.page-about {
  --about-hair: rgba(43, 59, 82, 0.85);
  --about-cyan-soft: rgba(34, 230, 211, 0.3);
  --about-index-w: 196px;
  color: rgba(244, 241, 234, 0.86);
  padding-bottom: clamp(40px, 7vw, 96px);
}

.page-about img {
  display: block;
  max-width: 100%;
  height: auto;
}

/* 面包屑 */
.page-about .breadcrumb {
  padding-top: clamp(16px, 3vw, 30px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .breadcrumb a {
  color: var(--mist);
  text-decoration: none;
}

.page-about .breadcrumb a:hover {
  color: var(--cyan);
}

.page-about .breadcrumb__sep {
  padding: 0 8px;
  color: rgba(169, 184, 200, 0.45);
}

/* 首屏 */
.page-about .about-hero {
  position: relative;
  padding: clamp(24px, 4.6vw, 58px) 0 clamp(26px, 4vw, 46px);
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: clamp(64px, 14vw, 156px);
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), rgba(34, 230, 211, 0));
}

.page-about .about-hero__kicker {
  margin: 0 0 clamp(14px, 2.4vw, 22px);
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .about-hero h1 {
  margin: 0;
  max-width: 22ch;
  font-size: clamp(27px, 5.2vw, 56px);
  line-height: 1.16;
  letter-spacing: -0.02em;
  font-weight: 800;
  color: var(--paper);
}

.page-about .about-hero__lede {
  margin: clamp(18px, 3vw, 30px) 0 0;
  max-width: 64ch;
  font-size: clamp(15px, 1.4vw, 17px);
  line-height: 1.85;
  color: rgba(169, 184, 200, 0.96);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 14px;
  margin: clamp(26px, 4vw, 44px) 0 0;
}

.page-about .about-facts__item {
  border-top: 1px solid var(--about-cyan-soft);
  padding-top: 10px;
}

.page-about .about-facts__label {
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

.page-about .about-facts__num {
  margin: 6px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(19px, 2.4vw, 28px);
  line-height: 1.2;
  color: var(--cyan);
  letter-spacing: -0.01em;
}

/* 布局 */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 56px);
  padding-top: clamp(28px, 5vw, 60px);
}

/* 章节索引 */
.page-about .about-index__label {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: rgba(169, 184, 200, 0.6);
}

.page-about .about-index__list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-index__list > li {
  flex: 0 0 auto;
}

.page-about .about-index__link {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 7px 11px;
  border: 1px solid var(--about-hair);
  border-radius: var(--radius);
  font-size: 12.5px;
  color: var(--mist);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.18s ease, border-color 0.18s ease, background-color 0.18s ease;
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--cyan);
  border-color: var(--about-cyan-soft);
  background: rgba(34, 230, 211, 0.06);
}

.page-about .about-index__no {
  font-size: 10.5px;
  color: rgba(124, 108, 255, 0.9);
}

/* 章节通用 */
.page-about .about-section {
  padding-block: clamp(28px, 4.4vw, 52px);
  border-top: 1px solid var(--about-hair);
}

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

.page-about .about-section .section-head__kicker {
  color: var(--violet);
  letter-spacing: 0.16em;
  font-size: 11.5px;
  margin-bottom: 10px;
}

.page-about .about-section .section-head__title {
  color: var(--paper);
  font-size: clamp(21px, 2.8vw, 30px);
  line-height: 1.34;
  letter-spacing: -0.01em;
}

.page-about .about-prose {
  margin-top: clamp(16px, 2.6vw, 26px);
}

.page-about .about-prose p,
.page-about .about-prose__single {
  max-width: 66ch;
  margin: 0 0 1.1em;
  font-size: 15px;
  line-height: 1.9;
  color: rgba(169, 184, 200, 0.96);
}

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

.page-about .about-prose__single {
  margin-top: clamp(14px, 2.4vw, 22px);
}

.page-about .about-lead {
  max-width: 62ch;
  margin: clamp(14px, 2.4vw, 22px) 0 0;
  font-size: 15px;
  line-height: 1.9;
  color: rgba(244, 241, 234, 0.78);
}

/* 图片 */
.page-about .about-figure {
  margin: clamp(22px, 3.4vw, 34px) 0 0;
}

.page-about .media-frame {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--about-hair);
}

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

.page-about .about-figure__cap {
  margin: 10px 0 0;
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: rgba(169, 184, 200, 0.66);
}

/* 团队角色 */
.page-about .about-roles {
  margin: clamp(16px, 2.6vw, 24px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-roles__item {
  display: grid;
  gap: 6px;
  padding: clamp(15px, 2.2vw, 21px) 0;
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-roles__item:first-child {
  border-top: 1px solid var(--about-hair);
}

.page-about .about-roles__name {
  margin: 0;
  font-size: 16px;
  font-weight: 600;
  color: var(--cyan);
  letter-spacing: 0.01em;
}

.page-about .about-roles__desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(169, 184, 200, 0.94);
}

