.page-about {
  --about-rail: 232px;
  --about-gap: 64px;
  --about-glass: rgba(242, 245, 248, 0.05);
  --about-glass-hover: rgba(242, 245, 248, 0.11);
  --about-ink: rgba(242, 245, 248, 0.78);
  --about-ink-soft: rgba(242, 245, 248, 0.66);
  display: block;
  color: var(--snow);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 22px 0 0;
  font-size: var(--fs-13);
  letter-spacing: 0.04em;
  color: var(--rock);
}

.page-about .about-crumb a {
  display: inline-flex;
  align-items: center;
  min-height: 24px;
  color: var(--rock);
  text-decoration: none;
  transition: color var(--t-fast);
}

.page-about .about-crumb a:hover,
.page-about .about-crumb a:focus-visible {
  color: var(--gold);
}

.page-about .about-crumb [aria-current="page"] {
  color: var(--snow);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 32px 0 56px;
  background:
    radial-gradient(90% 70% at 86% 2%, rgba(227, 169, 60, 0.15), transparent 62%),
    linear-gradient(118deg, rgba(20, 44, 78, 0.9) 0%, rgba(11, 27, 51, 0) 60%);
}

.page-about .about-hero__grid {
  display: grid;
  gap: 32px;
}

.page-about .about-hero__copy .eyebrow {
  display: block;
  margin: 0 0 14px;
}

.page-about .about-hero__copy h1 {
  max-width: 18ch;
  margin: 0 0 20px;
  font-family: var(--f-display);
  font-size: var(--fs-40);
  font-weight: 700;
  line-height: 1.24;
  letter-spacing: 0.03em;
  color: var(--snow);
}

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

.page-about .about-hero__sub {
  max-width: 42ch;
  margin: 0 0 26px;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--about-ink-soft);
}

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

.page-about .about-hero__visual {
  position: relative;
  margin: 0;
}

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

/* ---------- 数据条 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 40px 0 0;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.page-about .about-stats__cell {
  padding: 16px 14px 18px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-stats__label {
  margin: 0 0 8px;
  font-size: var(--fs-13);
  letter-spacing: 0.1em;
  color: var(--rock);
}

.page-about .about-stats__value {
  margin: 0;
  font-size: var(--fs-24);
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--gold);
}

/* ---------- 页面骨架 ---------- */
.page-about .about-shell {
  display: grid;
  gap: 40px;
  padding-top: 48px;
  padding-bottom: 88px;
}

/* ---------- 左侧索引 ---------- */
.page-about .about-rail__title {
  margin: 0 0 12px;
  font-size: var(--fs-13);
  letter-spacing: 0.16em;
  color: var(--rock);
}

.page-about .about-rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--line);
}

.page-about .about-rail__link {
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: 44px;
  margin-left: -1px;
  padding: 8px 12px;
  font-size: var(--fs-14);
  color: var(--rock);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color var(--t-fast), border-color var(--t-fast), background-color var(--t-fast);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--snow);
  border-left-color: var(--orange);
  background: var(--about-glass);
}

.page-about .about-rail__idx {
  font-size: var(--fs-13);
  color: var(--clay);
  letter-spacing: 0.08em;
}

.page-about .about-rail__foot {
  margin: 20px 0 0;
  font-size: var(--fs-13);
}

.page-about .about-rail__foot a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--gold);
  text-decoration: none;
  border-bottom: 1px solid rgba(227, 169, 60, 0.35);
  transition: color var(--t-fast), border-color var(--t-fast);
}

.page-about .about-rail__foot a:hover,
.page-about .about-rail__foot a:focus-visible {
  color: var(--orange);
  border-color: var(--orange);
}

/* ---------- 章节通用 ---------- */
.page-about .chapter {
  position: relative;
  padding-top: 28px;
  margin-bottom: 72px;
}

.page-about .chapter::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background-image: repeating-linear-gradient(90deg, var(--clay) 0 2px, transparent 2px 14px);
  opacity: 0.7;
}

.page-about .chapter__num {
  margin: 0 0 10px;
  font-size: var(--fs-13);
  letter-spacing: 0.2em;
  color: var(--gold);
}

.page-about .chapter__title {
  margin: 0 0 16px;
  font-family: var(--f-display);
  font-size: var(--fs-24);
  font-weight: 700;
  line-height: 1.34;
  letter-spacing: 0.025em;
  color: var(--snow);
}

.page-about .chapter__lead {
  max-width: 58ch;
  margin: 0 0 30px;
  font-size: var(--fs-16);
  line-height: 1.8;
  color: var(--about-ink);
}

