.page-about {
  --about-idx-w: 240px;
  position: relative;
  padding-block: 28px 88px;
}

.page-about .about-wrap {
  position: relative;
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  margin-bottom: 26px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

/* ---------- 首屏 ---------- */
.page-about .about-head {
  padding-bottom: 44px;
  border-bottom: 2px solid var(--line);
}

.page-about .about-eyebrow {
  margin: 0 0 20px;
  color: var(--ink-3);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.page-about .about-display {
  margin: 0;
  font-size: clamp(40px, 10.5vw, 118px);
  font-weight: 200;
  line-height: 0.98;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .about-display-a,
.page-about .about-display-b {
  display: block;
}

.page-about .about-display-b {
  background: var(--grad-seasons);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.page-about .about-lede {
  max-width: 62ch;
  margin: 30px 0 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink-2);
}

.page-about .about-facts {
  list-style: none;
  margin: 40px 0 0;
  padding: 2px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px;
  background: var(--line);
  border: 2px solid var(--line);
}

.page-about .about-facts li {
  background: var(--bg);
  padding: 18px 16px 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-fact-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 6vw, 34px);
  font-weight: 600;
  line-height: 1;
  color: var(--ink);
}

.page-about .about-facts li:nth-child(1) .about-fact-num { color: var(--spring); }
.page-about .about-facts li:nth-child(2) .about-fact-num { color: var(--winter); }
.page-about .about-facts li:nth-child(3) .about-fact-num { color: var(--summer); }
.page-about .about-facts li:nth-child(4) .about-fact-num { color: var(--autumn); }

.page-about .about-fact-label {
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--ink-2);
}

/* ---------- 主体网格 ---------- */
.page-about .about-body {
  margin-top: 56px;
  display: grid;
  gap: 40px;
}

/* ---------- 章节索引 ---------- */
.page-about .about-index-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.page-about .about-index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px;
  border: 2px solid var(--line);
  background: var(--line);
}

.page-about .about-index-link {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  align-items: baseline;
  gap: 8px;
  padding: 11px 10px;
  background: var(--bg);
  border-left: 2px solid transparent;
  text-decoration: none;
  color: var(--ink-2);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-index-link:hover,
.page-about .about-index-link:focus-visible {
  color: var(--ink);
  border-left-color: var(--winter);
  background: var(--panel);
}

.page-about .about-index-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ink-3);
}

.page-about .about-index-text {
  font-size: 13.5px;
  line-height: 1.45;
}

/* ---------- 章节通用 ---------- */
.page-about .about-flow {
  min-width: 0;
}

.page-about .about-section {
  position: relative;
  padding-block: 56px;
  border-top: 1px solid var(--line);
}

.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 8px;
}

.page-about .about-sec-num {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  font-size: clamp(26px, 7vw, 48px);
  line-height: 1;
  letter-spacing: -0.02em;
}

.page-about .about-section--focus .about-sec-num { color: var(--spring); }
.page-about .about-section--method .about-sec-num { color: var(--summer); }
.page-about .about-section--team .about-sec-num { color: var(--autumn); }
.page-about .about-section--timeline .about-sec-num { color: var(--winter); }
.page-about .about-section--partners .about-sec-num { color: var(--spring); }
.page-about .about-section--why .about-sec-num { color: var(--autumn); }

.page-about .about-sec-title {
  margin: 0 0 22px;
  font-size: clamp(25px, 6vw, 40px);
  font-weight: 250;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink);
  max-width: 22ch;
}

.page-about .about-sec-lede {
  margin: 0 0 26px;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-2);
}

.page-about .about-sec-body p {
  max-width: 66ch;
  margin: 0 0 20px;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--ink-2);
}

.page-about .about-sec-body p:last-child {
  margin-bottom: 0;
}

.page-about .about-sec-body--tail {
  margin-top: 26px;
}

.page-about .about-em {
  color: var(--ink);
}

.page-about .about-quote {
  position: relative;
  margin: 36px 0 0;
  padding: 4px 0 4px 22px;
  max-width: 46ch;
  font-size: 19px;
  font-weight: 200;
  line-height: 1.65;
  color: var(--ink);
}

