.page-about {
  --about-rail: 78px;
  --about-line: rgba(216, 163, 64, .42);
  --about-ink-soft: rgba(24, 34, 43, .74);
  --about-paper-soft: rgba(247, 241, 228, .8);
  background: var(--paper);
  color: var(--ink);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(20px, 4vw, 34px) 0 clamp(42px, 7vw, 74px);
  background:
    radial-gradient(120% 92% at 102% 0%, rgba(18, 78, 90, .88) 0%, rgba(12, 42, 68, 0) 60%),
    linear-gradient(168deg, var(--deep) 0%, var(--deep-2) 72%);
  color: var(--paper);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -110px;
  bottom: -160px;
  width: 340px;
  height: 340px;
  border-radius: 46% 54% 62% 38% / 52% 40% 60% 48%;
  background: rgba(216, 163, 64, .13);
  pointer-events: none;
}

.page-about .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  list-style: none;
  margin: 0 0 clamp(22px, 4vw, 34px);
  padding: 0;
  font-size: 14px;
}

.page-about .breadcrumb li {
  display: flex;
  align-items: center;
  gap: 8px;
  color: rgba(247, 241, 228, .6);
}

.page-about .breadcrumb li + li::before {
  content: "/";
  color: rgba(216, 163, 64, .65);
}

.page-about .breadcrumb a {
  color: rgba(247, 241, 228, .8);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color .2s ease, color .2s ease;
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--sand);
}

.page-about .breadcrumb [aria-current="page"] {
  color: var(--paper);
}

.page-about .hero-grid {
  display: grid;
  gap: clamp(26px, 4vw, 44px);
  position: relative;
  z-index: 1;
}

.page-about .hero-copy .eyebrow {
  margin: 0;
  color: var(--sand);
  font-size: 13px;
  letter-spacing: .18em;
  font-weight: 700;
}

.page-about .hero-copy h1 {
  margin: 14px 0 18px;
  font-size: clamp(30px, 5.4vw, 52px);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: .01em;
  max-width: 15em;
}

.page-about .hero-copy .lead {
  margin: 0;
  font-size: clamp(15px, 1.9vw, 17px);
  line-height: 1.85;
  color: var(--about-paper-soft);
  max-width: 34em;
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(24px, 3vw, 32px);
}

.page-about .hero-index {
  border: 1px solid rgba(216, 163, 64, .34);
  border-radius: 4px 22px 22px 22px;
  background: rgba(247, 241, 228, .055);
  padding: 18px 18px 14px;
}

.page-about .hero-index-title {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: .24em;
  color: rgba(216, 163, 64, .92);
}

.page-about .hero-index ol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .hero-index a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 9px 8px 9px 11px;
  font-size: 14px;
  color: rgba(247, 241, 228, .86);
  text-decoration: none;
  border-left: 2px solid transparent;
  border-radius: 0 9px 9px 0;
  transition: background .2s ease, border-color .2s ease, color .2s ease;
}

.page-about .hero-index a:hover,
.page-about .hero-index a:focus-visible {
  border-left-color: var(--coral);
  background: rgba(242, 107, 74, .12);
  color: var(--paper);
}

.page-about .hero-index .mono {
  color: var(--sand);
  font-size: 12px;
  letter-spacing: .06em;
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  display: grid;
  gap: 14px;
}

.page-about .chapter-index {
  margin: 0;
  font-size: 13px;
  letter-spacing: .2em;
  color: var(--sand);
  font-weight: 700;
}

.page-about .chapter-body h2 {
  margin: 0 0 18px;
  font-size: clamp(24px, 3.3vw, 34px);
  font-weight: 800;
  line-height: 1.26;
  letter-spacing: .02em;
  max-width: 20em;
}

.page-about .chapter-body > p {
  margin: 0 0 16px;
  line-height: 1.85;
  color: var(--about-ink-soft);
  max-width: 42em;
}

/* ---------- 为什么 ---------- */
.page-about .why-grid {
  display: grid;
  gap: clamp(22px, 4vw, 36px);
  margin: clamp(20px, 3vw, 30px) 0 clamp(26px, 4vw, 36px);
  align-items: start;
}

.page-about .why-copy p {
  margin: 0 0 16px;
  line-height: 1.85;
  color: var(--about-ink-soft);
  max-width: 36em;
}

.page-about .mark {
  background: linear-gradient(180deg, transparent 62%, rgba(216, 163, 64, .42) 62%, rgba(216, 163, 64, .42) 92%, transparent 92%);
  padding: 0 2px;
  color: var(--ink);
  font-weight: 600;
}

.page-about .about-figure {
  margin: 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: 22px 22px 22px 62px;
  border: 1px solid var(--line-sand);
  background: var(--sand-soft);
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
  max-width: 30em;
}

