.page-about {
  --about-rail-w: 236px;
  --about-radius: 10px;
  display: block;
  background: var(--deep);
  color: var(--mist);
  padding-bottom: clamp(56px, 9vw, 110px);
}

/* ── 面包屑 ───────────────────────────── */
.page-about .about-crumbs {
  padding: clamp(18px, 3vw, 28px) 0 0;
}

/* ── 首屏 ─────────────────────────────── */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(22px, 4vw, 46px) 0 clamp(40px, 6vw, 76px);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -28%;
  right: -14%;
  width: min(760px, 80%);
  height: 150%;
  background: linear-gradient(152deg, rgba(255, 106, 31, 0.22), rgba(255, 106, 31, 0) 62%);
  clip-path: polygon(30% 0, 100% 0, 72% 100%, 0 100%);
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(147, 163, 184, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(147, 163, 184, 0.07) 1px, transparent 1px);
  background-size: 48px 48px;
  -webkit-mask-image: linear-gradient(180deg, #000, transparent 76%);
  mask-image: linear-gradient(180deg, #000, transparent 76%);
  pointer-events: none;
}

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

.page-about .about-hero__kicker {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

.page-about .about-hero__since {
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--cool);
}

.page-about .about-hero__title {
  margin: clamp(16px, 3vw, 28px) 0 0;
  max-width: 18ch;
  font-size: clamp(32px, 6.4vw, 74px);
  line-height: 1.05;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--mist);
}

.page-about .about-hero__title .num {
  color: var(--orange);
  font-weight: 600;
}

.page-about .about-hero__split {
  display: grid;
  gap: clamp(24px, 4vw, 48px);
  margin-top: clamp(24px, 4vw, 44px);
}

.page-about .about-hero__lead {
  margin: 0;
  max-width: 58ch;
  font-size: clamp(16px, 1.5vw, 18px);
  line-height: 1.85;
  color: var(--cool);
}

.page-about .about-figures {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: var(--about-radius);
  overflow: hidden;
}

.page-about .about-figure {
  margin: 0;
  padding: 16px 18px;
  background: var(--navy);
  transition: background 0.25s var(--ease);
}

.page-about .about-figure:hover {
  background: var(--navy-2);
}

.page-about .about-figure .data-figure__value {
  margin: 6px 0 0;
  font-size: clamp(24px, 3.2vw, 38px);
  line-height: 1;
  color: var(--mist);
}

.page-about .about-figure:hover .data-figure__value {
  color: var(--orange);
}

.page-about .about-figure .data-figure__label {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--cool);
}

/* ── 主体两栏 ────────────────────────── */
.page-about .about-body {
  display: grid;
  gap: clamp(28px, 4vw, 56px);
  padding-top: clamp(34px, 5vw, 68px);
}

/* ── 左侧编年索引 ────────────────────── */
.page-about .about-rail {
  position: relative;
  min-width: 0;
}

.page-about .about-rail .rail-index__title {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--cool);
  font-family: var(--font-mono);
}

.page-about .about-rail .rail-index__list {
  display: flex;
  gap: 8px;
  margin: 12px 0 0;
  padding: 0 0 8px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail .rail-index__link {
  position: relative;
  display: block;
  padding: 8px 12px;
  font-size: 14px;
  line-height: 1.4;
  white-space: nowrap;
  color: var(--cool);
  text-decoration: none;
  border: 1px solid var(--line);
  border-radius: 999px;
  transition: color 0.25s var(--ease), background 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .about-rail .rail-index__link:hover,
.page-about .about-rail .rail-index__link:focus-visible {
  color: var(--mist);
  border-color: var(--orange);
}

.page-about .about-rail .rail-index__link[aria-current="true"] {
  color: #0A1930;
  background: var(--orange);
  border-color: var(--orange);
}

/* ── 主区与章节 ─────────────────────── */
.page-about .about-main {
  display: grid;
  gap: clamp(44px, 6vw, 80px);
  min-width: 0;
}

.page-about .about-sec {
  scroll-margin-top: calc(var(--header-h) + 24px);
  position: relative;
  min-width: 0;
}