.page-about .about-quote::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--grad-seasons);
}

/* ---------- 方法四步 ---------- */
.page-about .about-method {
  display: grid;
  gap: 34px;
}

.page-about .about-step {
  border: 2px solid var(--line);
  background: var(--panel);
  box-shadow: var(--hard-sm);
  margin-bottom: 12px;
  transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .about-step:last-child {
  margin-bottom: 0;
}

.page-about .about-step[open] {
  border-color: var(--summer);
  box-shadow: 6px 6px 0 rgba(255, 138, 60, 0.22);
}

.page-about .about-step-sum {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr) 20px;
  align-items: center;
  gap: 12px;
  padding: 15px 16px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-step-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  font-weight: 600;
  color: var(--summer);
}

.page-about .about-step-name {
  font-size: 15px;
  color: var(--ink);
  letter-spacing: 0.01em;
}

.page-about .about-step-mark {
  position: relative;
  width: 14px;
  height: 14px;
}

.page-about .about-step-mark::before,
.page-about .about-step-mark::after {
  content: "";
  position: absolute;
  background: var(--ink-2);
  transition: transform var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-step-mark::before {
  left: 0;
  top: 6px;
  width: 14px;
  height: 2px;
}

.page-about .about-step-mark::after {
  left: 6px;
  top: 0;
  width: 2px;
  height: 14px;
}

.page-about .about-step[open] .about-step-mark::after {
  transform: scaleY(0);
}

.page-about .about-step[open] .about-step-mark::before {
  background: var(--summer);
}

.page-about .about-step-body {
  padding: 0 18px 18px 66px;
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.page-about .about-step-body p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-2);
  max-width: 60ch;
}

.page-about .about-method-media {
  margin: 0;
}

.page-about .about-method-media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
}

/* ---------- 团队 ---------- */
.page-about .about-team-banner {
  position: relative;
  margin: 0 0 34px;
}

.page-about .about-team-banner img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 7;
  object-fit: cover;
  opacity: 0.62;
}

.page-about .about-team-banner::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--grad-glow);
  pointer-events: none;
}

.page-about .about-team-grid {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-team-card {
  background: var(--panel);
  border: 2px solid var(--line);
  border-top-width: 4px;
  box-shadow: var(--hard-sm);
  padding: 22px 20px 24px;
}

.page-about .about-team-card--spring { border-top-color: var(--spring); }
.page-about .about-team-card--summer { border-top-color: var(--summer); }
.page-about .about-team-card--autumn { border-top-color: var(--autumn); }
.page-about .about-team-card--winter { border-top-color: var(--winter); }

.page-about .about-team-count {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(30px, 8vw, 42px);
  font-weight: 600;
  line-height: 1;
  color: var(--ink);
}

.page-about .about-team-card--spring .about-team-count { color: var(--spring); }
.page-about .about-team-card--summer .about-team-count { color: var(--summer); }
.page-about .about-team-card--autumn .about-team-count { color: var(--autumn); }
.page-about .about-team-card--winter .about-team-count { color: var(--winter); }

.page-about .about-team-card h3 {
  margin: 14px 0 10px;
  font-size: 16.5px;
  font-weight: 400;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .about-team-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--ink-2);
}

/* ---------- 时间线 ---------- */
.page-about .about-section--timeline {
  overflow: hidden;
}

.page-about .about-timeline-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

.page-about .about-timeline-bg img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.14;
}

.page-about .about-timeline-inner {
  position: relative;
  z-index: 1;
}

.page-about .about-timeline-scroll {
  margin-top: 8px;
}

.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 26px;
}

.page-about .about-tl-svg {
  display: none;
}

.page-about .about-tl-item {
  position: relative;
  padding-left: 26px;
}

.page-about .about-tl-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 5px;
  width: 12px;
  height: 12px;
  border: 2px solid var(--line);
  background: var(--spring);
}

.page-about .about-tl-item:nth-child(4n+1)::before { background: var(--spring); }
.page-about .about-tl-item:nth-child(4n+2)::before { background: var(--summer); }
.page-about .about-tl-item:nth-child(4n+3)::before { background: var(--autumn); }
.page-about .about-tl-item:nth-child(4n+4)::before { background: var(--winter); }

