.page-about {
  --about-line-dark: rgba(244, 240, 232, 0.16);
  --about-line-light: rgba(6, 11, 26, 0.16);
  --about-muted-light: rgba(244, 240, 232, 0.74);
  --about-muted-ink: rgba(6, 11, 26, 0.68);
  background: var(--paper);
  color: var(--ink);
}

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

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  margin-top: calc(var(--bar-h) * -1);
  padding: calc(var(--bar-h) + 48px) 0 56px;
  background:
    radial-gradient(120% 90% at 88% 0%, rgba(47, 240, 214, 0.16), transparent 62%),
    linear-gradient(165deg, var(--deep) 0%, var(--ink) 64%);
  color: var(--paper);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.5;
  background-image:
    repeating-linear-gradient(90deg, rgba(42, 58, 85, 0.55) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(0deg, rgba(42, 58, 85, 0.38) 0 1px, transparent 1px 96px);
}

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

.page-about .about-hero .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 26px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--about-muted-light);
}

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

.page-about .about-hero .breadcrumb a:hover {
  text-decoration: underline;
}

.page-about .about-hero .breadcrumb__sep {
  opacity: 0.5;
}

.page-about .about-hero .breadcrumb__current {
  color: var(--paper);
}

.page-about .about-hero .index-label {
  color: var(--cyan);
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--sans);
  font-weight: 800;
  font-size: clamp(32px, 7.2vw, 74px);
  line-height: 1.08;
  letter-spacing: -0.01em;
}

.page-about .about-hero__lede {
  margin: 22px 0 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--about-muted-light);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 40px 0 0;
  padding: 22px 0 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 16px;
  border-top: 1px solid var(--about-line-dark);
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}

.page-about .about-stat__num {
  font-family: var(--mono);
  font-size: clamp(25px, 5vw, 40px);
  font-weight: 200;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-stat__label {
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.04em;
  color: var(--about-muted-light);
}

@media (min-width: 560px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 主体双栏 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 36px;
  padding-top: 44px;
  padding-bottom: 76px;
}

/* ---------- 左侧章节索引 ---------- */
.page-about .about-rail {
  border: 1px solid var(--line);
  background: var(--deep);
  color: var(--paper);
  padding: 16px 16px 14px;
  min-width: 0;
}

.page-about .about-rail__title {
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--cyan);
}

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

.page-about .about-rail__item {
  flex: 0 0 auto;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 7px 10px;
  border: 1px solid transparent;
  color: var(--about-muted-light);
  text-decoration: none;
  font-size: 13px;
  line-height: 1.4;
  white-space: nowrap;
}

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

.page-about .about-rail__no {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

/* ---------- 右侧内容流 ---------- */
.page-about .about-flow {
  display: grid;
  gap: 52px;
  min-width: 0;
}

.page-about .about-chapter {
  min-width: 0;
  border-top: 1px solid var(--about-line-light);
  padding-top: 24px;
}

.page-about .about-chapter__no {
  margin: 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--orange-deep);
}

.page-about .about-chapter__title {
  margin: 10px 0 0;
  font-size: clamp(23px, 4vw, 33px);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-pull {
  margin: 24px 0 0;
  padding-left: 18px;
  border-left: 2px solid var(--orange);
  max-width: 26ch;
  font-size: clamp(21px, 3.6vw, 34px);
  font-weight: 300;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--night);
}

.page-about .about-chapter .prose {
  margin: 22px 0 0;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .about-chapter .prose p {
  margin: 0 0 14px;
}

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

/* 深色章节 */
.page-about .about-chapter--ink,
.page-about .about-chapter--deep {
  padding: 28px 20px 32px;
  border-top-color: var(--line);
}

.page-about .about-chapter--ink {
  background: var(--ink);
  color: var(--paper);
}

.page-about .about-chapter--deep {
  background: var(--deep);
  color: var(--paper);
}

.page-about .about-chapter--ink .about-chapter__no,
.page-about .about-chapter--deep .about-chapter__no {
  color: var(--orange);
}

.page-about .about-chapter--ink .about-chapter__title,
.page-about .about-chapter--deep .about-chapter__title {
  color: var(--paper);
}

.page-about .about-chapter--ink .about-pull,
.page-about .about-chapter--deep .about-pull {
  color: var(--cyan-mist);
}

.page-about .about-chapter--ink .prose,
.page-about .about-chapter--deep .prose {
  color: var(--about-muted-light);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 30px 0 0;
}

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

.page-about .about-figure--tall {
  max-width: 360px;
}

.page-about .about-figure__cap {
  margin: 10px 0 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  line-height: 1.6;
  color: var(--about-muted-ink);
}

.page-about .about-chapter--ink .about-figure img,
.page-about .about-chapter--deep .about-figure img {
  border-color: var(--about-line-dark);
}

.page-about .about-chapter--ink .about-figure__cap,
.page-about .about-chapter--deep .about-figure__cap {
  color: var(--about-muted-light);
}

.page-about .about-cover {
  margin: 24px 0 26px;
}

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

/* ---------- 三步流程 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .about-step {
  position: relative;
  min-width: 0;
  padding: 0 0 24px 20px;
  border-left: 1px solid var(--about-line-light);
}