/* ---------- 折叠卡片 ---------- */
.page-about .promise-grid {
  display: grid;
  gap: 12px;
  margin: 0;
}

.page-about .promise {
  border: 1px solid var(--line-ink);
  border-radius: 4px 16px 16px 16px;
  background: var(--paper-2);
  transition: border-color .2s ease, box-shadow .2s ease;
}

.page-about .promise[open] {
  border-color: var(--line-sand);
  box-shadow: var(--shadow);
}

.page-about .promise summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 15px 17px;
  cursor: pointer;
  list-style: none;
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

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

.page-about .promise summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--coral);
}

.page-about .promise[open] summary::after {
  content: "–";
}

.page-about .promise summary:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: 2px;
}

.page-about .p-index {
  flex: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 26px;
  padding: 3px 6px;
  border-radius: 6px;
  font-size: 12px;
  background: var(--sand-soft);
  color: var(--wine);
}

.page-about .promise:nth-child(2) .p-index {
  background: rgba(18, 78, 90, .14);
  color: var(--teal);
}

.page-about .promise:nth-child(3) .p-index {
  background: rgba(58, 49, 93, .14);
  color: var(--indigo);
}

.page-about .promise:nth-child(4) .p-index {
  background: rgba(115, 46, 60, .14);
  color: var(--wine);
}

.page-about .promise-body {
  padding: 0 17px 16px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-ink-soft);
}

/* ---------- 协同 ---------- */
.page-about .about-routes {
  position: relative;
  padding: clamp(44px, 6vw, 78px) 0;
  color: var(--paper);
  background:
    linear-gradient(148deg, var(--teal) 0%, #0f4450 52%, var(--deep) 100%);
  overflow: hidden;
}

.page-about .about-routes::before {
  content: "";
  position: absolute;
  left: -120px;
  top: -140px;
  width: 300px;
  height: 300px;
  border-radius: 54% 46% 38% 62% / 44% 58% 42% 56%;
  background: rgba(216, 163, 64, .1);
  pointer-events: none;
}

.page-about .about-routes .wrap {
  position: relative;
  z-index: 1;
}

.page-about .on-dark h2,
.page-about .on-dark h3 {
  color: var(--paper);
}

.page-about .on-dark .chapter-body > p {
  color: var(--about-paper-soft);
}

.page-about .route-lead {
  max-width: 40em;
}

.page-about .route-flow {
  list-style: none;
  margin: clamp(24px, 4vw, 34px) 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .route-step {
  position: relative;
  padding: 20px 18px 18px;
  border: 1px solid rgba(247, 241, 228, .2);
  border-radius: 4px 18px 18px 18px;
  background: rgba(247, 241, 228, .06);
}

.page-about .route-num {
  display: inline-block;
  margin-bottom: 8px;
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--sand);
  border-bottom: 1px solid rgba(216, 163, 64, .5);
  padding-bottom: 3px;
}

.page-about .route-step h3 {
  margin: 0 0 8px;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: .02em;
}

.page-about .route-step p {
  margin: 0 0 14px;
  font-size: 14.5px;
  line-height: 1.78;
  color: rgba(247, 241, 228, .78);
}

.page-about .route-link {
  display: inline-block;
  font-size: 14px;
  color: var(--sand);
  text-decoration: none;
  border-bottom: 1px solid rgba(216, 163, 64, .5);
  padding-bottom: 2px;
  transition: color .2s ease, border-color .2s ease;
}

.page-about .route-link::after {
  content: " →";
  font-family: var(--font-mono);
}

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

.page-about .route-note {
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding-top: 16px;
  border-top: 1px solid rgba(216, 163, 64, .3);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--about-paper-soft);
  max-width: 44em;
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  gap: clamp(22px, 4vw, 36px);
  margin-top: clamp(20px, 3vw, 28px);
  align-items: start;
}

.page-about .team-roles {
  margin: 0 0 18px;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .team-role {
  display: grid;
  gap: 4px;
  padding: 14px 16px;
  border-left: 3px solid var(--sand);
  background: var(--paper-2);
  border-radius: 0 12px 12px 0;
}

.page-about .team-role dt {
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: .02em;
}

.page-about .team-role dd {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--about-ink-soft);
}

.page-about .team-copy > p {
  margin: 0;
  line-height: 1.85;
  color: var(--about-ink-soft);
  max-width: 38em;
}

/* ---------- 阶段 ---------- */
.page-about .about-stages {
  position: relative;
  padding: clamp(46px, 6vw, 82px) 0;
  color: var(--paper);
  background: linear-gradient(150deg, var(--indigo) 0%, #2b2453 54%, var(--deep) 100%);
  overflow: hidden;
}

.page-about .stage-bg {
  position: absolute;
  inset: 0;
  margin: 0;
  pointer-events: none;
}

.page-about .stage-bg img {
  width: 100%;
  max-width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: .15;
  mix-blend-mode: screen;
}