.page-about .about-tl-phase {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.page-about .about-tl-name {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 400;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .about-tl-text {
  margin: 0 0 10px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--ink-2);
}

.page-about .about-tl-count {
  margin: 0;
  padding-top: 8px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  color: var(--ink-3);
  transition: color var(--dur) var(--ease);
}

.page-about .about-tl-item:hover .about-tl-count {
  color: var(--ink);
}

/* ---------- 合作 ---------- */
.page-about .about-partners {
  margin-top: 28px;
  display: grid;
  gap: 2px;
  padding: 2px;
  background: var(--line);
  border: 2px solid var(--line);
}

.page-about .about-partner-block {
  background: var(--panel);
  padding: 26px 22px 28px;
  border-top: 4px solid var(--line);
}

.page-about .about-partner-block--winter { border-top-color: var(--winter); }
.page-about .about-partner-block--autumn { border-top-color: var(--autumn); }

.page-about .about-partner-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(28px, 7vw, 38px);
  font-weight: 600;
  line-height: 1;
  color: var(--ink);
}

.page-about .about-partner-block--winter .about-partner-num { color: var(--winter); }
.page-about .about-partner-block--autumn .about-partner-num { color: var(--autumn); }

.page-about .about-partner-block h3 {
  margin: 12px 0 10px;
  font-size: 16.5px;
  font-weight: 400;
  color: var(--ink);
}

.page-about .about-partner-block p {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--ink-2);
}

/* ---------- 三点理由 ---------- */
.page-about .about-promise {
  list-style: none;
  margin: 28px 0 0;
  padding: 2px;
  display: grid;
  gap: 2px;
  background: var(--line);
  border: 2px solid var(--line);
}

.page-about .about-promise li {
  background: var(--bg);
  padding: 22px 20px 24px;
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-promise-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  font-weight: 600;
  color: var(--autumn);
  padding-top: 3px;
}

.page-about .about-promise-body h3 {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 400;
  line-height: 1.45;
  color: var(--ink);
}

.page-about .about-promise-body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: var(--ink-2);
  max-width: 62ch;
}

.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 34px;
}

/* ---------- 断点 ---------- */
@media (min-width: 620px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about {
    padding-block: 40px 120px;
  }

  .page-about .about-display {
    font-size: clamp(64px, 9vw, 116px);
  }

  .page-about .about-lede {
    font-size: 17px;
  }

  .page-about .about-head {
    padding-bottom: 60px;
  }

  .page-about .about-body {
    margin-top: 72px;
    grid-template-columns: var(--about-idx-w) minmax(0, 1fr);
    gap: 64px;
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: 96px;
  }

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

  .page-about .about-section {
    padding-block: 84px;
  }

  .page-about .about-quote {
    font-size: 22px;
  }

  .page-about .about-method {
    grid-template-columns: minmax(0, 1fr) minmax(0, 400px);
    gap: 48px;
    align-items: start;
  }

  .page-about .about-timeline-scroll {
    overflow-x: auto;
    padding-bottom: 14px;
  }

  .page-about .about-timeline {
    width: max-content;
    grid-template-columns: repeat(6, 236px);
    gap: 20px;
    padding-top: 38px;
  }

  .page-about .about-tl-svg {
    display: block;
    position: absolute;
    top: 6px;
    left: 0;
    width: 100%;
    height: 4px;
  }

  .page-about .about-tl-item {
    padding-left: 0;
    padding-right: 10px;
  }

  .page-about .about-tl-item::before {
    top: -32px;
    left: 0;
  }
}

@media (min-width: 1100px) {
  .page-about {
    --about-idx-w: 264px;
  }

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

  .page-about .about-promise li {
    grid-template-columns: 46px minmax(0, 1fr);
    padding: 26px 24px 28px;
  }

  .page-about .about-partner-block {
    padding: 30px 28px 32px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-step,
  .page-about .about-index-link,
  .page-about .about-tl-count,
  .page-about .about-step-mark::before,
  .page-about .about-step-mark::after {
    transition: none;
  }
}
<<<END>>>