/* 五步流程 */
.page-about .about-steps {
  counter-reset: about-step;
  margin: clamp(18px, 2.8vw, 28px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-steps__item {
  position: relative;
  padding: 0 0 clamp(20px, 3vw, 32px) clamp(48px, 8vw, 72px);
}

.page-about .about-steps__item::before {
  counter-increment: about-step;
  content: counter(about-step, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: -3px;
  padding: 4px 7px;
  border: 1px solid var(--about-cyan-soft);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1;
  color: var(--cyan);
  background: rgba(34, 230, 211, 0.05);
}

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

.page-about .about-steps__name {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-steps__desc {
  margin: 0;
  max-width: 62ch;
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(169, 184, 200, 0.94);
}

/* 版本时间轴 */
.page-about .about-timeline {
  position: relative;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0 0 0 28px;
  list-style: none;
  border-left: 1px solid var(--about-hair);
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: clamp(24px, 3.4vw, 40px);
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -34px;
  top: 6px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 1px solid var(--cyan);
  box-shadow: 0 0 0 4px rgba(34, 230, 211, 0.08);
}

.page-about .about-timeline__item--current::before {
  background: var(--orange);
  border-color: var(--orange);
  box-shadow: 0 0 0 4px rgba(255, 122, 47, 0.14);
}

.page-about .about-timeline__version {
  margin: 0 0 6px;
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-timeline__item--current .about-timeline__version {
  color: var(--orange);
}

.page-about .about-timeline__name {
  margin: 0 0 6px;
  font-size: clamp(16px, 2vw, 18px);
  font-weight: 600;
  color: var(--paper);
  line-height: 1.5;
}

.page-about .about-timeline__desc {
  margin: 0;
  max-width: 62ch;
  font-size: 14.5px;
  line-height: 1.88;
  color: rgba(169, 184, 200, 0.94);
}

/* 合作数据条 */
.page-about .about-partner-figures {
  display: grid;
  gap: 0;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--about-hair);
}

.page-about .about-partner-figures__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: 14px;
  padding: 14px 0;
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-partner-figures__num {
  font-size: clamp(17px, 2vw, 21px);
  color: var(--orange);
  letter-spacing: -0.01em;
}

.page-about .about-partner-figures__text {
  font-size: 14px;
  line-height: 1.75;
  color: rgba(169, 184, 200, 0.94);
}

/* 服务原则 */
.page-about .about-principles {
  display: grid;
  gap: 16px;
  margin: clamp(18px, 2.8vw, 28px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-principles__item {
  padding: 18px 18px 20px;
  background: var(--ink-800);
  border: 1px solid var(--about-hair);
  border-left: 2px solid var(--about-cyan-soft);
  border-radius: var(--radius);
}

.page-about .about-principles__name {
  margin: 0 0 8px;
  font-size: 15.5px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-principles__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: rgba(169, 184, 200, 0.94);
}

/* 行动区 */
.page-about .about-cta {
  display: grid;
  gap: 18px;
  margin-top: clamp(24px, 3.6vw, 38px);
  padding: clamp(20px, 3vw, 30px);
  background: var(--ink-800);
  border: 1px solid var(--about-hair);
  border-left: 2px solid var(--orange);
  border-radius: var(--radius);
}

.page-about .about-cta__text {
  margin: 0;
  max-width: 58ch;
  font-size: 14.5px;
  line-height: 1.88;
  color: rgba(244, 241, 234, 0.86);
}

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

.page-about .about-cta__actions .btn {
  text-decoration: none;
}

/* 中等屏幕 */
@media (min-width: 720px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-roles__item {
    grid-template-columns: 168px minmax(0, 1fr);
    align-items: start;
    gap: clamp(16px, 3vw, 34px);
  }

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

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }
}

/* 桌面：左侧固定索引 + 右侧研究板叙事 */
@media (min-width: 980px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-index-w) minmax(0, 1fr);
    gap: clamp(40px, 5vw, 80px);
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
  }

  .page-about .about-index__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
    border-left: 1px solid var(--about-hair);
  }

  .page-about .about-index__link {
    display: flex;
    width: 100%;
    padding: 8px 0 8px 14px;
    border: 0;
    border-radius: 0;
    background: none;
    position: relative;
    white-space: normal;
  }

  .page-about .about-index__link::before {
    content: "";
    position: absolute;
    left: -1px;
    top: 50%;
    width: 2px;
    height: 0;
    background: var(--cyan);
    transform: translateY(-50%);
    transition: height 0.2s ease;
  }

  .page-about .about-index__link:hover::before,
  .page-about .about-index__link:focus-visible::before {
    height: 18px;
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    background: none;
    border-color: transparent;
  }

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

/* 大屏 */
@media (min-width: 1280px) {
  .page-about {
    --about-index-w: 224px;
  }

  .page-about .about-prose p,
  .page-about .about-prose__single {
    font-size: 15.5px;
  }
}

/* 降低动效偏好 */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__link,
  .page-about .about-index__link::before {
    transition: none;
  }
}
<<<END>>>