.page-about{
  --about-rail:140px;
  background:var(--ky-ink-900);
  color:var(--ky-text);
  font-family:var(--ky-font-body);
  padding:0 0 clamp(56px,9vw,96px);
}

.page-about .ky-container{
  position:relative;
}

.page-about .ky-breadcrumb{
  margin:clamp(20px,4vw,34px) 0 clamp(16px,3vw,24px);
}

/* ---------- 首屏声明 ---------- */
.page-about .about-hero{
  position:relative;
  display:grid;
  gap:16px;
  padding:clamp(20px,3.5vw,34px) 0 clamp(24px,4vw,38px);
  border-bottom:1px solid var(--ky-line);
}

.page-about .about-hero::after{
  content:"";
  position:absolute;
  top:0;
  right:0;
  width:clamp(90px,24vw,240px);
  height:5px;
  background:linear-gradient(90deg,var(--ky-cyan),var(--ky-orange));
}

.page-about .about-hero__title{
  margin:0;
  font-family:var(--ky-font-display);
  font-weight:800;
  font-size:clamp(32px,7.2vw,66px);
  line-height:1.06;
  letter-spacing:-.005em;
  color:var(--ky-text);
  max-width:15em;
}

.page-about .about-hero__lead{
  margin:0;
  max-width:64ch;
  font-size:clamp(15px,1.6vw,17px);
  line-height:1.85;
  color:var(--ky-text-2);
}

.page-about .about-stats{
  list-style:none;
  margin:6px 0 0;
  padding:0;
  display:grid;
  grid-template-columns:1fr;
  gap:1px;
  background:var(--ky-line);
  border:1px solid var(--ky-line);
}

.page-about .about-stats__item{
  background:var(--ky-ink-900);
  padding:16px 18px;
  display:flex;
  flex-direction:column;
  gap:6px;
}

.page-about .about-stats__value{
  font-family:var(--ky-font-mono);
  font-size:clamp(21px,3.6vw,27px);
  font-weight:700;
  line-height:1;
  color:var(--ky-cyan);
}

.page-about .about-stats__label{
  font-size:13px;
  line-height:1.6;
  color:var(--ky-text-2);
}

/* ---------- 纵向叙事轨道 ---------- */
.page-about .about-flow{
  position:relative;
  margin-top:clamp(32px,5vw,56px);
}

.page-about .about-flow::before{
  content:"";
  position:absolute;
  left:5px;
  top:12px;
  bottom:12px;
  width:1px;
  background:linear-gradient(180deg,transparent,var(--ky-line) 5%,var(--ky-line) 95%,transparent);
}

.page-about .about-chapter{
  position:relative;
  display:grid;
  grid-template-columns:1fr;
  gap:14px;
  padding:0 0 clamp(34px,5.5vw,48px);
}

.page-about .about-chapter:last-child{
  padding-bottom:0;
}

.page-about .about-chapter__rail{
  position:relative;
  display:flex;
  align-items:baseline;
  gap:10px;
  padding-left:28px;
  font-family:var(--ky-font-mono);
  font-size:12.5px;
  letter-spacing:.14em;
  color:var(--ky-text-2);
}

.page-about .about-chapter__dot{
  position:absolute;
  left:0;
  top:3px;
  width:10px;
  height:10px;
  box-sizing:border-box;
  border:1px solid var(--ky-cyan);
  background:var(--ky-ink-900);
  box-shadow:0 0 0 5px var(--ky-ink-900);
  transform:rotate(45deg);
  transition:background .25s var(--ky-ease),border-color .25s var(--ky-ease);
}

.page-about .about-chapter:target .about-chapter__dot{
  background:var(--ky-cyan);
}

.page-about .about-chapter__idx{
  color:var(--ky-cyan);
  font-weight:700;
}

.page-about .about-chapter__label{
  color:var(--ky-text-2);
}

.page-about .about-chapter__body{
  display:grid;
  gap:16px;
  align-content:start;
}

.page-about .about-chapter__title{
  margin:0;
  font-family:var(--ky-font-display);
  font-weight:800;
  font-size:clamp(23px,3.6vw,36px);
  line-height:1.16;
  color:var(--ky-text);
}

.page-about .about-chapter__body > p{
  margin:0;
  max-width:66ch;
  font-size:15.5px;
  line-height:1.85;
  color:var(--ky-text-2);
}

/* ---------- 摘要块 ---------- */
.page-about .about-note{
  position:relative;
  padding:16px 20px 16px 22px;
  background:var(--ky-ink-700);
  box-shadow:inset 2px 0 0 var(--ky-cyan);
  clip-path:polygon(0 0,100% 0,100% calc(100% - 14px),calc(100% - 14px) 100%,0 100%);
  max-width:70ch;
}

.page-about .about-note--amber{
  box-shadow:inset 2px 0 0 var(--ky-orange);
}

.page-about .about-note__k{
  display:block;
  margin-bottom:8px;
  font-family:var(--ky-font-mono);
  font-size:12px;
  letter-spacing:.14em;
  color:var(--ky-cyan);
}

