.page-about {
  --tl-line: rgba(47, 74, 62, 0.9);
  --tl-node-bg: var(--ink);
  --about-gap: 1px;
  display: block;
  overflow-x: hidden;
}

/* ===== 首屏 ===== */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: 10px 0 42px;
  border-bottom: var(--hair);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -34%;
  right: -20%;
  width: 70%;
  height: 176%;
  background: rgba(56, 242, 198, 0.055);
  clip-path: polygon(40% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
  z-index: 0;
}

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

.page-about .about-hero__title {
  margin: 14px 0 20px;
  font-size: clamp(28px, 6.6vw, 58px);
  line-height: 1.16;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-hero__lead {
  margin: 0 0 26px;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--silver);
}

.page-about .about-hero__meta {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
  font-size: 13px;
  color: var(--stone);
}

.page-about .about-hero__meta li {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
}

.page-about .about-hero__meta .mono {
  font-size: 14px;
  color: var(--cyan);
}

/* ===== 章节索引 ===== */
.page-about .about-index {
  background: var(--deep);
  border-bottom: var(--hair);
}

.page-about .about-index__inner {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-top: 18px;
  padding-bottom: 18px;
}

.page-about .about-index__label {
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--clay);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
}

.page-about .about-index__list a {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  font-size: 13px;
  color: var(--stone);
  text-decoration: none;
  padding-bottom: 3px;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .about-index__list a .mono {
  color: var(--moss);
  transition: color 0.2s var(--ease);
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--cyan);
}

.page-about .about-index__list a:hover .mono,
.page-about .about-index__list a:focus-visible .mono {
  color: var(--cyan);
}

/* ===== 时间轴 ===== */
.page-about .timeline {
  list-style: none;
  position: relative;
  margin: 34px 0 0;
  padding: 0;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 44px;
  width: 1px;
  background: var(--tl-line);
}

.page-about .timeline-item {
  position: relative;
  padding-left: 38px;
  padding-bottom: 44px;
}

.page-about .timeline-item:last-child {
  padding-bottom: 6px;
}

.page-about .timeline-item::before {
  content: "";
  position: absolute;
  left: 1px;
  top: 7px;
  width: 9px;
  height: 9px;
  background: var(--tl-node-bg);
  border: 1px solid var(--cyan);
  transform: rotate(45deg);
}

.page-about .timeline-year {
  display: block;
  margin-bottom: 7px;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.page-about .timeline-title {
  margin: 0 0 10px;
  font-size: 19px;
  line-height: 1.45;
  font-weight: 600;
  color: var(--paper);
}

.page-about .timeline-text {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.82;
  color: var(--silver);
}

.page-about .timeline-item--narrow .timeline-text {
  max-width: 46ch;
}

.page-about .timeline-item--wide .timeline-text {
  max-width: 72ch;
}

.page-about .timeline-figure {
  margin: 20px 0 0;
  max-width: 560px;
}

.page-about .timeline-figure .figure-caption {
  margin-top: 8px;
  font-size: 12px;
  color: var(--stone);
}

/* ===== 团队 ===== */
.page-about .team-figure {
  margin: 0 0 34px;
}

.page-about .team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  margin-top: 30px;
  border: var(--hair);
  background: var(--moss);
}

.page-about .team-card {
  position: relative;
  background: var(--deep);
  padding: 28px 22px 30px;
}

.page-about .team-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  height: 2px;
  width: var(--bar, 40%);
  background: var(--cyan);
}

.page-about .team-card:nth-child(1) { --bar: 62%; }
.page-about .team-card:nth-child(2) { --bar: 36%; }
.page-about .team-card:nth-child(3) { --bar: 24%; }

.page-about .team-card-title {
  margin: 8px 0 10px;
  font-size: 17px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .team-card-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.82;
  color: var(--silver);
}

.page-about .team-card-note {
  display: block;
  margin-top: 16px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--stone);
}

