.page-about{
  --ab-rail:64px;
  --ab-shift:clamp(0px,5vw,84px);
  --ab-gap:clamp(22px,3.4vw,52px);
}

/* ---------- 封面 ---------- */
.page-about .about-cover{
  position:relative;
  overflow:hidden;
  padding:clamp(24px,4vw,52px) 0 clamp(36px,5.4vw,84px);
  border-bottom:1px solid var(--line);
  background:
    radial-gradient(120% 92% at 90% 0%, rgba(53,230,210,.11), transparent 58%),
    radial-gradient(88% 72% at 2% 104%, rgba(255,90,60,.09), transparent 60%);
}

.page-about .about-cover::before{
  content:"";
  position:absolute;
  inset:0;
  background-image:
    linear-gradient(90deg, var(--line-soft) 1px, transparent 1px),
    linear-gradient(180deg, var(--line-soft) 1px, transparent 1px);
  background-size:96px 96px;
  opacity:.5;
  pointer-events:none;
}

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

.page-about .breadcrumb{
  font-family:var(--font-mono);
  font-size:13px;
  letter-spacing:.02em;
  color:var(--c-graphite);
  margin-bottom:clamp(20px,3.2vw,38px);
}

.page-about .breadcrumb a{
  color:var(--c-graphite);
  text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color .2s var(--ease), border-color .2s var(--ease);
}

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

.page-about .breadcrumb__sep{
  margin:0 .5em;
  color:var(--c-blueprint);
}

.page-about .about-cover__grid{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:clamp(26px,4vw,56px);
  align-items:end;
}

.page-about .eyebrow{
  font-family:var(--font-mono);
  font-size:13px;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--c-cyan);
  margin:0 0 clamp(14px,2vw,24px);
}

.page-about .about-cover h1{
  margin:0 0 clamp(18px,2.4vw,28px);
  max-width:17em;
  font-family:var(--font-display);
  font-size:clamp(32px,5.2vw,66px);
  font-weight:900;
  line-height:1.08;
  letter-spacing:-.02em;
  color:var(--c-ice);
}

.page-about .about-cover .lead{
  margin:0;
  max-width:36em;
  font-size:clamp(16px,1.35vw,18px);
  line-height:1.78;
  color:var(--c-graphite);
}

.page-about .about-cover__stats{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:1px;
  background:var(--line-soft);
  border:1px solid var(--line-soft);
}

.page-about .about-cover__stat{
  background:var(--c-panel-2);
  padding:16px 16px 18px;
  display:grid;
  gap:6px;
  align-content:start;
}

.page-about .about-cover__v{
  font-size:clamp(24px,2.8vw,34px);
  font-weight:700;
  line-height:1;
  letter-spacing:-.03em;
  font-variant-numeric:tabular-nums;
  color:var(--c-cyan);
}

.page-about .about-cover__k{
  font-size:13px;
  line-height:1.55;
  color:var(--c-graphite);
}

/* ---------- 长卷骨架 ---------- */
.page-about .about-shell{
  display:grid;
  grid-template-columns:minmax(0,1fr);
}

.page-about .about-rail{
  display:none;
}

.page-about .about-body{
  min-width:0;
  padding-bottom:clamp(56px,7vw,120px);
}

.page-about .about-chapter{
  padding:clamp(44px,6vw,94px) 0;
  border-top:1px solid var(--line-soft);
  scroll-margin-top:110px;
}

.page-about .about-chapter:first-child{
  border-top:0;
}

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

/* ---------- 章节标题 ---------- */
.page-about .sec-head{
  display:grid;
  grid-template-columns:auto minmax(0,1fr);
  gap:4px 18px;
  align-items:baseline;
  margin:0 0 clamp(24px,3.2vw,44px);
}

.page-about .sec-head__num{
  grid-row:1 / span 2;
  font-family:var(--font-mono);
  font-size:clamp(40px,6.4vw,78px);
  font-weight:700;
  line-height:.86;
  letter-spacing:-.05em;
  font-variant-numeric:tabular-nums;
  color:var(--c-cyan);
}