.page-about .chapter__figure {
  margin: 32px 0 0;
}

.page-about .chapter__figure--band {
  margin: 0 0 32px;
}

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

.page-about .chapter__caption {
  margin-top: 12px;
  font-size: var(--fs-13);
  line-height: 1.75;
  color: var(--rock);
}

/* ---------- 分工卡片 ---------- */
.page-about .duty-grid {
  display: grid;
  gap: 18px;
}

.page-about .duty {
  padding: 22px 20px 24px;
  background: var(--about-glass);
  border: 1px solid var(--line);
  border-top-width: 2px;
  border-radius: var(--radius);
  transition: transform var(--t-fast), background-color var(--t-fast), border-color var(--t-fast);
}

.page-about .duty--gold { border-top-color: var(--gold); }
.page-about .duty--moss { border-top-color: var(--moss); }
.page-about .duty--clay { border-top-color: var(--clay); }

.page-about .duty:hover {
  transform: translateY(-4px);
  background: var(--about-glass-hover);
  border-color: var(--line-strong);
}

.page-about .duty__count {
  margin: 0 0 6px;
  font-size: var(--fs-32);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--gold);
}

.page-about .duty--moss .duty__count { color: #7FB995; }
.page-about .duty--clay .duty__count { color: #C97A55; }

.page-about .duty__name {
  margin: 0 0 10px;
  font-family: var(--f-display);
  font-size: var(--fs-18);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--snow);
}

.page-about .duty__text {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--about-ink-soft);
}

/* ---------- 时间线 ---------- */
.page-about .timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 6px 0 0;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 14px;
  bottom: 24px;
  width: 1px;
  background: linear-gradient(180deg, var(--gold) 0%, var(--orange) 48%, var(--clay) 100%);
  opacity: 0.6;
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 32px 36px;
}

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

.page-about .timeline__dot {
  position: absolute;
  left: 0;
  top: 6px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--gold);
  box-shadow: 0 0 0 4px var(--night);
  transition: box-shadow var(--t-fast), background-color var(--t-fast);
}

.page-about .timeline__item:hover .timeline__dot,
.page-about .timeline__item:focus-within .timeline__dot {
  background: var(--orange);
  box-shadow: 0 0 0 4px var(--night), 0 0 0 6px rgba(241, 128, 74, 0.4);
}

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

.page-about .timeline__title {
  margin: 0 0 10px;
  font-family: var(--f-display);
  font-size: var(--fs-18);
  font-weight: 700;
  line-height: 1.5;
  letter-spacing: 0.02em;
  color: var(--snow);
}

.page-about .timeline__text {
  max-width: 56ch;
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--about-ink-soft);
}

.page-about .timeline__note {
  max-width: 56ch;
  margin: 0;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  font-size: var(--fs-13);
  line-height: 1.8;
  color: var(--gold);
  transition: max-height var(--t-base), opacity var(--t-base), margin-top var(--t-base);
}

.page-about .timeline__item:hover .timeline__note,
.page-about .timeline__item:focus-within .timeline__note {
  max-height: 140px;
  opacity: 1;
  margin-top: 10px;
}

/* ---------- 覆盖网格 ---------- */
.page-about .coverage-grid {
  display: grid;
  gap: 1px;
  margin: 0;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .coverage-grid__item {
  padding: 20px 18px 22px;
  background: var(--deep);
}

.page-about .coverage-grid__term {
  margin: 0 0 10px;
  font-size: var(--fs-13);
  letter-spacing: 0.12em;
  color: var(--rock);
}

.page-about .coverage-grid__value {
  margin: 0 0 10px;
  font-size: var(--fs-14);
  letter-spacing: 0.04em;
  color: var(--snow);
}

.page-about .coverage-grid__num {
  font-size: var(--fs-32);
  font-weight: 600;
  color: var(--gold);
  margin-right: 4px;
}

.page-about .coverage-grid__desc {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--about-ink-soft);
}

/* ---------- 资质区块 ---------- */
.page-about .credentials {
  position: relative;
  margin-bottom: 80px;
  padding: 30px 22px 34px;
  background: var(--rice);
  color: var(--night);
  border-radius: var(--radius);
}

.page-about .credentials::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--gold) 0%, var(--orange) 46%, var(--clay) 100%);
}

.page-about .credentials .chapter__num {
  color: var(--clay);
}

.page-about .credentials__title {
  margin: 0 0 14px;
  font-family: var(--f-display);
  font-size: var(--fs-24);
  font-weight: 700;
  line-height: 1.34;
  letter-spacing: 0.025em;
  color: var(--night);
}

.page-about .credentials__lead {
  max-width: 56ch;
  margin: 0;
  font-size: var(--fs-16);
  line-height: 1.8;
  color: rgba(11, 27, 51, 0.74);
}

