.page-about {
  --about-rule: 1px solid var(--grid);
  --about-dash: 1px dashed var(--grid);
  background: var(--ink);
  color: var(--text);
  font-family: var(--sans);
  padding-bottom: clamp(56px, 9vw, 132px);
  overflow-x: clip;
}

.page-about .breadcrumb {
  padding-top: clamp(20px, 3vw, 34px);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--muted);
}

.page-about .breadcrumb a {
  color: var(--muted);
  text-decoration: none;
  transition: color .18s var(--ease);
}

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

/* ---------- 封面 ---------- */
.page-about .about-cover {
  padding-block: clamp(26px, 4.8vw, 60px) clamp(26px, 4vw, 46px);
  border-bottom: var(--about-rule);
}

.page-about .about-cover .eyebrow {
  margin: 0 0 clamp(14px, 2vw, 22px);
}

.page-about .cover-grid {
  display: grid;
  gap: clamp(20px, 3vw, 40px);
}

.page-about .about-cover h1 {
  margin: 0;
  font-size: clamp(36px, 7.2vw, 76px);
  line-height: .94;
  letter-spacing: -.02em;
  font-weight: 900;
  color: var(--paper);
}

.page-about .cover-lead p {
  margin: 0 0 clamp(18px, 2.4vw, 26px);
  font-size: 16px;
  line-height: 1.78;
  max-width: 34em;
}

.page-about .cover-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px 18px;
}

.page-about .cover-facts li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  border-top: var(--about-rule);
  padding-top: 10px;
}

.page-about .cover-facts .num {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-size: 20px;
  color: var(--amber);
}

.page-about .cover-facts span:last-child {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--muted);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-shell {
  padding-top: clamp(32px, 5vw, 64px);
  display: grid;
  gap: clamp(24px, 4vw, 44px);
  align-items: start;
}

.page-about .about-index {
  align-self: start;
}

.page-about .index-title {
  margin: 0 0 10px;
}

.page-about .index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.page-about .index-list a {
  display: block;
  padding: 6px 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--muted);
  text-decoration: none;
  border: 1px solid transparent;
  transition: color .18s var(--ease), border-color .18s var(--ease), background .18s var(--ease);
}

.page-about .index-list a:hover,
.page-about .index-list a:focus-visible {
  color: var(--cyan);
  border-color: var(--cyan);
  background: var(--den);
}

/* ---------- 章节 ---------- */
.page-about .about-section {
  padding-block: clamp(34px, 5.5vw, 58px);
  border-top: var(--about-rule);
}

.page-about .about-section:first-of-type {
  border-top: 0;
  padding-top: 0;
}

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

.page-about .section-head .idx {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--cyan);
}

.page-about .section-head h2 {
  margin: 0;
  font-size: clamp(24px, 3.4vw, 38px);
  line-height: 1.08;
  letter-spacing: -.02em;
  font-weight: 800;
  color: var(--paper);
}

.page-about .about-section p {
  margin: 0 0 14px;
  line-height: 1.78;
  max-width: 42em;
  overflow-wrap: anywhere;
}

.page-about .about-lead {
  font-size: 17px;
  color: var(--mist);
  max-width: 38em;
}

.page-about .about-section a {
  color: var(--cyan);
  text-underline-offset: 3px;
}

.page-about .about-prose {
  max-width: 42em;
}

.page-about .about-cols {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
  align-items: start;
  margin-top: clamp(16px, 2.4vw, 26px);
}

.page-about .about-cols--tight {
  margin-top: clamp(26px, 4vw, 44px);
}

/* ---------- 图片 ---------- */
.page-about .about-fig {
  margin: 0;
  border: var(--about-rule);
  background: var(--den);
}

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

.page-about .about-fig figcaption {
  margin: 0;
  padding: 10px 12px;
  border-top: var(--about-rule);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--muted);
}

/* ---------- 流程 ---------- */
.page-about .flow {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: var(--about-rule);
}

.page-about .flow-step {
  background: var(--den);
  padding: clamp(18px, 2.6vw, 26px);
}

.page-about .flow-step .flow-no {
  display: block;
  margin-bottom: 10px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--amber);
}

.page-about .flow-step p {
  max-width: 30em;
}

.page-about .about-section h3 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--mist);
}

/* ---------- 三个小组 ---------- */
.page-about .crew {
  margin-top: clamp(20px, 3vw, 28px);
  border-top: var(--about-dash);
}

.page-about .crew-row {
  display: grid;
  gap: 8px;
  padding: clamp(18px, 2.6vw, 26px) 0;
  border-bottom: var(--about-dash);
}

