.page-about{
  --about-gutter:clamp(20px,4vw,56px);
  --about-node-bg:rgba(23,39,92,.72);
  --about-node-bg-hover:rgba(23,39,92,.92);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero{
  position:relative;
  overflow:hidden;
  isolation:isolate;
  padding:128px 0 56px;
  background:linear-gradient(180deg,var(--ink-950) 0%,var(--ink-900) 100%);
  border-radius:0 0 var(--radius-lg) var(--radius-lg);
}

.page-about .about-hero__bg{
  position:absolute;
  inset:0;
  width:100%;
  height:100%;
  object-fit:cover;
  z-index:-2;
  opacity:.42;
  filter:saturate(.85) contrast(1.05);
}

.page-about .about-hero__veil{
  position:absolute;
  inset:0;
  z-index:-1;
  background-image:
    linear-gradient(rgba(169,183,208,.055) 1px,transparent 1px),
    linear-gradient(90deg,rgba(169,183,208,.055) 1px,transparent 1px),
    radial-gradient(90% 70% at 80% 8%,rgba(39,225,255,.20),transparent 62%),
    radial-gradient(70% 60% at 8% 96%,rgba(255,122,47,.14),transparent 60%),
    linear-gradient(180deg,rgba(7,13,36,.30) 0%,rgba(7,13,36,.86) 58%,var(--ink-950) 100%);
  background-size:72px 72px,72px 72px,auto,auto,auto;
}

.page-about .about-hero__inner{
  position:relative;
  display:grid;
  gap:22px;
  padding-inline:var(--about-gutter);
}

.page-about .about-hero__title{
  margin:0;
  font-size:clamp(32px,7.4vw,74px);
  line-height:1.06;
  letter-spacing:-.02em;
  font-weight:900;
  color:var(--paper);
}

.page-about .about-hero__lead{
  margin:0;
  max-width:46ch;
  font-size:clamp(15px,2.1vw,17.5px);
  line-height:1.8;
  color:var(--mist);
  border-left:2px solid var(--cyan);
  padding-left:16px;
}

.page-about .about-hero__stats{
  list-style:none;
  margin:8px 0 0;
  padding:0;
  display:grid;
  gap:14px;
}

.page-about .about-hero__stats li{
  display:flex;
  align-items:baseline;
  gap:10px;
  padding-top:12px;
  border-top:1px solid var(--line);
  font-size:13px;
  line-height:1.55;
  color:var(--mist);
}

.page-about .about-hero__stats b{
  font-family:var(--font-mono);
  font-size:22px;
  font-weight:600;
  letter-spacing:-.01em;
  color:var(--cyan);
  white-space:nowrap;
}

/* ---------- 主体两栏 ---------- */
.page-about .about-body{
  display:grid;
  gap:36px;
  padding-block:52px 72px;
}

.page-about .about-index{
  border-top:1px solid var(--line-strong);
  padding-top:14px;
}

.page-about .about-index__title{
  margin:0 0 10px;
  font-size:11.5px;
  letter-spacing:.22em;
  text-transform:uppercase;
  color:var(--cyan);
}

.page-about .about-index__list{
  list-style:none;
  margin:0;
  padding:0 0 6px;
  display:flex;
  gap:8px;
  overflow-x:auto;
  scrollbar-width:thin;
}

.page-about .about-index__list li{
  flex:0 0 auto;
}

.page-about .about-index__list a{
  display:flex;
  align-items:center;
  gap:8px;
  padding:8px 12px;
  border:1px solid var(--line);
  border-radius:var(--radius-pill);
  font-size:13px;
  color:var(--mist);
  text-decoration:none;
  white-space:nowrap;
  transition:color .22s,border-color .22s,background .22s;
}

.page-about .about-index__no{
  font-size:11px;
  color:var(--cyan);
  opacity:.85;
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible{
  color:var(--paper);
  border-color:var(--line-strong);
  background:rgba(39,225,255,.08);
}

/* ---------- 章节 ---------- */
.page-about .about-flow{
  display:grid;
  gap:52px;
  min-width:0;
}

.page-about .about-chapter{
  scroll-margin-top:96px;
}

.page-about .about-chapter .chapter-head{
  display:flex;
  align-items:baseline;
  gap:14px;
  padding-bottom:14px;
  margin-bottom:20px;
  border-bottom:1px solid var(--line);
}

.page-about .about-chapter .chapter-no{
  flex:0 0 auto;
  margin:0;
  font-family:var(--font-mono);
  font-size:clamp(30px,5.2vw,44px);
  line-height:1;
  color:transparent;
  -webkit-text-stroke:1px rgba(39,225,255,.55);
  letter-spacing:.02em;
}

