.page-about {
  --about-rail-w: 224px;
  background: var(--mist);
  color: var(--ink);
  font-family: var(--font-sans);
}

/* ── 首屏 ─────────────────────────────── */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(22px, 3.5vw, 40px) 0 clamp(52px, 7vw, 92px);
  background: linear-gradient(165deg, var(--mist) 0%, var(--mist) 56%, var(--xue-pale) 56.2%, var(--xue-pale) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: -80px;
  bottom: -140px;
  width: 340px;
  height: 340px;
  border-radius: 50%;
  background: radial-gradient(circle at 32% 32%, rgba(201, 154, 61, 0.18), rgba(201, 154, 61, 0) 70%);
  pointer-events: none;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 48px);
  margin-top: clamp(16px, 2.4vw, 30px);
  align-items: end;
}

.page-about .about-hero__tag {
  margin: 0;
}

.page-about .about-hero h1 {
  margin: 14px 0 0;
  font-size: clamp(34px, 5.6vw, 60px);
  line-height: 1.14;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--xue-deep);
  max-width: 15em;
}

.page-about .about-hero__lede {
  margin: 20px 0 0;
  font-size: clamp(16px, 1.7vw, 18px);
  line-height: 1.85;
  color: var(--ink);
  max-width: 34em;
}

.page-about .about-hero__meta {
  margin: 22px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--graphite);
}

.page-about .about-hero__note {
  display: none;
  position: absolute;
  right: clamp(10px, 2vw, 26px);
  top: 46%;
  transform: translateY(-50%);
  writing-mode: vertical-rl;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.34em;
  color: var(--xue);
  opacity: 0.55;
}

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

.page-about .figure__frame {
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: var(--canvas);
}

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

.page-about .about-hero__figure .figure__frame {
  border-radius: var(--radius-xl);
}

/* ── 双栏骨架 ─────────────────────────── */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(30px, 4vw, 48px);
  padding-top: clamp(44px, 6vw, 76px);
  padding-bottom: clamp(56px, 8vw, 104px);
}

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

/* ── 章节索引 ─────────────────────────── */
.page-about .rail {
  position: static;
}

.page-about .rail__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--grape);
}

.page-about .rail__list {
  display: flex;
  flex-direction: row;
  gap: 18px;
  margin: 0;
  padding: 12px 0 0;
  list-style: none;
  border-top: 1px solid var(--line);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .rail__link {
  display: block;
  white-space: nowrap;
  padding: 4px 0;
  font-size: 14px;
  line-height: 1.5;
  color: var(--graphite);
  text-decoration: none;
  transition: color 200ms var(--ease);
}

.page-about .rail__link:hover {
  color: var(--xue-deep);
}

.page-about .rail__link.is-active {
  color: var(--xue-deep);
  font-weight: 700;
}

/* ── 章节 ─────────────────────────────── */
.page-about .chapter {
  scroll-margin-top: 120px;
  padding: clamp(36px, 5vw, 66px) 0;
  border-top: 1px solid var(--line);
}

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

.page-about .chapter__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  margin-bottom: clamp(16px, 2.4vw, 24px);
}

.page-about .chapter__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--grape);
  padding: 3px 10px;
  border-radius: var(--pill);
  background: var(--grape-pale);
}

.page-about .chapter__title {
  margin: 0;
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1.25;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--xue-deep);
}

.page-about .chapter__lede,
.page-about .chapter__p {
  max-width: 44em;
  font-size: 17px;
  line-height: 1.85;
  color: var(--ink);
  margin: 0 0 18px;
}

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

.page-about .num {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 1.05em;
  color: var(--xue-deep);
}

/* ── 服务对象 ─────────────────────────── */
.page-about .roles {
  list-style: none;
  margin: 26px 0;
  padding: 0;
  display: grid;
  gap: 20px;
}

.page-about .roles__item {
  padding-left: 18px;
  border-left: 3px solid var(--xue-pale);
}

.page-about .roles__name {
  margin: 0 0 6px;
  font-size: 18px;
  font-weight: 700;
  color: var(--xue-deep);
}

.page-about .roles__text {
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--graphite);
  max-width: 44em;
}

/* ── 规模配图 ─────────────────────────── */
.page-about .about-scale {
  margin-top: clamp(26px, 4vw, 40px);
}

/* ── 团队分工 ─────────────────────────── */
.page-about .teams {
  list-style: none;
  margin: 26px 0;
  padding: 0;
}

.page-about .team {
  padding: 16px 0;
  border-bottom: 1px dashed var(--line);
}

.page-about .team:first-child {
  border-top: 1px dashed var(--line);
}

.page-about .team__row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin: 0;
}

.page-about .team__name {
  display: inline-block;
  padding: 5px 16px;
  border-radius: var(--pill);
  background: var(--xue-pale);
  color: var(--xue-deep);
  font-size: 15px;
  font-weight: 700;
}

.page-about .team__num {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 600;
  color: var(--gold-ink);
}