.page-about .crew .crew-name {
  margin: 0;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-about .crew .crew-name span {
  display: block;
  margin-top: 7px;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: .1em;
  color: var(--cyan);
}

.page-about .crew .crew-detail p {
  margin: 0;
}

/* ---------- 改版对比 ---------- */
.page-about .shift {
  display: grid;
  gap: 1px;
  margin: clamp(20px, 3vw, 28px) 0;
  background: var(--grid);
  border: var(--about-rule);
}

.page-about .shift-cell {
  background: var(--den);
  padding: clamp(18px, 2.4vw, 24px);
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .shift-cell .num {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1;
  color: var(--amber);
}

.page-about .shift-cell span:last-child {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--muted);
}

/* ---------- 节奏表 ---------- */
.page-about .rhythm {
  margin: clamp(18px, 2.6vw, 26px) 0 0;
  border-top: var(--about-rule);
}

.page-about .rhythm-row {
  display: grid;
  gap: 6px;
  padding: clamp(14px, 2vw, 18px) 0;
  border-bottom: var(--about-rule);
}

.page-about .rhythm-row dt {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--amber);
}

.page-about .rhythm-row dd {
  margin: 0;
  line-height: 1.78;
  max-width: 40em;
}

/* ---------- 时间线 ---------- */
.page-about .tl {
  list-style: none;
  position: relative;
  margin: clamp(24px, 3.5vw, 36px) 0 0;
  padding: 0 0 0 28px;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 14px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), var(--grid) 74%);
}

.page-about .tl-item {
  position: relative;
  padding-bottom: clamp(22px, 3vw, 30px);
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: -25px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--cyan);
  transition: background .2s var(--ease), box-shadow .2s var(--ease);
}

.page-about .tl-item:hover::before,
.page-about .tl-item:focus::before,
.page-about .tl-item:focus-within::before {
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(53, 242, 201, .16);
}

.page-about .tl-year {
  display: block;
  margin-bottom: 6px;
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  letter-spacing: .12em;
  color: var(--amber);
}

.page-about .tl-item h3 {
  margin: 0 0 4px;
  font-size: 18px;
  color: var(--paper);
}

.page-about .tl-item p {
  margin: 0;
  max-width: 38em;
}

.page-about .tl-more {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: max-height .3s var(--ease), opacity .22s var(--ease), margin-top .3s var(--ease);
}

.page-about .tl-more p {
  font-size: 15px;
  color: var(--text);
}

.page-about .tl-item:hover .tl-more,
.page-about .tl-item:focus .tl-more,
.page-about .tl-item:focus-within .tl-more {
  max-height: 220px;
  opacity: 1;
  margin-top: 8px;
}

.page-about .about-fig--wide {
  margin-top: clamp(24px, 3.5vw, 40px);
}

/* ---------- 联系 ---------- */
.page-about .reach {
  list-style: none;
  margin: clamp(18px, 2.6vw, 26px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--grid);
  border: var(--about-rule);
}

.page-about .reach-item {
  background: var(--ink);
  padding: clamp(18px, 2.4vw, 26px);
}

.page-about .reach-item h3 {
  color: var(--paper);
  font-size: 16px;
}

.page-about .reach-item p {
  margin: 0;
  max-width: 40em;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .cover-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 720px) {
  .page-about .flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .rhythm-row {
    grid-template-columns: 140px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }
}

@media (min-width: 780px) {
  .page-about .crew-row {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: clamp(20px, 3vw, 40px);
  }
}

@media (min-width: 860px) {
  .page-about .about-cols {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  }

  .page-about .about-cols--tight {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  }
}

@media (min-width: 900px) {
  .page-about .cover-grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    align-items: end;
  }
}

@media (min-width: 1000px) {
  .page-about .about-shell {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: clamp(40px, 6vw, 88px);
  }

  .page-about .about-index {
    position: sticky;
    top: 104px;
  }

  .page-about .index-list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 0;
  }

  .page-about .index-list a {
    border: 0;
    border-left: 2px solid transparent;
    padding: 7px 0 7px 14px;
    background: transparent;
  }

  .page-about .index-list a:hover,
  .page-about .index-list a:focus-visible {
    background: transparent;
  }
}

/* 触屏设备不依赖悬停，时间线补充说明直接展开 */
@media (hover: none) {
  .page-about .tl-more {
    max-height: none;
    opacity: 1;
    margin-top: 8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .index-list a,
  .page-about .tl-item::before,
  .page-about .tl-more {
    transition: none;
  }

  .page-about .tl-more {
    max-height: none;
    opacity: 1;
    margin-top: 8px;
  }
}