.page-about .about-sec::before {
  content: "";
  position: absolute;
  top: -18px;
  left: 0;
  width: 56px;
  height: 2px;
  background: linear-gradient(90deg, var(--orange), rgba(255, 106, 31, 0));
}

.page-about .about-sec__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--orange);
}

.page-about .about-sec__title {
  margin: 12px 0 0;
  font-size: clamp(24px, 3.1vw, 38px);
  line-height: 1.22;
  font-weight: 900;
  letter-spacing: -0.01em;
  color: var(--mist);
}

.page-about .about-lede {
  margin: 16px 0 0;
  max-width: 62ch;
  font-size: 17px;
  line-height: 1.8;
  color: var(--cool);
}

.page-about .about-text {
  margin-top: 24px;
  max-width: 66ch;
}

.page-about .about-text p {
  margin: 0 0 18px;
  font-size: 17px;
  line-height: 1.85;
  color: var(--mist);
}

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

.page-about .about-text__close {
  padding-left: 16px;
  border-left: 3px solid var(--live);
  color: var(--cool) !important;
}

.page-about .about-text--after {
  margin-top: 22px;
}

/* ── 图文组合 ───────────────────────── */
.page-about .about-origin {
  display: grid;
  gap: clamp(24px, 3vw, 36px);
  margin-top: 4px;
}

.page-about .about-origin .about-text {
  margin-top: 24px;
}

.page-about .media-frame {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  background: var(--navy);
  overflow: hidden;
}

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

.page-about .media-frame__caption {
  padding: 12px 16px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--cool);
  border-top: 1px solid var(--line-soft);
}

.page-about .about-shot {
  margin-top: 28px;
}

.page-about .about-flowmap {
  margin-top: 32px;
}

.page-about .about-stands {
  margin-top: 26px;
  margin-bottom: 30px;
}

/* ── 团队卡片 ───────────────────────── */
.page-about .team-grid {
  display: grid;
  gap: 14px;
  margin-top: 26px;
}

.page-about .team-card {
  position: relative;
  padding: 22px 20px 24px;
  background: var(--navy);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  transition: border-color 0.25s var(--ease), transform 0.25s var(--ease), background 0.25s var(--ease);
}

.page-about .team-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  border-radius: var(--about-radius) var(--about-radius) 0 0;
}

.page-about .team-card--check::before {
  background: var(--orange);
}

.page-about .team-card--write::before {
  background: var(--warm);
}

.page-about .team-card--build::before {
  background: var(--live);
}

.page-about .team-card:hover,
.page-about .team-card:focus-within {
  border-color: var(--orange);
  background: var(--navy-2);
  transform: translateY(-2px);
}

.page-about .team-card__head {
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex-wrap: wrap;
}

.page-about .team-card__count {
  font-size: clamp(32px, 4vw, 44px);
  line-height: 1;
  font-weight: 600;
  color: var(--orange);
}

.page-about .team-card__name {
  font-size: 19px;
  font-weight: 800;
  color: var(--mist);
}

.page-about .team-card__desc {
  margin: 14px 0 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--cool);
}

/* ── 四步流程 ───────────────────────── */
.page-about .flow {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.page-about .flow__step {
  position: relative;
  margin-left: 14px;
  padding: 0 0 26px 30px;
  border-left: 1px solid var(--line);
}

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

.page-about .flow__no {
  position: absolute;
  left: -15px;
  top: 0;
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--navy-2);
  border: 1px solid var(--steel);
  color: var(--orange);
  font-size: 12px;
  transition: border-color 0.25s var(--ease), color 0.25s var(--ease);
}

.page-about .flow__step:hover .flow__no {
  border-color: var(--orange);
  color: var(--warm);
}

.page-about .flow__title {
  margin: 3px 0 0;
  font-size: 18px;
  font-weight: 800;
  color: var(--mist);
}

.page-about .flow__body {
  margin: 8px 0 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--cool);
}

/* ── 编年时间轴 ─────────────────────── */
.page-about .about-timeline {
  list-style: none;
  margin: 28px 0 0;
  padding: 0 0 0 26px;
  border-left: 2px solid var(--line);
  display: grid;
  gap: 30px;
}

.page-about .about-timeline .timeline__item {
  position: relative;
  min-width: 0;
}