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

.page-about .about-step::before {
  content: "";
  position: absolute;
  left: -3px;
  top: 6px;
  width: 5px;
  height: 5px;
  background: var(--ink);
}

.page-about .about-step__no {
  margin: 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--orange-deep);
}

.page-about .about-step__title {
  margin: 6px 0 0;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .about-step__text {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--about-muted-ink);
}

/* ---------- 团队岗位条 ---------- */
.page-about .about-roles {
  margin-top: 30px;
}

.page-about .about-roles__title {
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--cyan);
}

.page-about .about-share {
  display: flex;
  height: 44px;
  border: 1px solid var(--about-line-dark);
}

.page-about .about-share__seg {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 0;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.page-about .about-share__seg--edit {
  flex: 14;
  background: var(--cyan);
}

.page-about .about-share__seg--eng {
  flex: 11;
  background: var(--cyan-mist);
  border-left: 1px solid var(--about-line-dark);
}

.page-about .about-share__seg--ops {
  flex: 21;
  background: var(--night);
  border-left: 1px solid var(--about-line-dark);
  color: var(--paper);
}

.page-about .about-roles__legend {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  font-size: 12px;
  color: var(--about-muted-light);
}

.page-about .about-roles__legend li {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.page-about .about-roles__dot {
  display: inline-block;
  width: 9px;
  height: 9px;
}

.page-about .about-roles__dot--edit { background: var(--cyan); }
.page-about .about-roles__dot--eng { background: var(--cyan-mist); }
.page-about .about-roles__dot--ops { background: var(--night); }

/* ---------- 版本时间线 ---------- */
.page-about .about-versions {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.page-about .about-version {
  position: relative;
  padding: 0 0 26px 22px;
  border-left: 1px solid var(--about-line-light);
}

.page-about .about-version:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .about-version::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 3px;
  width: 7px;
  height: 7px;
  background: var(--paper);
  border: 1px solid var(--orange-deep);
}

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

.page-about .about-version__tag {
  margin: 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--orange-deep);
}

.page-about .about-version__title {
  margin: 6px 0 0;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .about-version__text {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--about-muted-ink);
}

/* ---------- 覆盖范围数据格 ---------- */
.page-about .about-metrics {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--about-line-dark);
  border-left: 1px solid var(--about-line-dark);
}

.page-about .about-metric {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
  padding: 16px 14px;
  border-right: 1px solid var(--about-line-dark);
  border-bottom: 1px solid var(--about-line-dark);
}

.page-about .about-metric__num {
  font-family: var(--mono);
  font-size: clamp(22px, 3.4vw, 30px);
  font-weight: 200;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-metric__label {
  font-size: 12px;
  line-height: 1.5;
  color: var(--about-muted-light);
}

@media (min-width: 640px) {
  .page-about .about-metrics {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 合作生态 ---------- */
.page-about .about-eco {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

.page-about .about-eco li {
  border-left: 2px solid var(--orange);
  padding: 2px 0 2px 14px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--about-muted-ink);
}

.page-about .about-eco__num {
  display: block;
  margin-bottom: 4px;
  font-family: var(--mono);
  font-size: 24px;
  font-weight: 200;
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--ink);
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-chapter--ink .btn--line {
  color: var(--paper);
  border-color: rgba(244, 240, 232, 0.42);
}

.page-about .about-chapter--ink .btn--line:hover,
.page-about .about-chapter--ink .btn--line:focus-visible {
  color: var(--cyan);
  border-color: var(--cyan);
}

.page-about .about-cta__note {
  margin: 20px 0 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--about-muted-light);
}

.page-about .about-cta__note a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(47, 240, 214, 0.4);
}

.page-about .about-cta__note a:hover {
  border-bottom-color: var(--cyan);
}

/* ---------- 桌面：左侧刻度常驻 ---------- */
@media (min-width: 900px) {
  .page-about .about-body {
    grid-template-columns: 186px minmax(0, 1fr);
    gap: 64px;
    padding-top: 72px;
    padding-bottom: 120px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--bar-h) + 28px);
    align-self: start;
    padding: 22px 18px;
  }

  .page-about .about-rail__list {
    display: block;
    overflow: visible;
  }

  .page-about .about-rail__item {
    flex: none;
    border-top: 1px solid var(--about-line-dark);
  }

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

  .page-about .about-rail__link {
    display: flex;
    width: 100%;
    padding: 12px 0 12px 16px;
    border: 0;
    position: relative;
  }

  .page-about .about-rail__link::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    width: 8px;
    height: 1px;
    background: var(--cyan);
    opacity: 0.6;
    transform: translateY(-50%);
    transition: width 240ms ease, opacity 240ms ease;
  }

  .page-about .about-rail__link:hover::before,
  .page-about .about-rail__link:focus-visible::before {
    width: 16px;
    opacity: 1;
  }

  .page-about .about-flow {
    gap: 88px;
  }

  .page-about .about-chapter--ink,
  .page-about .about-chapter--deep {
    padding: 40px 36px 44px;
  }
}

@media (min-width: 1180px) {
  .page-about .about-figure--tall {
    max-width: 420px;
  }

  .page-about .about-eco {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link::before {
    transition: none;
  }
}
<<<END>>>