.page-about {
  --ab-line: 1px solid var(--c-grid);
  --ab-rail: 62px;
  background-color: var(--c-deep);
  color: var(--c-white);
}

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

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(20px, 3.6vw, 40px) clamp(36px, 6vw, 76px);
  border-bottom: var(--ab-line);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(30, 58, 95, 0.55) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(30, 58, 95, 0.55) 1px, transparent 1px);
  background-size: 96px 96px;
  -webkit-mask-image: radial-gradient(130% 90% at 12% 0%, #000 0%, transparent 72%);
  mask-image: radial-gradient(130% 90% at 12% 0%, #000 0%, transparent 72%);
  pointer-events: none;
}

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

.page-about .about-hero .breadcrumbs {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--c-titan);
  margin-bottom: clamp(20px, 3vw, 40px);
}

.page-about .about-hero .breadcrumbs a {
  color: var(--c-ice);
  text-decoration: none;
}

.page-about .about-hero .breadcrumbs a:hover,
.page-about .about-hero .breadcrumbs a:focus-visible {
  color: var(--c-pure);
  border-bottom: 1px solid var(--c-cyan);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(18px, 3vw, 40px);
}

.page-about .about-hero__rail {
  display: none;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-size: clamp(38px, 7.6vw, 76px);
  line-height: 1.06;
  font-weight: 900;
  letter-spacing: -0.02em;
  max-width: 13em;
  color: var(--c-pure);
}

.page-about .about-hero__lead {
  margin-top: clamp(16px, 2.2vw, 26px);
  max-width: 40em;
  font-size: clamp(16px, 1.35vw, 18px);
  line-height: 1.8;
  color: var(--c-ice);
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px clamp(14px, 2vw, 26px);
  margin-top: clamp(20px, 2.8vw, 32px);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 2.8vw, 32px);
}

.page-about .about-hero__figure {
  margin: clamp(30px, 5vw, 60px) 0 0;
}

.page-about .about-hero__figure .media-frame {
  border-top: 2px solid var(--c-cyan);
}

/* ---------- 章节索引条 ---------- */
.page-about .about-toc {
  border-bottom: var(--ab-line);
  background-color: var(--c-deep-2);
}

.page-about .about-toc__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px clamp(16px, 3vw, 40px);
  padding-block: 16px;
}

.page-about .about-toc__label {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--c-cyan);
}

.page-about .about-toc__list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px clamp(14px, 2.4vw, 34px);
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-toc__list .index-list__item {
  margin: 0;
}

.page-about .about-toc__list .index-link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  font-size: 14px;
  color: var(--c-ice);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color 0.22s var(--ease), border-color 0.22s var(--ease);
}

.page-about .about-toc__list .index-link:hover,
.page-about .about-toc__list .index-link:focus-visible {
  color: var(--c-pure);
  border-color: var(--c-cyan);
}

.page-about .about-toc__list .index-link.is-current {
  color: var(--c-pure);
  border-color: var(--c-orange);
}

.page-about .about-toc__list .index-list__num {
  font-size: 12px;
  color: var(--c-cyan);
}

/* ---------- 通用章节 ---------- */
.page-about .about-section {
  padding-block: clamp(44px, 6.5vw, 92px);
  border-bottom: var(--ab-line);
}

.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
}

.page-about .about-split__aside .section-head__index {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--c-cyan);
}

.page-about .about-split__aside .section-head__title {
  margin: 12px 0 0;
  font-size: clamp(26px, 4.2vw, 44px);
  line-height: 1.18;
  font-weight: 800;
  color: var(--c-pure);
  max-width: 11em;
}

.page-about .about-split__aside .section-head__note {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--c-titan);
  padding-left: 12px;
  border-left: 2px solid var(--c-grid);
}

.page-about .about-section__head .section-head__index {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--c-cyan);
}

.page-about .about-section__head .section-head__title {
  margin: 12px 0 0;
  font-size: clamp(26px, 4.2vw, 44px);
  line-height: 1.18;
  font-weight: 800;
  color: var(--c-pure);
  max-width: 16em;
}

.page-about .about-section__head .section-head__note {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--c-titan);
  max-width: 52em;
}

.page-about .about-section .prose p {
  margin: 0;
  font-size: clamp(15.5px, 1.25vw, 17.5px);
  line-height: 1.85;
  color: var(--c-white);
}

.page-about .about-section .prose p + p {
  margin-top: 1em;
}

.page-about .about-lead-small {
  margin: 0;
  font-size: clamp(15.5px, 1.2vw, 17px);
  line-height: 1.8;
  color: var(--c-ice);
}

/* ---------- 仪表板数字 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 1px;
  margin-top: clamp(22px, 3vw, 34px);
  background-color: var(--c-grid);
  border: var(--ab-line);
}

.page-about .about-stats .stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 16px;
  background-color: var(--c-deep);
}

.page-about .about-stats .stat__value {
  font-family: var(--font-mono);
  font-size: clamp(22px, 2.4vw, 30px);
  font-weight: 700;
  color: var(--c-cyan);
  line-height: 1.1;
}

.page-about .about-stats .stat__label {
  font-size: 13px;
  color: var(--c-titan);
}

/* ---------- 图片单元 ---------- */
.page-about .about-figure {
  margin: clamp(24px, 3.4vw, 40px) 0 0;
}

.page-about .about-figure--wide {
  margin-top: clamp(26px, 3.6vw, 44px);
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-titan);
}

/* ---------- 版本时间线 ---------- */
.page-about .version-timeline {
  position: relative;
  margin-top: clamp(30px, 4.4vw, 54px);
  padding-left: 30px;
}