.page-about .about-stages .wrap {
  position: relative;
  z-index: 1;
}

.page-about .about-stages .chapter-index {
  color: var(--sand);
}

.page-about .stage-scroll {
  margin-top: clamp(24px, 4vw, 34px);
  overflow-x: auto;
  padding-bottom: 12px;
  scrollbar-width: thin;
  scrollbar-color: rgba(216, 163, 64, .55) transparent;
}

.page-about .stage-scroll::-webkit-scrollbar {
  height: 6px;
}

.page-about .stage-scroll::-webkit-scrollbar-thumb {
  background: rgba(216, 163, 64, .5);
  border-radius: 999px;
}

.page-about .stage-track {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(196px, 1fr);
  gap: 16px;
  min-width: 100%;
}

.page-about .stage {
  position: relative;
  padding: 24px 2px 4px;
  border-top: 1px solid rgba(216, 163, 64, .42);
}

.page-about .stage::before {
  content: "";
  position: absolute;
  top: -5px;
  left: 0;
  width: 9px;
  height: 9px;
  background: var(--sand);
  transform: rotate(45deg);
}

.page-about .stage:first-child::before {
  background: var(--coral);
}

.page-about .stage-year {
  display: block;
  font-size: 13px;
  letter-spacing: .16em;
  color: var(--sand);
  margin-bottom: 6px;
}

.page-about .stage-title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: .02em;
  line-height: 1.4;
}

.page-about .stage-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: rgba(247, 241, 228, .78);
}

/* ---------- 覆盖 ---------- */
.page-about .reach-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: clamp(22px, 3vw, 30px) 0 clamp(22px, 3vw, 28px);
}

.page-about .reach-item {
  display: grid;
  gap: 6px;
  padding: 16px 15px;
  border-radius: 4px 14px 14px 14px;
  background: var(--sand-soft);
  border-left: 3px solid var(--deep);
}

.page-about .reach-num {
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1.05;
  font-weight: 700;
  color: var(--deep);
  letter-spacing: .01em;
}

.page-about .reach-num em {
  font-style: normal;
  font-size: .6em;
  color: var(--coral);
  margin-left: 1px;
}

.page-about .reach-label {
  font-size: 13.5px;
  line-height: 1.6;
  color: rgba(24, 34, 43, .78);
}

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

.page-about .reach-list li {
  position: relative;
  padding-left: 22px;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--about-ink-soft);
  max-width: 40em;
}

.page-about .reach-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 12px;
  height: 2px;
  background: var(--coral);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  padding: 0 0 clamp(48px, 7vw, 84px);
}

.page-about .cta-panel {
  display: grid;
  gap: 22px;
  padding: clamp(24px, 4vw, 38px);
  border-radius: 4px 26px 26px 26px;
  background:
    radial-gradient(110% 120% at 100% 0%, rgba(18, 78, 90, .95) 0%, rgba(12, 42, 68, 0) 62%),
    var(--deep);
  color: var(--paper);
  align-items: center;
}

.page-about .cta-copy .eyebrow {
  margin: 0 0 10px;
  color: var(--sand);
  font-size: 12px;
  letter-spacing: .2em;
  font-weight: 700;
}

.page-about .cta-copy h2 {
  margin: 0 0 12px;
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: .02em;
}

.page-about .cta-copy p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-paper-soft);
  max-width: 36em;
}

.page-about .cta-panel .btn {
  justify-self: start;
}

/* ---------- 断点 ---------- */
@media (min-width: 700px) {
  .page-about .promise-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .reach-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 860px) {
  .page-about .chapter {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    column-gap: clamp(20px, 3vw, 40px);
  }

  .page-about .chapter-index {
    position: relative;
    padding-top: 8px;
  }

  .page-about .chapter-index::after {
    content: "";
    display: block;
    width: 1px;
    height: 100%;
    min-height: 48px;
    margin: 12px 0 0 9px;
    background: linear-gradient(180deg, var(--about-line), transparent 88%);
  }

  .page-about .about-stages .chapter-index::after {
    background: linear-gradient(180deg, rgba(216, 163, 64, .5), transparent 88%);
  }

  .page-about .why-grid,
  .page-about .team-grid {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, .98fr);
  }

  .page-about .why-figure,
  .page-about .team-figure {
    margin-top: 18px;
  }
}

@media (min-width: 900px) {
  .page-about .hero-grid {
    grid-template-columns: minmax(0, 1fr) 300px;
    align-items: end;
  }

  .page-about .route-flow {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .cta-panel {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 32px;
  }

  .page-about .cta-panel .btn {
    justify-self: end;
  }
}

@media (min-width: 1000px) {
  .page-about .stage-track {
    grid-auto-columns: minmax(0, 1fr);
    gap: 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}
<<<END>>>