.page-about .sec-head__title{
  margin:0;
  font-family:var(--font-display);
  font-size:clamp(21px,2.6vw,33px);
  font-weight:800;
  line-height:1.22;
  letter-spacing:-.01em;
  color:var(--c-ice);
}

.page-about .sec-head__note{
  margin:0;
  font-family:var(--font-mono);
  font-size:13px;
  letter-spacing:.06em;
  color:var(--c-graphite);
}

/* ---------- 正文 ---------- */
.page-about .about-text p{
  margin:0 0 1.1em;
  max-width:34em;
  font-size:17px;
  line-height:1.78;
  color:var(--c-ice);
}

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

.page-about .about-text--after{
  margin-top:clamp(22px,3vw,38px);
}

.page-about .ab-key{
  font-family:var(--font-mono);
  font-variant-numeric:tabular-nums;
  font-weight:700;
  color:var(--c-cyan);
}

/* ---------- 图片 ---------- */
.page-about .about-figure{
  margin:clamp(24px,3.4vw,48px) 0 0;
}

.page-about .about-figure img{
  display:block;
  width:100%;
  max-width:100%;
  height:auto;
  aspect-ratio:16 / 9;
  object-fit:cover;
  border:1px solid var(--line);
  background:var(--c-panel-2);
}

.page-about .about-figure .media__cap{
  display:block;
  margin-top:12px;
  font-family:var(--font-mono);
  font-size:13px;
  line-height:1.6;
  color:var(--c-graphite);
}

/* ---------- 版本标签页 ---------- */
.page-about .ab-versions{
  margin-top:clamp(22px,3vw,36px);
}

.page-about .ab-versions .tabs__list{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:1px;
  background:var(--line-soft);
  border:1px solid var(--line-soft);
}

.page-about .ab-ver{
  display:grid;
  gap:8px;
  align-content:start;
  min-height:96px;
  padding:16px 16px 18px;
  border:0;
  background:var(--c-panel-2);
  color:var(--c-graphite);
  font:inherit;
  text-align:left;
  cursor:pointer;
  transition:background .22s var(--ease), color .22s var(--ease);
}

.page-about .ab-ver:hover{
  background:var(--c-panel);
  color:var(--c-ice);
}

.page-about .ab-ver[aria-selected="true"]{
  background:var(--c-panel);
  color:var(--c-ice);
  box-shadow:inset 0 3px 0 var(--c-cyan);
}

.page-about .ab-ver__no{
  font-family:var(--font-mono);
  font-size:20px;
  font-weight:700;
  letter-spacing:-.01em;
  line-height:1;
}

.page-about .ab-ver[aria-selected="true"] .ab-ver__no{
  color:var(--c-cyan);
}

.page-about .ab-ver__yr{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.08em;
  color:var(--c-graphite);
}

.page-about .ab-ver__name{
  font-size:14px;
  font-weight:600;
  line-height:1.4;
}

.page-about .ab-ver__bar{
  display:block;
  height:3px;
  background:rgba(46,111,183,.3);
  overflow:hidden;
}

.page-about .ab-ver__bar i{
  display:block;
  height:100%;
  background:var(--c-cyan);
  opacity:.5;
  transition:opacity .22s var(--ease);
}

.page-about .ab-ver[aria-selected="true"] .ab-ver__bar i{
  opacity:1;
}

.page-about .ab-ver--1 .ab-ver__bar i{ width:25%; }
.page-about .ab-ver--2 .ab-ver__bar i{ width:50%; }
.page-about .ab-ver--3 .ab-ver__bar i{ width:75%; }
.page-about .ab-ver--4 .ab-ver__bar i{ width:100%; }

.page-about .ab-versions .tabs__panel{
  padding:clamp(20px,3vw,36px);
  border:1px solid var(--line-soft);
  border-top:0;
  background:var(--c-panel-2);
}

.page-about .ab-versions .tabs__panel[hidden]{
  display:none;
}

.page-about .ab-panel__kicker{
  margin:0 0 10px;
  font-family:var(--font-mono);
  font-size:13px;
  letter-spacing:.12em;
  color:var(--c-signal);
}

.page-about .ab-panel__title{
  margin:0 0 12px;
  font-family:var(--font-display);
  font-size:clamp(19px,2.1vw,24px);
  font-weight:800;
  line-height:1.35;
  color:var(--c-ice);
}

