principle__num {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--signal);
}

.page-about .principle h3 {
  color: var(--mist);
}

.page-about .principle p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(245, 247, 248, .74);
}

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  margin-top: clamp(28px, 4vw, 46px);
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 6px 22px;
  border-left: 1px solid var(--rule-strong);
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: -4.5px;
  top: 22px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent, var(--teal-900));
}

.page-about .tl-item:last-child {
  border-left-color: transparent;
}

.page-about .tl-sum {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 8px 14px;
  padding: 14px 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .tl-year {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--orange);
}

.page-about .tl-title {
  font-size: clamp(17px, 1.9vw, 21px);
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--ink);
}

.page-about .tl-mark {
  position: relative;
  flex: none;
  width: 13px;
  height: 13px;
  margin-left: auto;
  border: 1px solid var(--rule-strong);
}

.page-about .tl-mark::before,
.page-about .tl-mark::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  background: var(--slate);
  transform: translate(-50%, -50%);
}

.page-about .tl-mark::before { width: 7px; height: 1px; }
.page-about .tl-mark::after { width: 1px; height: 7px; transition: transform .2s var(--ease); }

.page-about details[open] > summary .tl-mark::after {
  transform: translate(-50%, -50%) scaleY(0);
}

.page-about .tl-body {
  padding: 0 0 18px;
  max-width: 68ch;
}

.page-about .tl-body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.9;
  color: var(--slate);
}

/* ---------- 团队 / 合作 ---------- */
.page-about .split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3.6vw, 48px);
  align-items: start;
}

.page-about .split__text p {
  margin: 0 0 16px;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--slate);
}

.page-about .split__text .ch-head {
  margin-bottom: 18px;
}

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

/* ---------- 变更说明 ---------- */
.page-about .diff-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  margin-top: clamp(26px, 3.6vw, 42px);
}

.page-about .diff-item {
  border: 1px solid var(--rule-strong);
  background: var(--mist);
  padding: 0 clamp(14px, 2vw, 22px);
}

.page-about .diff-sum {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px 14px;
  padding: 15px 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .diff-title {
  font-size: 15.5px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .diff-body {
  padding: 0 0 18px;
  max-width: 68ch;
}

.page-about .diff-body p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--slate);
}

.page-about .diff-foot {
  margin-top: clamp(26px, 3.4vw, 40px);
  padding-top: clamp(20px, 2.6vw, 30px);
  border-top: 1px solid var(--rule);
}

.page-about .diff-foot p {
  margin: 0 0 18px;
  max-width: 70ch;
  font-size: 15px;
  line-height: 1.9;
  color: var(--slate);
}

.page-about .diff-foot__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0;
}

/* ---------- 规模 ---------- */
.page-about .scale-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: clamp(28px, 4vw, 46px) 0 0;
  background: var(--rule-dark);
  border: 1px solid var(--rule-dark);
}

.page-about .scale-cell {
  background: var(--teal-900);
  padding: clamp(18px, 2.6vw, 28px);
}

.page-about .scale-cell dt {
  font-size: 12.5px;
  line-height: 1.6;
  color: rgba(245, 247, 248, .6);
}

.page-about .scale-cell dd {
  margin: 10px 0 0;
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.page-about .scale-num {
  font-family: var(--font-mono);
  font-size: clamp(32px, 4.6vw, 48px);
  line-height: 1;
  font-weight: 700;
  color: var(--mist);
}

.page-about .scale-unit {
  font-size: 13.5px;
  color: var(--signal-soft);
}

.page-about .scale-note {
  margin: clamp(22px, 3vw, 32px) 0 0;
  max-width: 70ch;
  font-size: 15px;
  line-height: 1.9;
  color: rgba(245, 247, 248, .74);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  padding: var(--about-pad) 0;
  background: var(--fog);
  border-top: 3px solid var(--orange);
}

.page-about .cta-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 40px);
  align-items: center;
  border: 1px solid var(--rule-strong);
  background: var(--mist);
  padding: clamp(22px, 3.4vw, 44px);
}

.page-about .cta-text h2 {
  margin: 8px 0 12px;
  font-size: clamp(22px, 2.8vw, 32px);
  line-height: 1.25;
  letter-spacing: -.02em;
  font-weight: 800;
  color: var(--ink);
}

.page-about .cta-text p {
  margin: 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.9;
  color: var(--slate);
}

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

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .hero-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    border-top: 1px solid var(--rule-dark);
  }

  .page-about .hs-cell {
    padding: 16px 18px 16px 0;
    border-bottom: 0;
  }

  .page-about .hs-cell + .hs-cell {
    padding-left: 18px;
    border-left: 1px solid var(--rule-dark-soft);
  }

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

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

@media (min-width: 900px) {
  .page-about .hero-grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, .85fr);
    gap: clamp(32px, 4vw, 64px);
  }

  .page-about .chapter-index {
    position: sticky;
    top: 0;
    z-index: 4;
  }

  .page-about .chapter-index ol {
    justify-content: flex-start;
    gap: 6px;
  }

  .page-about .origin-cols {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: clamp(24px, 4vw, 52px);
  }

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

  .page-about .split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
    gap: clamp(32px, 4.5vw, 64px);
  }

  .page-about .split--reverse {
    grid-template-columns: minmax(0, .95fr) minmax(0, 1.05fr);
  }

  .page-about .split--reverse .split__media {
    order: 0;
  }

  .page-about .cta-inner {
    grid-template-columns: minmax(0, 1.5fr) minmax(220px, .6fr);
    gap: clamp(24px, 4vw, 56px);
  }
}

@media (min-width: 1100px) {
  .page-about .ch-head h2 {
    max-width: 22ch;
  }
}
<<<END>>>