.page-about {
  --about-rail-w: 196px;
  --about-gap: clamp(1.5rem, 3vw, 2.5rem);
  display: block;
}

.page-about .crumbs {
  padding: 1.15rem 0 1.35rem;
  display: flex;
  align-items: center;
  gap: .55rem;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--mist);
}

.page-about .crumbs__link {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.page-about .crumbs__link:hover,
.page-about .crumbs__link:focus-visible {
  color: var(--amber-bright);
  border-bottom-color: var(--amber);
}

.page-about .crumbs__item {
  color: var(--amber-bright);
}

.page-about .crumbs__item::before {
  content: "/";
  color: var(--line);
  margin-right: .55rem;
}

/* ---------- 左侧索引轴 ---------- */

.page-about .about-shell {
  display: block;
}

.page-about .about-rail {
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
  padding: .9rem 0 1rem;
  background: linear-gradient(180deg, rgba(16, 43, 63, .55), rgba(10, 26, 41, 0));
}

.page-about .index-rail__label {
  margin: 0 0 .6rem;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .14em;
  color: var(--mist);
}

.page-about .index-rail__list {
  display: flex;
  gap: 1.15rem;
  list-style: none;
  margin: 0;
  padding: 0 0 .2rem;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .index-rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .index-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: .45rem;
  white-space: nowrap;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--mist);
  text-decoration: none;
  padding: .3rem 0;
  border-bottom: 1px solid transparent;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.page-about .index-rail__link:hover,
.page-about .index-rail__link:focus-visible {
  color: var(--amber-bright);
  border-bottom-color: var(--amber);
}

.page-about .index-rail__num {
  color: var(--cinnabar-bright);
}

.page-about .about-bookmark {
  margin-top: 1rem;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  white-space: nowrap;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  display: grid;
  gap: 1.75rem;
  padding: clamp(1.9rem, 4vw, 3.4rem) 0 clamp(1.7rem, 3.4vw, 2.8rem);
}

.page-about .about-hero h1 {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(29px, 4.2vw, 52px);
  line-height: 1.14;
  letter-spacing: -.01em;
  color: var(--paper);
  margin: 0 0 1.1rem;
  max-width: 22ch;
}

.page-about .about-hero .lede {
  margin: 0;
  max-width: 60ch;
  font-size: clamp(15.5px, 1.45vw, 17px);
  line-height: 1.85;
  color: var(--paper-soft);
}

.page-about .about-hero__visual {
  border: 1px solid var(--line-soft);
  border-radius: var(--r-md);
  background: linear-gradient(155deg, rgba(16, 43, 63, .9), rgba(10, 26, 41, .35));
  padding: clamp(.9rem, 2vw, 1.4rem);
}

.page-about .about-hero__svg {
  display: block;
  width: 100%;
  height: auto;
}

/* ---------- 首屏数字条 ---------- */

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

.page-about .about-fact {
  background: var(--ink);
  padding: 1.05rem 1.1rem 1.2rem;
  display: flex;
  flex-direction: column;
  gap: .35rem;
}

.page-about .about-fact__num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.2vw, 34px);
  line-height: 1;
  color: var(--amber-bright);
  font-variant-numeric: tabular-nums;
}

.page-about .about-fact__label {
  font-size: 13px;
  line-height: 1.55;
  color: var(--mist);
}

/* ---------- 通用区块 ---------- */

.page-about .about-block {
  padding: clamp(2.4rem, 5vw, 4.2rem) 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-block--start {
  border-bottom: none;
}

.page-about .about-block__head {
  max-width: 48rem;
  margin-bottom: clamp(1.5rem, 3vw, 2.3rem);
}

.page-about .about-block__head h2 {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(22px, 2.6vw, 34px);
  line-height: 1.22;
  letter-spacing: -.01em;
  color: var(--paper);
  margin: 0 0 .85rem;
}

.page-about .about-block__head p {
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--paper-soft);
}

/* ---------- 三类服务 ---------- */

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

.page-about .scope-item {
  display: grid;
  grid-template-columns: 2.6rem minmax(0, 1fr);
  gap: 1rem;
  padding: 1.35rem 0;
  border-bottom: 1px solid var(--line-soft);
  transition: background .2s var(--ease);
}

.page-about .scope-item:hover {
  background: rgba(30, 67, 89, .18);
}

.page-about .scope-item__num {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--cinnabar-bright);
  padding-top: .2rem;
}

.page-about .scope-item__title {
  margin: 0 0 .45rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 19px;
  color: var(--paper);
}

.page-about .scope-item__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 图片块 ---------- */

.page-about .about-figure {
  margin: 2.2rem 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line-soft);
  border-radius: var(--r-sm);
  background: var(--slate);
  object-fit: cover;
}

.page-about .about-figure__cap {
  margin-top: .8rem;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: .02em;
  color: var(--mist);
}

/* ---------- 双栏对比 ---------- */

.page-about .fit-grid {
  border-top: 1px solid var(--line-soft);
}

.page-about .fit-col {
  padding: 1.4rem 0 1.6rem;
}

.page-about .fit-col + .fit-col {
  border-top: 1px solid var(--line-soft);
}

.page-about .fit-col__label {
  margin: 0 0 1rem;
  display: inline-flex;
  align-items: center;
}

.page-about .fit-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: .85rem;
}

.page-about .fit-list li {
  position: relative;
  padding-left: 1.35rem;
  font-size: 15px;
  line-height: 1.8;
  color: var(--paper-soft);
}

.page-about .fit-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .66em;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--celadon);
}

.page-about .fit-col--alt .fit-list li::before {
  background: var(--amber);
}

/* ---------- 版本时间轴 ---------- */

.page-about .timeline {
  display: flex;
  gap: 0;
  overflow-x: auto;
  padding: .5rem 0 .9rem;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