.page-about .about-timeline .timeline__dot {
  position: absolute;
  left: -35px;
  top: 4px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--navy);
  border: 2px solid var(--steel);
  transition: background 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .about-timeline .timeline__item:hover .timeline__dot {
  border-color: var(--orange);
  background: var(--orange);
}

.page-about .about-timeline .timeline__item[data-state="now"] .timeline__dot {
  background: var(--live);
  border-color: var(--live);
  box-shadow: 0 0 0 5px rgba(61, 224, 164, 0.16);
}

.page-about .about-timeline .timeline__time {
  display: block;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--orange);
}

.page-about .about-timeline .timeline__title {
  margin: 6px 0 0;
  font-size: 20px;
  font-weight: 800;
  line-height: 1.35;
  color: var(--mist);
}

.page-about .about-timeline .timeline__body {
  margin: 10px 0 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--cool);
}

/* ── 合作生态 ───────────────────────── */
.page-about .partner-strip {
  display: grid;
  gap: 1px;
  margin-top: 26px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: var(--about-radius);
  overflow: hidden;
}

.page-about .partner-item {
  padding: 20px 18px;
  background: var(--navy);
  transition: background 0.25s var(--ease);
}

.page-about .partner-item:hover,
.page-about .partner-item:focus-within {
  background: var(--navy-2);
}

.page-about .partner-item__num {
  display: block;
  font-size: clamp(26px, 3.2vw, 34px);
  line-height: 1;
  font-weight: 600;
  color: var(--live);
}

.page-about .partner-item__text {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--cool);
}

/* ── 收束区 ─────────────────────────── */
.page-about .about-sec--join {
  padding: clamp(26px, 4vw, 40px) clamp(20px, 3vw, 36px);
  background: linear-gradient(140deg, rgba(255, 106, 31, 0.14), rgba(18, 37, 61, 0.9) 58%);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
}

.page-about .about-sec--join::before {
  display: none;
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

/* ── 断点：窄屏基线已就绪，逐级增强 ── */
@media (min-width: 720px) {
  .page-about .partner-strip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (min-width: 860px) {
  .page-about .about-origin {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.82fr);
    align-items: start;
  }

  .page-about .about-origin .about-text {
    margin-top: 30px;
  }

  .page-about .about-shot {
    margin-top: 56px;
  }

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

  .page-about .flow {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 26px 32px;
  }

  .page-about .flow__step {
    padding-bottom: 0;
    border-left-color: transparent;
    margin-left: 16px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__split {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    align-items: end;
  }
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    align-items: start;
    gap: clamp(40px, 5vw, 72px);
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
  }

  .page-about .about-rail .rail-index__list {
    display: block;
    overflow: visible;
    padding: 0 0 0 20px;
  }

  .page-about .about-rail .rail-index__list::before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: 5px;
    width: 1px;
    background: linear-gradient(180deg, var(--line), rgba(36, 64, 95, 0.1));
  }

  .page-about .about-rail .rail-index__list {
    position: relative;
  }

  .page-about .about-rail .rail-index__link {
    border-color: transparent;
    border-radius: var(--r-s);
    padding: 9px 12px;
    white-space: normal;
  }

  .page-about .about-rail .rail-index__link::before {
    content: "";
    position: absolute;
    left: -19px;
    top: 50%;
    width: 9px;
    height: 9px;
    margin-top: -4.5px;
    border-radius: 50%;
    background: var(--deep);
    border: 2px solid var(--steel);
    transition: background 0.25s var(--ease), border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
  }

  .page-about .about-rail .rail-index__link:hover::before {
    border-color: var(--orange);
  }

  .page-about .about-rail .rail-index__link[aria-current="true"] {
    color: var(--orange);
    background: rgba(255, 106, 31, 0.1);
    border-color: transparent;
  }

  .page-about .about-rail .rail-index__link[aria-current="true"]::before {
    background: var(--orange);
    border-color: var(--orange);
    box-shadow: 0 0 0 4px rgba(255, 106, 31, 0.18);
  }

  .page-about .about-text {
    max-width: 62ch;
  }

  .page-about .about-hero::before {
    right: -6%;
    width: min(820px, 62%);
  }
}
<<<END>>>