.page-about .about-chapter__title{
  margin:0;
  font-size:clamp(20px,3.1vw,30px);
  line-height:1.28;
  font-weight:800;
  letter-spacing:-.01em;
  color:var(--paper);
}

.page-about .about-chapter > p{
  margin:0 0 14px;
  font-size:15.5px;
  line-height:1.85;
  color:var(--mist);
}

.page-about .about-chapter > p:last-of-type{
  margin-bottom:0;
}

.page-about .about-chapter strong{
  color:var(--orange);
  font-weight:600;
}

.page-about .about-link{
  color:var(--cyan);
  text-decoration:none;
  border-bottom:1px solid rgba(39,225,255,.4);
  padding-bottom:1px;
  transition:color .2s,border-color .2s;
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible{
  color:var(--paper);
  border-color:var(--paper);
}

/* ---------- 图片 ---------- */
.page-about .about-figure{
  margin:26px 0 0;
}

.page-about .about-figure img,
.page-about .about-dual__media img{
  display:block;
  width:100%;
  height:auto;
  border-radius:var(--radius-md);
  border:1px solid var(--line);
}

.page-about .about-figure figcaption,
.page-about .about-dual__media figcaption{
  margin-top:10px;
  font-size:12.5px;
  line-height:1.6;
  color:var(--mist);
  opacity:.85;
}

/* ---------- 双端对比 ---------- */
.page-about .about-dual{
  display:grid;
  gap:22px;
  margin-top:22px;
}

.page-about .about-dual__text p{
  margin:0 0 12px;
  font-size:15.5px;
  line-height:1.85;
  color:var(--mist);
}

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

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

/* ---------- 协作树 ---------- */
.page-about .about-tree{
  margin:24px 0 20px;
}

.page-about .about-tree__root{
  display:inline-block;
  margin:0;
  padding:9px 16px;
  border:1px solid var(--line-strong);
  border-radius:var(--radius-pill);
  background:var(--panel);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:var(--cyan);
}

.page-about .about-tree__branches{
  list-style:none;
  margin:0 0 0 18px;
  padding:18px 0 0 22px;
  border-left:1px solid var(--line-strong);
  display:grid;
  gap:14px;
}

.page-about .about-tree__branches > li{
  position:relative;
  min-width:0;
}

.page-about .about-tree__branches > li::before{
  content:"";
  position:absolute;
  left:-22px;
  top:22px;
  width:18px;
  height:1px;
  background:var(--line-strong);
}

.page-about .about-node{
  height:100%;
  padding:16px 16px 18px;
  border:1px solid var(--line);
  border-radius:var(--radius-md);
  background:var(--about-node-bg);
  box-shadow:var(--shadow);
  transition:border-color .25s ease,background .25s ease,transform .25s ease;
}

.page-about .about-node:hover,
.page-about .about-node:focus-visible,
.page-about .about-node:focus-within{
  border-color:var(--line-strong);
  background:var(--about-node-bg-hover);
  transform:translateY(-3px);
  outline:none;
}

.page-about .about-node__name{
  margin:0 0 8px;
  font-size:14.5px;
  font-weight:700;
  letter-spacing:.04em;
  color:var(--cyan);
}

.page-about .about-node__duty{
  margin:0;
  font-size:14px;
  line-height:1.75;
  color:var(--mist);
}

/* ---------- 版本条带 ---------- */
.page-about .about-rail{
  margin-top:18px;
}

.page-about .about-rail .rail-tools{
  display:flex;
  gap:8px;
  justify-content:flex-end;
  margin-bottom:10px;
}

.page-about .about-rail .rail-btn{
  width:34px;
  height:34px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border:1px solid var(--line);
  border-radius:var(--radius-pill);
  background:rgba(23,39,92,.6);
  color:var(--mist);
  font-size:17px;
  line-height:1;
  cursor:pointer;
  transition:color .2s,border-color .2s,background .2s;
}

.page-about .about-rail .rail-btn:hover,
.page-about .about-rail .rail-btn:focus-visible{
  color:var(--ink-950);
  background:var(--cyan);
  border-color:var(--cyan);
}

.page-about .about-rail .rail__track{
  display:flex;
  gap:14px;
  overflow-x:auto;
  padding-bottom:10px;
  scroll-snap-type:x proximity;
  scrollbar-width:thin;
}

.page-about .about-ver{
  flex:0 0 78%;
  min-width:230px;
  scroll-snap-align:start;
  padding:18px;
  border:1px solid var(--line);
  border-top:2px solid var(--orange);
  border-radius:var(--radius-md);
  background:var(--panel);
}

.page-about .about-ver__tag{
  margin:0 0 8px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.14em;
  color:var(--amber);
}

