.page-about {
  --about-rule: rgba(233, 161, 59, .38);
  --about-num-size: clamp(38px, 9vw, 68px);
  display: block;
  color: var(--mist);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(120% 90% at 12% 0%, rgba(63, 224, 206, .06), transparent 58%),
    linear-gradient(180deg, var(--ink-deep) 0%, var(--ink) 100%);
}

.page-about .about-hero .wrap {
  padding-top: clamp(48px, 9vw, 104px);
  padding-bottom: clamp(34px, 6vw, 72px);
}

.page-about .crumb {
  font-size: 13px;
  color: var(--steel);
  letter-spacing: .02em;
  margin: 0 0 clamp(24px, 5vw, 48px);
}

.page-about .crumb a {
  color: var(--steel);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .crumb a:hover,
.page-about .crumb a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .crumb span {
  margin: 0 8px;
  color: var(--line-strong);
}

.page-about .about-h1 {
  max-width: 18ch;
  margin: 0;
  font-family: var(--sans);
  font-size: clamp(30px, 6.4vw, 60px);
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: -.02em;
  color: var(--mist);
}

.page-about .about-h1::after {
  content: "";
  display: block;
  width: 84px;
  height: 3px;
  margin-top: clamp(20px, 3.5vw, 34px);
  background: var(--amber);
}

.page-about .about-lead {
  max-width: 62ch;
  margin: clamp(20px, 3.5vw, 32px) 0 0;
  font-size: 16px;
  line-height: 1.62;
  color: var(--steel);
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 28px;
  margin: clamp(28px, 5vw, 44px) 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--line);
  list-style: none;
  font-size: 13px;
  color: var(--steel);
}

.page-about .about-hero__meta li {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
}

.page-about .about-hero__meta .mono {
  color: var(--amber);
  font-size: 13px;
}

/* ---------- 章节索引（宽屏固定） ---------- */
.page-about .about-index {
  display: none;
}

/* ---------- 主体与章节 ---------- */
.page-about .about-body {
  position: relative;
}

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

.page-about .about-sec {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  row-gap: 22px;
  padding: clamp(44px, 8vw, 96px) 0;
  border-top: 1px solid var(--line);
  position: relative;
}

.page-about .about-sec:first-child {
  border-top: 0;
}

.page-about .about-sec__no {
  font-family: var(--mono);
  font-size: var(--about-num-size);
  font-weight: 500;
  line-height: .9;
  letter-spacing: -.04em;
  color: var(--amber);
  opacity: .92;
}

.page-about .about-sec__body {
  min-width: 0;
}

.page-about .about-sec__body > p {
  max-width: 62ch;
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.62;
  color: var(--steel);
}

.page-about .about-sec__body > p:last-child {
  margin-bottom: 0;
}

.page-about .about-sec__body .h-sec {
  margin: 0 0 clamp(16px, 3vw, 26px);
  color: var(--mist);
}

.page-about .about-sec__aside {
  min-width: 0;
}

/* ---------- 岗位手风琴 ---------- */
.page-about .about-roles {
  margin-top: clamp(24px, 4vw, 38px);
  border-top: 1px solid var(--line);
}

.page-about .about-roles .acc-item {
  border-bottom: 1px solid var(--line);
}

.page-about .about-roles .acc-btn {
  display: flex;
  align-items: baseline;
  gap: 14px;
  width: 100%;
  padding: 16px 4px;
  background: transparent;
  border: 0;
  color: var(--mist);
  text-align: left;
  cursor: pointer;
  transition: background var(--dur) var(--ease), padding-left var(--dur) var(--ease);
}

.page-about .about-roles .acc-btn:hover {
  background: var(--wash-amber);
  padding-left: 10px;
}

.page-about .about-roles .acc-btn:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .about-role__n {
  flex: 0 0 auto;
  min-width: 2ch;
  font-size: 22px;
  color: var(--amber);
  letter-spacing: -.03em;
}

.page-about .about-role__t {
  flex: 1 1 auto;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -.01em;
}

.page-about .about-roles .acc-sign {
  flex: 0 0 auto;
  align-self: center;
  width: 10px;
  height: 10px;
  border-right: 1px solid var(--steel);
  border-bottom: 1px solid var(--steel);
  transform: rotate(45deg);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-roles .acc-item[data-open] .acc-sign {
  transform: rotate(-135deg);
  border-color: var(--cyan);
}