.page-about .version-timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(180deg, var(--c-cyan) 0%, var(--c-grid) 45%, var(--c-orange) 100%);
}

.page-about .version-node {
  position: relative;
  padding-bottom: clamp(26px, 3.6vw, 42px);
}

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

.page-about .version-node::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 7px;
  width: 13px;
  height: 13px;
  background-color: var(--c-deep);
  border: 1px solid var(--c-cyan);
  transform: rotate(45deg);
}

.page-about .version-node--current::before {
  background-color: var(--c-orange);
  border-color: var(--c-orange);
}

.page-about .version-node__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 14px;
}

.page-about .version-node__code {
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--c-cyan);
}

.page-about .version-node__time {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--c-titan);
}

.page-about .version-node__title {
  margin: 12px 0 0;
  font-size: clamp(18px, 2vw, 23px);
  font-weight: 700;
  line-height: 1.4;
  color: var(--c-pure);
}

.page-about .version-node__desc {
  margin: 10px 0 0;
  max-width: 46em;
  font-size: 15px;
  line-height: 1.8;
  color: var(--c-white);
}

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

.page-about .version-node__more summary {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 6px 0;
  list-style: none;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--c-cyan);
}

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

.page-about .version-node__more summary:focus-visible {
  outline: 1px solid var(--c-cyan);
  outline-offset: 3px;
}

.page-about .version-node__mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  border: 1px solid var(--c-cyan);
  font-size: 12px;
  line-height: 1;
  transition: transform 0.25s var(--ease);
}

.page-about .version-node__more[open] .version-node__mark {
  transform: rotate(45deg);
}

.page-about .version-node__list {
  margin: 10px 0 0;
  padding-left: 18px;
  font-size: 14px;
  line-height: 1.85;
  color: var(--c-titan);
}

/* ---------- 咨询卡片 ---------- */
.page-about .cs-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(14px, 2.2vw, 24px);
  margin-top: clamp(22px, 3vw, 34px);
}

.page-about .cs-card {
  padding: 20px 18px;
  border: var(--ab-line);
  border-top: 2px solid var(--c-cyan);
  background: linear-gradient(180deg, rgba(0, 229, 255, 0.07), rgba(10, 22, 51, 0) 62%);
}

.page-about .cs-card__title {
  margin: 0 0 12px;
  font-size: 17px;
  font-weight: 700;
  color: var(--c-pure);
}

.page-about .cs-card__list {
  margin: 0;
  padding-left: 18px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--c-ice);
}

.page-about .about-callout {
  margin-top: clamp(22px, 3vw, 32px);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 20px;
}

.page-about .about-callout p {
  margin: 0;
  flex: 1 1 260px;
  font-size: 15px;
  line-height: 1.75;
}

/* ---------- 团队分工 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(14px, 2.2vw, 24px);
  margin-top: clamp(26px, 3.6vw, 42px);
}

.page-about .team-card {
  padding: 22px 20px;
  border: var(--ab-line);
  border-left: 2px solid var(--c-orange);
  background-color: var(--c-deep-2);
}

.page-about .team-card__role {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--c-orange);
}

.page-about .team-card__title {
  margin: 12px 0 0;
  font-size: 18px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--c-pure);
}

.page-about .team-card__desc {
  margin: 10px 0 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--c-titan);
}

.page-about .about-team-note {
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--c-cyan);
  max-width: 60em;
  font-size: 15px;
  line-height: 1.8;
  color: var(--c-ice);
}

/* ---------- 相关页面 ---------- */
.page-about .about-next {
  padding-block: clamp(40px, 6vw, 80px);
  background-color: var(--c-deep-2);
}

.page-about .about-next__title {
  margin: 0 0 clamp(18px, 2.6vw, 30px);
  font-size: clamp(20px, 2.4vw, 28px);
  font-weight: 800;
  color: var(--c-pure);
}

.page-about .next-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background-color: var(--c-grid);
  border: var(--ab-line);
}

.page-about .next-link {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 20px 18px;
  background-color: var(--c-deep-2);
  text-decoration: none;
  transition: background-color 0.22s var(--ease);
}

.page-about .next-link:hover,
.page-about .next-link:focus-visible {
  background-color: rgba(0, 229, 255, 0.08);
}

.page-about .next-link__label {
  font-size: 16px;
  font-weight: 700;
  color: var(--c-pure);
}

.page-about .next-link__label::after {
  content: " →";
  color: var(--c-orange);
}

.page-about .next-link__desc {
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--c-titan);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .cs-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: clamp(24px, 3.4vw, 48px);
  }

  .page-about .about-hero__rail {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    padding-block: 6px 40px;
    border-right: var(--ab-line);
  }

  .page-about .about-hero__rail-text,
  .page-about .about-hero__rail-code {
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 11.5px;
  }

  .page-about .about-hero__rail-text {
    letter-spacing: 0.34em;
    color: var(--c-titan);
  }

  .page-about .about-hero__rail-code {
    letter-spacing: 0.2em;
    color: var(--c-cyan);
  }
}

@media (min-width: 1000px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 0.82fr) minmax(0, 1.62fr);
    gap: clamp(32px, 4.4vw, 76px);
  }

  .page-about .about-split--flip .about-split__aside {
    order: 2;
  }

  .page-about .about-split--flip .about-split__body {
    order: 1;
  }

  .page-about .about-next__title {
    max-width: 20em;
  }
}

@media (min-width: 1120px) {
  .page-about .next-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-toc__list .index-link,
  .page-about .version-node__mark,
  .page-about .next-link {
    transition: none;
  }
}
<<<END>>>