.page-about .timeline::-webkit-scrollbar {
  height: 6px;
}

.page-about .timeline::-webkit-scrollbar-thumb {
  background: var(--line);
  border-radius: 3px;
}

.page-about .tl-item {
  position: relative;
  flex: 0 0 min(17rem, 78vw);
  scroll-snap-align: start;
  border-top: 1px solid var(--line);
  padding: 1.6rem 1.35rem 1.4rem 0;
  margin-right: 1.35rem;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  top: -5px;
  left: 0;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 0 3px rgba(224, 163, 64, .14);
}

.page-about .tl-item--lts::before {
  background: var(--celadon);
  box-shadow: 0 0 0 3px rgba(71, 174, 147, .16);
}

.page-about .tl-item--now::before {
  background: var(--cinnabar-bright);
  box-shadow: 0 0 0 3px rgba(255, 113, 89, .16);
}

.page-about .tl-item__head {
  display: block;
  cursor: pointer;
  list-style: none;
  padding-right: .75rem;
}

.page-about .tl-item__head::-webkit-details-marker {
  display: none;
}

.page-about .tl-item__head:focus-visible {
  outline: 2px solid var(--celadon-bright);
  outline-offset: 4px;
  border-radius: var(--r-xs);
}

.page-about .tl-item__ver {
  display: block;
  font-family: var(--font-mono);
  font-size: 19px;
  letter-spacing: .04em;
  color: var(--amber-bright);
  font-variant-numeric: tabular-nums;
  margin-bottom: .3rem;
}

.page-about .tl-item--lts .tl-item__ver {
  color: var(--celadon-bright);
}

.page-about .tl-item--now .tl-item__ver {
  color: var(--cinnabar-bright);
}

.page-about .tl-item__name {
  display: block;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.35;
  color: var(--paper);
}

.page-about .tl-item__body {
  margin: .7rem 0 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 团队分工 ---------- */

.page-about .crew {
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: var(--r-sm);
  overflow: hidden;
}

.page-about .crew-line {
  background: var(--ink);
  padding: 1.3rem 1.2rem 1.5rem;
}

.page-about .crew-line__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--cinnabar-bright);
}

.page-about .crew-line__title {
  margin: .5rem 0 .6rem;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 18px;
  color: var(--paper);
}

.page-about .crew-line__headcount {
  font-family: var(--font-mono);
  font-size: 26px;
  color: var(--amber-bright);
  font-variant-numeric: tabular-nums;
  line-height: 1;
  margin-right: .3rem;
}

.page-about .crew-line__desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 表格 ---------- */

.page-about .about-table-wrap {
  margin-top: 1.8rem;
  border: 1px solid var(--line-soft);
  border-radius: var(--r-sm);
  overflow-x: auto;
}

.page-about .about-table-caption {
  caption-side: top;
  text-align: left;
  padding: .8rem 1rem;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--mist);
  background: rgba(16, 43, 63, .6);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-table-wrap .table {
  min-width: 34rem;
}

.page-about .about-table-wrap .table th {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--mist);
  text-align: left;
}

.page-about .about-table-wrap .table td {
  font-size: 14.5px;
  color: var(--paper-soft);
  vertical-align: middle;
}

/* ---------- 成果数字 ---------- */

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

.page-about .proof-cell {
  background: var(--ink);
  padding: 1.25rem 1.15rem 1.4rem;
  display: flex;
  flex-direction: column;
  gap: .3rem;
}

.page-about .proof-cell__num {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(30px, 4vw, 44px);
  line-height: 1;
  color: var(--amber-bright);
  font-variant-numeric: tabular-nums;
  letter-spacing: -.01em;
}

.page-about .proof-cell__unit {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--paper);
}

.page-about .proof-cell__note {
  margin: .35rem 0 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 入口卡片 ---------- */

.page-about .start-grid {
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: var(--r-sm);
  overflow: hidden;
}

.page-about .start-card {
  display: block;
  background: var(--slate);
  padding: 1.25rem 1.2rem 1.4rem;
  text-decoration: none;
  transition: background .2s var(--ease);
}

.page-about .start-card:hover,
.page-about .start-card:focus-visible {
  background: rgba(198, 64, 46, .18);
}

.page-about .start-card:focus-visible {
  outline: 2px solid var(--celadon-bright);
  outline-offset: -3px;
}

.page-about .start-card__label {
  display: block;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 18px;
  color: var(--amber-bright);
  margin-bottom: .45rem;
}

.page-about .start-card__desc {
  display: block;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--paper-soft);
}

/* ---------- 平板与桌面 ---------- */

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

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

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

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

@media (min-width: 820px) {
  .page-about .fit-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

  .page-about .fit-col {
    padding: 1.8rem 2rem 1.9rem 0;
  }

  .page-about .fit-col + .fit-col {
    border-top: none;
    border-left: 1px solid var(--line);
    padding-left: 2rem;
    padding-right: 0;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.28fr) minmax(0, .95fr);
    align-items: end;
    gap: clamp(2rem, 4vw, 3.6rem);
  }
}

@media (min-width: 1024px) {
  .page-about .about-shell {
    display: grid;
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 0 clamp(1.8rem, 3vw, 3rem);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 88px;
    border-top: none;
    border-bottom: none;
    border-right: 1px solid var(--line-soft);
    padding: 2.6rem 1.5rem 0 0;
    background: none;
  }

  .page-about .index-rail__list {
    flex-direction: column;
    gap: .1rem;
    overflow: visible;
  }

  .page-about .index-rail__link {
    white-space: normal;
    padding: .34rem 0;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .scope-item,
  .page-about .start-card,
  .page-about .index-rail__link,
  .page-about .crumbs__link {
    transition: none;
  }
}