.page-about .about-roles .acc-panel {
  padding: 0 4px 18px 40px;
}

.page-about .about-roles .acc-panel p {
  max-width: 58ch;
  margin: 0;
  font-size: 14px;
  line-height: 1.66;
  color: var(--steel);
}

/* ---------- 环形分工 ---------- */
.page-about .about-ring {
  margin: 0 0 22px;
  padding: clamp(18px, 3vw, 26px);
  background: var(--panel);
  clip-path: var(--clip-cut);
}

.page-about .about-ring svg {
  display: block;
  width: min(100%, 240px);
  height: auto;
  margin: 0 auto;
}

.page-about .about-ring figcaption {
  margin-top: 14px;
  font-family: var(--mono);
  font-size: 12px;
  line-height: 1.6;
  color: var(--steel);
  text-align: center;
}

/* ---------- 图片容器 ---------- */
.page-about .about-fig {
  margin: 0;
}

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

.page-about .about-fig--tall img {
  aspect-ratio: 3 / 2;
}

.page-about .about-fig figcaption {
  margin-top: 12px;
  padding-left: 12px;
  border-left: 2px solid var(--amber);
  font-size: 13px;
  line-height: 1.6;
  color: var(--steel);
}

/* ---------- 时间线 ---------- */
.page-about .about-tl {
  list-style: none;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 0 0 0 26px;
  border-left: 1px solid var(--about-rule);
}

.page-about .about-tl__item {
  position: relative;
  padding-bottom: clamp(26px, 4vw, 42px);
}

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

.page-about .about-tl__dot {
  position: absolute;
  left: -32px;
  top: 6px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--amber);
  transition: transform var(--dur) var(--ease), background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-tl__item:hover .about-tl__dot,
.page-about .about-tl__item:focus-within .about-tl__dot {
  background: var(--amber);
  border-color: var(--amber-soft);
  transform: scale(1.3);
}

.page-about .about-tl__year {
  margin: 0 0 6px;
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--cyan);
}

.page-about .about-tl__title {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -.01em;
  color: var(--mist);
}

.page-about .about-tl__text {
  max-width: 58ch;
  margin: 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--steel);
}

.page-about .about-tl__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
  opacity: .62;
  transition: opacity var(--dur) var(--ease);
}

.page-about .about-tl__item:hover .about-tl__tags,
.page-about .about-tl__item:focus-within .about-tl__tags {
  opacity: 1;
}

.page-about .about-tl__tags li {
  padding: 3px 9px;
  font-size: 12px;
  color: var(--amber-soft);
  border: 1px solid rgba(233, 161, 59, .34);
  clip-path: var(--clip-sm);
}

.page-about .about-tl__fig {
  margin: 18px 0 0;
  max-width: 360px;
}

.page-about .about-tl__fig img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
  background: var(--panel);
}

.page-about .about-tl__fig figcaption {
  margin-top: 10px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--steel);
}

.page-about .about-tl__item--fig .about-tl__dot {
  border-color: var(--cyan);
}

/* ---------- 三道流程 ---------- */
.page-about .about-steps {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: clamp(24px, 4vw, 38px);
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-step {
  padding: clamp(18px, 3vw, 26px) 4px;
  background: var(--ink);
}

.page-about .about-step__n {
  display: block;
  margin-bottom: 10px;
  font-size: 13px;
  color: var(--amber);
  letter-spacing: .12em;
}

.page-about .about-step .h-sub {
  margin: 0 0 10px;
  color: var(--mist);
}

.page-about .about-step p {
  margin: 0;
  max-width: 46ch;
  font-size: 14px;
  line-height: 1.62;
  color: var(--steel);
}

/* ---------- 用户构成数字 ---------- */
.page-about .about-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(26px, 4vw, 40px);
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-metric {
  padding: clamp(18px, 3vw, 26px) 4px;
  background: var(--ink);
}

.page-about .about-metric__v {
  display: block;
  font-size: clamp(26px, 6vw, 40px);
  color: var(--mist);
  letter-spacing: -.03em;
  line-height: 1.05;
}

.page-about .about-metric:nth-child(1) .about-metric__v,
.page-about .about-metric:nth-child(3) .about-metric__v {
  color: var(--cyan);
}