.page-about .cred-grid {
  display: grid;
  gap: 14px;
  margin-top: 26px;
}

.page-about .cred-card {
  padding: 20px 18px 22px;
  background: rgba(255, 255, 255, 0.55);
  border: 1px solid rgba(11, 27, 51, 0.12);
  border-radius: var(--radius);
  backdrop-filter: blur(6px);
  transition: transform var(--t-fast), background-color var(--t-fast), border-color var(--t-fast);
}

.page-about .cred-card:hover {
  transform: translateY(-4px);
  background: rgba(255, 255, 255, 0.85);
  border-color: rgba(11, 27, 51, 0.24);
}

.page-about .cred-card__tag {
  margin: 0 0 10px;
  font-size: var(--fs-13);
  letter-spacing: 0.14em;
  color: var(--clay);
}

.page-about .cred-card__title {
  margin: 0 0 10px;
  font-family: var(--f-display);
  font-size: var(--fs-18);
  font-weight: 700;
  line-height: 1.5;
  letter-spacing: 0.02em;
  color: var(--night);
}

.page-about .cred-card__text {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: rgba(11, 27, 51, 0.72);
}

/* ---------- 取舍列表 ---------- */
.page-about .principle-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .principle {
  display: grid;
  gap: 8px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .principle__idx {
  font-size: var(--fs-13);
  letter-spacing: 0.18em;
  color: var(--gold);
}

.page-about .principle__title {
  margin: 0;
  font-family: var(--f-display);
  font-size: var(--fs-18);
  font-weight: 700;
  line-height: 1.5;
  letter-spacing: 0.02em;
  color: var(--snow);
}

.page-about .principle__text {
  margin: 0;
  max-width: 58ch;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--about-ink-soft);
}

/* ---------- 结尾行动区 ---------- */
.page-about .about-cta {
  display: grid;
  gap: 16px;
  padding: 28px 22px 32px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--gold);
  border-radius: var(--radius);
  background: linear-gradient(120deg, rgba(20, 44, 78, 0.95) 0%, rgba(11, 27, 51, 0.42) 100%);
}

.page-about .about-cta__title {
  margin: 0;
  font-family: var(--f-display);
  font-size: var(--fs-24);
  font-weight: 700;
  letter-spacing: 0.025em;
  color: var(--snow);
}

.page-about .about-cta__text {
  margin: 0;
  max-width: 56ch;
  font-size: var(--fs-16);
  line-height: 1.8;
  color: var(--about-ink);
}

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

/* ---------- 焦点可见性 ---------- */
.page-about a:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 2px;
}

/* ---------- 中等屏 ---------- */
@media (min-width: 700px) {
  .page-about .about-hero {
    padding: 44px 0 68px;
  }

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

  .page-about .about-stats__cell {
    padding: 20px 20px 22px;
  }

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

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

  .page-about .cred-card:hover {
    transform: translateY(-4px);
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 1000px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    gap: 56px;
    align-items: center;
  }

  .page-about .about-hero__copy h1 {
    max-width: 15ch;
    font-size: var(--fs-56);
  }

  .page-about .about-hero__visual::after {
    content: "";
    position: absolute;
    right: -18px;
    bottom: -18px;
    width: 96px;
    height: 96px;
    border-right: 2px solid var(--gold);
    border-bottom: 2px solid var(--gold);
    opacity: 0.55;
    pointer-events: none;
  }

  .page-about .about-shell {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
    padding-top: 64px;
    padding-bottom: 112px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h-sm) + 28px);
  }

  .page-about .chapter {
    padding-top: 34px;
    margin-bottom: 96px;
  }

  .page-about .chapter__title {
    font-size: var(--fs-32);
  }

  .page-about .duty-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
    gap: 20px;
  }

  .page-about .duty:nth-child(2) {
    margin-top: 32px;
  }

  .page-about .duty:nth-child(3) {
    margin-top: 64px;
  }

  .page-about .credentials {
    margin-bottom: 104px;
    padding: 46px 44px 50px;
  }

  .page-about .principle {
    grid-template-columns: 56px minmax(0, 220px) minmax(0, 1fr);
    align-items: baseline;
    gap: 0 24px;
    padding: 26px 0;
  }

  .page-about .about-cta {
    padding: 40px 44px 44px;
  }
}

/* ---------- 触屏设备：时间线补充说明保持展开 ---------- */
@media (hover: none) {
  .page-about .timeline__note {
    max-height: none;
    opacity: 1;
    margin-top: 10px;
  }
}

/* ---------- 减少动态偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .duty,
  .page-about .cred-card,
  .page-about .timeline__note,
  .page-about .timeline__dot,
  .page-about .about-rail__link {
    transition-duration: 1ms;
  }

  .page-about .duty:hover,
  .page-about .cred-card:hover {
    transform: none;
  }
}