.page-about .ab-panel__text{
  margin:0;
  max-width:34em;
  font-size:16px;
  line-height:1.78;
  color:var(--c-graphite);
}

/* ---------- 编审流程 ---------- */
.page-about .about-split{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:clamp(26px,3.4vw,48px);
}

.page-about .ab-steps{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  gap:1px;
  background:var(--line-soft);
  border:1px solid var(--line-soft);
}

.page-about .ab-steps__item{
  display:grid;
  grid-template-columns:auto minmax(0,1fr);
  gap:6px 16px;
  align-items:baseline;
  padding:clamp(18px,2.4vw,28px);
  background:var(--c-panel-2);
}

.page-about .ab-steps__no{
  grid-row:1 / span 2;
  font-family:var(--font-mono);
  font-size:22px;
  font-weight:700;
  line-height:1;
  color:var(--c-cyan);
}

.page-about .ab-steps__title{
  margin:0;
  font-size:17px;
  font-weight:700;
  color:var(--c-ice);
}

.page-about .ab-steps__item p{
  margin:0;
  font-size:15px;
  line-height:1.75;
  color:var(--c-graphite);
}

.page-about .about-split__media{
  margin-top:0;
}

.page-about .about-split__media img{
  aspect-ratio:3 / 2;
}

/* ---------- 团队 ---------- */
.page-about .ab-team{
  list-style:none;
  margin:clamp(24px,3.4vw,42px) 0 0;
  padding:0;
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:1px;
  background:var(--line-soft);
  border:1px solid var(--line-soft);
}

.page-about .ab-team__item{
  display:grid;
  gap:10px;
  align-content:start;
  padding:clamp(20px,2.8vw,32px);
  background:var(--c-panel-2);
  transition:background .22s var(--ease);
}

.page-about .ab-team__item:hover{
  background:var(--c-panel);
}

.page-about .ab-team__num{
  font-family:var(--font-mono);
  font-size:clamp(42px,5vw,62px);
  font-weight:700;
  line-height:1;
  letter-spacing:-.04em;
  font-variant-numeric:tabular-nums;
  color:var(--c-ice);
}

.page-about .ab-team__num small{
  font-size:.3em;
  margin-left:.5em;
  vertical-align:super;
  letter-spacing:0;
  color:var(--c-cyan);
}

.page-about .ab-team__role{
  font-size:16px;
  font-weight:700;
  color:var(--c-cyan);
}

.page-about .ab-team__desc{
  margin:0;
  font-size:15px;
  line-height:1.72;
  color:var(--c-graphite);
}

@media (hover:hover) and (min-width:700px){
  .page-about .ab-team__item:hover{
    box-shadow:inset 0 0 0 1px var(--line);
  }
  .page-about .ab-team__desc{
    max-height:0;
    opacity:0;
    overflow:hidden;
    transition:max-height .34s var(--ease), opacity .26s var(--ease);
  }
  .page-about .ab-team__item:hover .ab-team__desc,
  .page-about .ab-team__item:focus-within .ab-team__desc{
    max-height:22em;
    opacity:1;
  }
}

/* ---------- 索引维度 ---------- */
.page-about .ab-dims{
  list-style:none;
  margin:clamp(24px,3.4vw,42px) 0 0;
  padding:0;
  border-top:1px solid var(--line-soft);
}

.page-about .ab-dims__item{
  display:grid;
  grid-template-columns:52px minmax(0,1fr);
  gap:4px 16px;
  align-items:baseline;
  padding:clamp(14px,1.9vw,20px) 0;
  border-bottom:1px solid var(--line-soft);
}

.page-about .ab-dims__no{
  grid-row:1 / span 2;
  font-family:var(--font-mono);
  font-size:14px;
  font-weight:700;
  letter-spacing:.08em;
  color:var(--c-cyan);
}

.page-about .ab-dims__title{
  margin:0;
  font-size:17px;
  font-weight:700;
  color:var(--c-ice);
}

.page-about .ab-dims__text{
  margin:0;
  max-width:42em;
  font-size:15px;
  line-height:1.75;
  color:var(--c-graphite);
}