/* ===== 覆盖范围数据条 ===== */
.page-about .about-coverage {
  position: relative;
  background: var(--charcoal);
  padding: 44px 0 48px;
  margin: 8px 0;
}

.page-about .about-coverage::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--cyan) 0%, rgba(56, 242, 198, 0) 78%);
}

.page-about .coverage-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--about-gap);
  margin-top: 24px;
  border: var(--hair);
  background: var(--moss);
}

.page-about .coverage-cell {
  background: var(--charcoal);
  padding: 22px 18px 24px;
  transition: background 0.25s var(--ease);
}

.page-about .coverage-cell:hover {
  background: var(--deep);
}

.page-about .coverage-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 34px;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.page-about .coverage-label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--silver);
}

.page-about .coverage-sub {
  display: block;
  margin-top: 7px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--stone);
}

/* ===== 服务对象 ===== */
.page-about .audience-list {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  border-top: var(--hair);
}

.page-about .audience-item {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 14px;
  padding: 22px 0;
  border-bottom: var(--hair);
}

.page-about .audience-num {
  padding-top: 3px;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--clay);
}

.page-about .audience-title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .audience-text {
  margin: 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.82;
  color: var(--silver);
}

/* ===== 协作方式 ===== */
.page-about .partner-grid {
  display: grid;
  grid-template-columns: 1fr;
  margin-top: 30px;
  border-top: var(--hair);
}

.page-about .partner-item {
  padding: 24px 0;
  border-bottom: var(--hair);
}

.page-about .partner-item h3 {
  margin: 0 0 9px;
  font-size: 16px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .partner-item p {
  margin: 0;
  max-width: 56ch;
  font-size: 14px;
  line-height: 1.82;
  color: var(--silver);
}

/* ===== 上海基点 ===== */
.page-about .about-base {
  position: relative;
  overflow: hidden;
  margin-top: 8px;
  padding: 56px 0 60px;
  background: var(--charcoal);
}

.page-about .about-base__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.3;
  filter: grayscale(0.5) brightness(0.55);
}

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

.page-about .about-base__title {
  margin: 12px 0 16px;
  font-size: clamp(24px, 4.6vw, 36px);
  line-height: 1.28;
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-base__lead {
  margin: 0 0 32px;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--silver);
}

.page-about .glossary {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  margin: 0;
  border: var(--hair);
  background: rgba(47, 74, 62, 0.85);
}

.page-about .glossary-term {
  background: rgba(3, 10, 8, 0.84);
  padding: 20px 18px 22px;
}

.page-about .glossary-term dt {
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.page-about .glossary-term dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.82;
  color: var(--silver);
}

/* ===== 收尾 ===== */
.page-about .about-next__inner {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.page-about .about-next__title {
  margin: 0;
  font-size: 22px;
  line-height: 1.4;
  font-weight: 600;
  color: var(--paper);
}

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

.page-about .about-footnote {
  margin: 0 0 40px;
  padding-top: 18px;
  border-top: var(--hair);
  font-size: 12px;
  line-height: 1.8;
  color: var(--stone);
}

/* ===== 媒体查询 ===== */
@media (min-width: 760px) {
  .page-about .about-index__inner {
    flex-direction: row;
    align-items: center;
    gap: 28px;
  }

  .page-about .timeline-item {
    padding-left: 52px;
    padding-bottom: 52px;
  }

  .page-about .timeline::before {
    left: 6px;
  }

  .page-about .timeline-item::before {
    left: 2px;
  }

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

  .page-about .audience-item {
    grid-template-columns: 116px 1fr;
    gap: 32px;
    padding: 28px 0;
  }

  .page-about .partner-grid {
    grid-template-columns: 1fr 1fr;
    column-gap: 56px;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 16px 0 54px;
  }

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

  .page-about .about-next__inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }

  .page-about .about-next__links {
    flex-wrap: nowrap;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__list a,
  .page-about .coverage-cell {
    transition: none;
  }
}
</style>