.page-about .about-ver__title{
  margin:0 0 8px;
  font-size:16px;
  line-height:1.4;
  font-weight:700;
  color:var(--paper);
}

.page-about .about-ver__text{
  margin:0;
  font-size:13.5px;
  line-height:1.75;
  color:var(--mist);
}

/* ---------- 场景清单 ---------- */
.page-about .about-scenes{
  list-style:none;
  margin:22px 0 18px;
  padding:0;
  display:grid;
  gap:14px;
}

.page-about .about-scenes li{
  padding:16px 16px 18px;
  border:1px solid var(--line);
  border-left:2px solid var(--cyan);
  border-radius:0 var(--radius-md) var(--radius-md) 0;
  background:rgba(14,24,56,.55);
}

.page-about .about-scenes__title{
  margin:0 0 7px;
  font-size:15px;
  font-weight:700;
  letter-spacing:.03em;
  color:var(--paper);
}

.page-about .about-scenes li p{
  margin:0;
  font-size:14px;
  line-height:1.75;
  color:var(--mist);
}

/* ---------- 结尾引导 ---------- */
.page-about .about-cta{
  padding:26px 22px 28px;
  border:1px solid var(--line-strong);
  border-radius:var(--radius-lg);
  background:
    radial-gradient(120% 140% at 100% 0%,rgba(255,122,47,.16),transparent 58%),
    radial-gradient(90% 120% at 0% 100%,rgba(39,225,255,.14),transparent 60%),
    rgba(14,24,56,.85);
}

.page-about .about-cta__title{
  margin:10px 0 12px;
  font-size:clamp(20px,3vw,27px);
  line-height:1.35;
  font-weight:800;
  color:var(--paper);
}

.page-about .about-cta__text{
  margin:0 0 20px;
  font-size:14.5px;
  line-height:1.85;
  color:var(--mist);
}

.page-about .about-cta__actions{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
}

/* ---------- 平板与桌面 ---------- */
@media (min-width:720px){
  .page-about .about-hero{
    padding:150px 0 68px;
  }

  .page-about .about-hero__stats{
    grid-template-columns:repeat(3,minmax(0,1fr));
    gap:20px;
    margin-top:14px;
  }

  .page-about .about-hero__stats li{
    flex-direction:column;
    gap:6px;
  }

  .page-about .about-tree__branches{
    grid-template-columns:repeat(3,minmax(0,1fr));
    gap:16px;
    margin:0;
    padding:24px 0 0;
    border-left:0;
    position:relative;
  }

  .page-about .about-tree__branches::before{
    content:"";
    position:absolute;
    top:0;
    left:0;
    right:0;
    height:1px;
    background:linear-gradient(90deg,var(--line-strong),rgba(39,225,255,.06));
  }

  .page-about .about-tree__branches > li::before{
    left:50%;
    top:-24px;
    width:1px;
    height:24px;
  }

  .page-about .about-ver{
    flex:0 0 42%;
  }

  .page-about .about-scenes{
    grid-template-columns:repeat(2,minmax(0,1fr));
    gap:16px;
  }

  .page-about .about-cta{
    padding:34px 32px 36px;
  }
}

@media (min-width:980px){
  .page-about .about-body{
    grid-template-columns:206px minmax(0,1fr);
    gap:60px;
    padding-block:84px 104px;
  }

  .page-about .about-index{
    position:sticky;
    top:104px;
    align-self:start;
    padding-top:18px;
  }

  .page-about .about-index__list{
    flex-direction:column;
    gap:2px;
    overflow:visible;
    padding:0;
  }

  .page-about .about-index__list a{
    padding:9px 0 9px 12px;
    border:0;
    border-left:1px solid var(--line);
    border-radius:0;
    white-space:normal;
    line-height:1.45;
  }

  .page-about .about-index__list a:hover,
  .page-about .about-index__list a:focus-visible{
    border-left-color:var(--cyan);
    background:linear-gradient(90deg,rgba(39,225,255,.10),transparent 85%);
  }

  .page-about .about-flow{
    gap:64px;
  }

  .page-about .about-dual{
    grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr);
    gap:28px;
    align-items:start;
    margin-top:26px;
  }

  .page-about .about-figure{
    margin-top:30px;
  }

  .page-about .about-ver{
    flex:0 0 30%;
  }

  .page-about .about-cta__text{
    max-width:62ch;
  }
}

@media (prefers-reduced-motion:reduce){
  .page-about .about-node,
  .page-about .about-index__list a,
  .page-about .about-rail .rail-btn{
    transition:none;
  }

  .page-about .about-node:hover,
  .page-about .about-node:focus-visible,
  .page-about .about-node:focus-within{
    transform:none;
  }

  .page-about .about-rail .rail__track{
    scroll-behavior:auto;
  }
}