/* ---------- 协作 ---------- */
.page-about .ab-collab{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:clamp(26px,3.4vw,48px);
}

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

.page-about .ab-collab__row{
  display:grid;
  grid-template-columns:auto minmax(0,1fr);
  gap:4px 16px;
  align-items:baseline;
  padding:clamp(16px,2.2vw,24px) 0;
  border-bottom:1px solid var(--line-soft);
}

.page-about .ab-collab__v{
  font-family:var(--font-mono);
  font-size:clamp(28px,3.4vw,40px);
  font-weight:700;
  line-height:1;
  letter-spacing:-.04em;
  font-variant-numeric:tabular-nums;
  color:var(--c-signal);
}

.page-about .ab-collab__k{
  font-size:16px;
  font-weight:700;
  color:var(--c-ice);
}

.page-about .ab-collab__d{
  grid-column:2;
  font-size:14px;
  line-height:1.7;
  color:var(--c-graphite);
}

/* ---------- 资质 ---------- */
.page-about .about-figure--wide{
  margin-top:0;
}

.page-about .ab-creds{
  list-style:none;
  margin:clamp(24px,3.2vw,40px) 0 0;
  padding:0;
  border-top:1px solid var(--line-soft);
}

.page-about .ab-creds__item{
  display:grid;
  grid-template-columns:auto minmax(0,1fr);
  gap:4px 18px;
  align-items:start;
  padding:clamp(18px,2.4vw,26px) 0;
  border-bottom:1px solid var(--line-soft);
}

.page-about .ab-creds__no{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  width:30px;
  height:30px;
  font-family:var(--font-mono);
  font-size:13px;
  font-weight:700;
  color:var(--c-deep);
  background:var(--c-cyan);
}

.page-about .ab-creds__title{
  margin:0 0 6px;
  font-size:17px;
  font-weight:700;
  line-height:1.4;
  color:var(--c-ice);
}

.page-about .ab-creds__item p{
  margin:0;
  max-width:40em;
  font-size:15px;
  line-height:1.75;
  color:var(--c-graphite);
}

/* ---------- CTA ---------- */
.page-about .ab-cta{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:clamp(16px,2.2vw,24px);
}

.page-about .ab-cta__card{
  display:grid;
  gap:10px;
  align-content:start;
  padding:clamp(22px,3vw,36px);
  border:1px solid var(--line);
  background:var(--c-panel-2);
  color:inherit;
  text-decoration:none;
  transition:background .24s var(--ease), border-color .24s var(--ease), transform .24s var(--ease);
}

.page-about .ab-cta__card:hover,
.page-about .ab-cta__card:focus-visible{
  background:var(--c-panel);
  border-color:var(--line-strong);
  transform:translateY(-2px);
}

.page-about .ab-cta__card--signal{
  border-color:rgba(255,90,60,.42);
}

.page-about .ab-cta__card--signal:hover,
.page-about .ab-cta__card--signal:focus-visible{
  border-color:var(--c-signal);
}

.page-about .ab-cta__k{
  font-family:var(--font-mono);
  font-size:13px;
  letter-spacing:.1em;
  color:var(--c-graphite);
}

.page-about .ab-cta__title{
  margin:0;
  font-family:var(--font-display);
  font-size:clamp(19px,2.2vw,25px);
  font-weight:800;
  line-height:1.32;
  color:var(--c-ice);
}

.page-about .ab-cta__text{
  margin:0;
  max-width:32em;
  font-size:15px;
  line-height:1.75;
  color:var(--c-graphite);
}

.page-about .ab-cta__go{
  margin-top:6px;
  font-family:var(--font-mono);
  font-size:14px;
  font-weight:700;
  color:var(--c-cyan);
}

.page-about .ab-cta__card--signal .ab-cta__go{
  color:var(--c-signal);
}

.page-about .ab-more{
  margin:clamp(22px,3vw,36px) 0 0;
  font-size:15px;
  line-height:1.75;
  color:var(--c-graphite);
}

.page-about .ab-more a{
  color:var(--c-cyan);
  text-decoration:none;
  border-bottom:1px solid var(--line-strong);
}