.page-about .team__unit {
  font-size: 12px;
  margin-left: 3px;
}

.page-about .team__desc {
  margin: 8px 0 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--graphite);
  max-width: 42em;
}

/* ── 年表 ─────────────────────────────── */
.page-about .chrono {
  position: relative;
  list-style: none;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 0 0 0 30px;
}

.page-about .chrono::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 10px;
  bottom: 16px;
  border-left: 1px dashed var(--line);
}

.page-about .chrono__item {
  position: relative;
  padding: 0 0 28px;
  outline: none;
}

.page-about .chrono__item::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 6px;
  width: 14px;
  height: 14px;
  box-sizing: border-box;
  border-radius: 50%;
  background: var(--canvas);
  border: 2px solid var(--line);
  transition: background 240ms var(--ease), border-color 240ms var(--ease);
}

.page-about .chrono__item:hover::before,
.page-about .chrono__item:focus-within::before {
  background: var(--xue);
  border-color: var(--xue);
}

.page-about .chrono__item--now::before {
  background: var(--gold);
  border-color: var(--gold-dark);
}

.page-about .chrono__stage {
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--grape);
}

.page-about .chrono__title {
  margin: 0 0 6px;
  font-size: 20px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .chrono__text {
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--graphite);
  max-width: 44em;
}

.page-about .chrono__more {
  display: grid;
  grid-template-rows: 0fr;
  opacity: 0;
  transition: grid-template-rows 340ms var(--ease), opacity 240ms var(--ease);
}

.page-about .chrono__more > div {
  overflow: hidden;
}

.page-about .chrono__more-text {
  margin: 10px 0 0;
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--gold);
  background: var(--gold-pale);
  color: var(--gold-ink);
  font-size: 15px;
  line-height: 1.7;
}

.page-about .chrono__item:hover .chrono__more,
.page-about .chrono__item:focus-within .chrono__more {
  grid-template-rows: 1fr;
  opacity: 1;
}

.page-about .about-chrono-figure {
  margin-top: clamp(20px, 3vw, 32px);
}

/* ── 三项约定 ─────────────────────────── */
.page-about .promise {
  display: grid;
  gap: 22px;
  margin-top: 22px;
}

.page-about .promise__item {
  padding: 20px 22px;
  border-radius: var(--radius-lg);
  background: var(--canvas);
}

.page-about .promise__item:nth-child(2) {
  background: var(--xue-pale);
}

.page-about .promise__item:nth-child(3) {
  background: var(--grape-pale);
}

.page-about .promise__label {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 700;
  color: var(--xue-deep);
}

.page-about .promise__item:nth-child(3) .promise__label {
  color: var(--grape);
}

.page-about .promise__text {
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink);
  max-width: 42em;
}

/* ── 资质与认可 ───────────────────────── */
.page-about .credits {
  list-style: none;
  margin: 22px 0 26px;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .credits__item {
  padding-left: 18px;
  border-left: 3px solid var(--grape-pale);
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink);
  max-width: 44em;
}

/* ── 页尾指路 ─────────────────────────── */
.page-about .about-next {
  margin-top: clamp(36px, 5vw, 56px);
  padding: clamp(22px, 3vw, 32px);
}

.page-about .about-next__text {
  margin: 0 0 18px;
  font-size: 17px;
  line-height: 1.8;
  color: var(--ink);
}

.page-about .about-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ── 响应式 ───────────────────────────── */
@media (min-width: 640px) {
  .page-about .chapter__lede::first-letter {
    float: left;
    font-size: 3.05em;
    line-height: 0.92;
    font-weight: 900;
    color: var(--xue);
    margin: 0.06em 0.14em 0 0;
  }

  .page-about .roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px 26px;
  }

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

  .page-about .promise__item:nth-child(3) {
    grid-column: 1 / -1;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 6.2fr) minmax(0, 5fr);
  }

  .page-about .about-scale .figure__frame,
  .page-about .about-chrono-figure .figure__frame {
    max-height: 420px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(44px, 6vw, 88px);
  }

  .page-about .rail {
    position: sticky;
    top: 108px;
    align-self: start;
  }

  .page-about .rail__list {
    flex-direction: column;
    gap: 2px;
    padding: 0 0 0 16px;
    border-top: 0;
    border-left: 1px solid var(--grape-pale);
    overflow-x: visible;
  }

  .page-about .rail__link {
    white-space: normal;
    font-size: 14px;
    line-height: 1.5;
    padding: 6px 0;
  }

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

  .page-about .promise__item:nth-child(3) {
    grid-column: auto;
  }
}

@media (min-width: 1280px) {
  .page-about .about-hero__note {
    display: block;
  }
}

@media (max-width: 899px) {
  .page-about .chrono__more {
    grid-template-rows: 1fr;
    opacity: 1;
  }

  .page-about .about-scale .figure__frame,
  .page-about .about-chrono-figure .figure__frame {
    border-radius: var(--radius-md);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .chrono__more,
  .page-about .chrono__item::before,
  .page-about .rail__link {
    transition: none;
  }

  .page-about .about-hero::after {
    display: none;
  }
}
<<<END>>>