.page-about .about-metric__k {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  color: var(--steel);
}

/* ---------- 生态面板 ---------- */
.page-about .about-plate {
  padding: clamp(20px, 3vw, 28px);
  background: var(--panel);
  border-left: 3px solid var(--amber);
  clip-path: var(--clip-cut);
}

.page-about .about-plate__k {
  margin: 0;
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--steel);
}

.page-about .about-plate__v {
  margin: 10px 0 2px;
  font-size: clamp(44px, 10vw, 68px);
  line-height: 1;
  color: var(--amber);
  letter-spacing: -.04em;
}

.page-about .about-plate__d {
  margin: 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--steel);
}

.page-about .about-plate .track {
  margin: 18px 0;
}

/* ---------- 下一站 ---------- */
.page-about .about-next {
  border-top: 1px solid var(--line);
  background: var(--ink-deep);
}

.page-about .about-next .wrap {
  padding-top: clamp(40px, 7vw, 76px);
  padding-bottom: clamp(44px, 8vw, 88px);
}

.page-about .about-next .h-sec {
  margin: 0 0 clamp(22px, 4vw, 34px);
  color: var(--mist);
}

.page-about .about-next__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-next__cell {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: clamp(20px, 3vw, 28px) 6px;
  background: var(--ink-deep);
  text-decoration: none;
  transition: background var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .about-next__cell:hover,
.page-about .about-next__cell:focus-visible {
  background: var(--wash-cyan);
  transform: translateY(-2px);
}

.page-about .about-next__cell:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -2px;
}

.page-about .about-next__k {
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--cyan);
}

.page-about .about-next__t {
  font-size: 14px;
  line-height: 1.62;
  color: var(--mist);
}

/* ---------- 窄屏适配 ---------- */
@media (max-width: 479px) {
  .page-about .about-hero__meta {
    gap: 8px 18px;
    font-size: 12px;
  }

  .page-about .about-tl {
    padding-left: 20px;
  }

  .page-about .about-tl__dot {
    left: -26px;
  }

  .page-about .about-roles .acc-panel {
    padding-left: 4px;
  }
}

/* ---------- 桌面栅格 ---------- */
@media (min-width: 768px) {
  .page-about .about-lead {
    font-size: 17px;
  }

  .page-about .about-roles .acc-btn {
    gap: 20px;
  }

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

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

@media (min-width: 1024px) {
  .page-about .about-sec {
    grid-template-columns: 92px minmax(0, 58ch) minmax(0, 1fr);
    column-gap: clamp(24px, 3vw, 44px);
    row-gap: 0;
    align-items: start;
  }

  .page-about .about-sec__no {
    grid-column: 1;
    padding-top: 4px;
  }

  .page-about .about-sec__body {
    grid-column: 2;
  }

  .page-about .about-sec__aside {
    grid-column: 3;
  }

  .page-about .about-sec--wide .about-sec__body {
    grid-column: 2 / 4;
  }

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

  .page-about .about-body::before {
    content: "";
    position: absolute;
    left: calc(var(--wrap) * 0 + 91px);
    top: clamp(44px, 8vw, 96px);
    bottom: clamp(44px, 8vw, 96px);
    width: 1px;
    background: linear-gradient(180deg, transparent, rgba(233, 161, 59, .34) 12%, rgba(233, 161, 59, .34) 88%, transparent);
    pointer-events: none;
  }
}

@media (min-width: 1360px) {
  .page-about .about-index {
    display: flex;
    position: fixed;
    right: 28px;
    top: 50%;
    transform: translateY(-50%);
    flex-direction: column;
    gap: 9px;
    padding-left: 12px;
    border-left: 1px solid var(--line);
    z-index: 6;
  }

  .page-about .about-index__link {
    font-family: var(--mono);
    font-size: 12px;
    line-height: 1;
    letter-spacing: .04em;
    color: var(--steel);
    text-decoration: none;
    padding: 3px 0;
    transition: color var(--dur) var(--ease), transform var(--dur) var(--ease);
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    color: var(--cyan);
    transform: translateX(-2px);
  }

  .page-about .about-index__link[aria-current],
  .page-about .about-index__link[data-active] {
    color: var(--amber);
  }
}
<<<END>>>