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

/* ---------- 轨道（桌面端） ---------- */
@media (min-width:1080px){
  .page-about .about-shell{
    grid-template-columns:var(--ab-rail) minmax(0,1fr);
    column-gap:clamp(28px,4vw,64px);
  }

  .page-about .about-rail{
    display:block;
    position:sticky;
    top:104px;
    align-self:start;
    margin-top:clamp(44px,6vw,94px);
  }

  .page-about .about-rail__list{
    position:relative;
    list-style:none;
    margin:0;
    padding:0;
    display:grid;
    gap:4px;
  }

  .page-about .about-rail__list::before{
    content:"";
    position:absolute;
    left:9px;
    top:8px;
    bottom:8px;
    width:1px;
    background:linear-gradient(180deg, var(--c-blueprint), rgba(46,111,183,0));
  }

  .page-about .about-rail__link{
    position:relative;
    display:flex;
    align-items:center;
    gap:8px;
    min-height:32px;
    padding:4px 4px 4px 0;
    font-family:var(--font-mono);
    font-size:13px;
    font-variant-numeric:tabular-nums;
    text-decoration:none;
    color:var(--c-graphite);
    transition:color .2s var(--ease);
  }

  .page-about .about-rail__dot{
    flex:none;
    width:7px;
    height:7px;
    margin-left:6px;
    border:1px solid var(--line-strong);
    background:var(--c-deep);
    transition:background .2s var(--ease), box-shadow .2s var(--ease);
  }

  .page-about .about-rail__link:hover,
  .page-about .about-rail__link:focus-visible{
    color:var(--c-cyan);
    outline:none;
  }

  .page-about .about-rail__link:hover .about-rail__dot,
  .page-about .about-rail__link:focus-visible .about-rail__dot{
    background:var(--c-cyan);
    box-shadow:0 0 0 4px rgba(53,230,210,.16);
  }

  .page-about .about-rail__label{
    position:absolute;
    left:calc(100% + 10px);
    top:50%;
    transform:translateY(-50%);
    padding:4px 9px;
    white-space:nowrap;
    font-family:var(--font-body);
    font-size:12px;
    color:var(--c-ice);
    background:var(--c-panel);
    border:1px solid var(--line);
    opacity:0;
    pointer-events:none;
    transition:opacity .18s var(--ease);
  }

  .page-about .about-rail__link:hover .about-rail__label,
  .page-about .about-rail__link:focus-visible .about-rail__label{
    opacity:1;
  }

  /* 章节错位 */
  .page-about .about-chapter--offset .about-chapter__body{
    padding-left:var(--ab-shift);
  }

  .page-about .about-cover__grid{
    grid-template-columns:minmax(0,1.6fr) minmax(240px,1fr);
  }
}

@media (min-width:760px){
  .page-about .about-cover__stats{
    grid-template-columns:repeat(2,minmax(0,1fr));
  }

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

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

  .page-about .ab-dims__item{
    grid-template-columns:52px 120px minmax(0,1fr);
  }

  .page-about .ab-dims__no{
    grid-row:1;
  }

  .page-about .ab-collab{
    grid-template-columns:minmax(0,1.15fr) minmax(0,1fr);
    align-items:start;
  }

  .page-about .about-split{
    grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr);
    align-items:start;
  }

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

@media (max-width:480px){
  .page-about .sec-head{
    grid-template-columns:minmax(0,1fr);
    gap:8px;
  }

  .page-about .sec-head__num{
    grid-row:auto;
    font-size:34px;
  }

  .page-about .ab-steps__item,
  .page-about .ab-dims__item,
  .page-about .ab-creds__item{
    grid-template-columns:minmax(0,1fr);
  }

  .page-about .ab-steps__no,
  .page-about .ab-dims__no{
    grid-row:auto;
  }

  .page-about .ab-collab__d{
    grid-column:1;
  }
}

@media (prefers-reduced-motion: reduce){
  .page-about .ab-cta__card,
  .page-about .ab-team__item,
  .page-about .ab-ver,
  .page-about .about-rail__dot{
    transition:none;
  }

  .page-about .ab-cta__card:hover,
  .page-about .ab-cta__card:focus-visible{
    transform:none;
  }
}
</main>