.page-about .about-note--amber .about-note__k{
  color:var(--ky-orange);
}

.page-about .about-note p{
  margin:0;
  font-size:14.5px;
  line-height:1.78;
  color:var(--ky-text);
}

/* ---------- 术语折叠 ---------- */
.page-about .about-term{
  max-width:70ch;
  border:1px solid var(--ky-line);
  background:var(--ky-ink-800);
}

.page-about .about-term summary{
  display:flex;
  align-items:center;
  gap:12px;
  padding:13px 18px;
  cursor:pointer;
  list-style:none;
  font-family:var(--ky-font-mono);
  font-size:13px;
  letter-spacing:.03em;
  color:var(--ky-cyan);
}

.page-about .about-term summary::-webkit-details-marker{
  display:none;
}

.page-about .about-term summary::before{
  content:"";
  flex:0 0 auto;
  width:7px;
  height:7px;
  border-right:1.5px solid var(--ky-cyan);
  border-bottom:1.5px solid var(--ky-cyan);
  transform:rotate(-45deg);
  transition:transform .22s var(--ky-ease);
}

.page-about .about-term[open] summary::before{
  transform:rotate(45deg);
}

.page-about .about-term summary:focus-visible{
  outline:2px solid var(--ky-cyan);
  outline-offset:-2px;
}

.page-about .about-term__body{
  margin:0;
  padding:0 18px 18px;
  font-size:14.5px;
  line-height:1.8;
  color:var(--ky-text-2);
}

/* ---------- 图组 ---------- */
.page-about .about-figure{
  position:relative;
  margin:0;
  border:1px solid var(--ky-line);
  background:var(--ky-ink-800);
  overflow:hidden;
}

.page-about .about-figure::before{
  content:"";
  position:absolute;
  top:0;
  left:0;
  width:46px;
  height:46px;
  background:var(--ky-cyan);
  clip-path:polygon(0 0,100% 0,0 100%);
  opacity:.85;
  pointer-events:none;
}

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

.page-about .about-figure figcaption{
  padding:11px 16px;
  border-top:1px solid var(--ky-line);
  font-family:var(--ky-font-mono);
  font-size:12.5px;
  line-height:1.6;
  letter-spacing:.02em;
  color:var(--ky-text-2);
}

/* ---------- 要点列表 ---------- */
.page-about .about-check{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  gap:12px;
  max-width:66ch;
}

.page-about .about-check__item{
  position:relative;
  padding-left:26px;
  font-size:15px;
  line-height:1.78;
  color:var(--ky-text);
}

.page-about .about-check__item::before{
  content:"";
  position:absolute;
  left:0;
  top:.6em;
  width:8px;
  height:8px;
  background:var(--ky-cyan);
  transform:rotate(45deg);
}

/* ---------- 覆盖数据 ---------- */
.page-about .about-metrics{
  list-style:none;
  margin:6px 0 0;
  padding:0;
  display:grid;
  grid-template-columns:1fr;
  gap:1px;
  background:var(--ky-line);
  border:1px solid var(--ky-line);
}

.page-about .about-metrics__item{
  background:var(--ky-ink-900);
  padding:18px 18px 20px;
  display:grid;
  gap:6px;
  align-content:start;
}

.page-about .about-metrics__value{
  font-family:var(--ky-font-mono);
  font-size:clamp(26px,4.8vw,36px);
  font-weight:700;
  line-height:1;
  color:var(--ky-cyan);
}

.page-about .about-metrics__label{
  font-size:13px;
  color:var(--ky-text-2);
}

.page-about .about-metrics__desc{
  margin:4px 0 0;
  font-size:13.5px;
  line-height:1.72;
  color:var(--ky-text-2);
}

/* ---------- 行动面板 ---------- */
.page-about .about-next{
  margin-top:clamp(46px,7vw,84px);
  padding-top:clamp(26px,4vw,40px);
  border-top:1px solid var(--ky-line);
}

.page-about .about-next__head{
  display:grid;
  gap:10px;
  max-width:62ch;
}

.page-about .about-next__title{
  margin:0;
  font-family:var(--ky-font-display);
  font-weight:800;
  font-size:clamp(24px,3.6vw,38px);
  line-height:1.14;
  color:var(--ky-text);
}

.page-about .about-next__desc{
  margin:0;
  font-size:15px;
  line-height:1.78;
  color:var(--ky-text-2);
}

.page-about .about-next__grid{
  list-style:none;
  margin:24px 0 0;
  padding:0;
  display:grid;
  grid-template-columns:1fr;
  gap:1px;
  background:var(--ky-line);
  border:1px solid var(--ky-line);
}

.page-about .about-next__item{
  background:var(--ky-ink-900);
}

.page-about .about-next__link{
  position:relative;
  display:grid;
  gap:8px;
  height:100%;
  padding:20px 20px 22px;
  text-decoration:none;
  color:var(--ky-text);
  transition:background .25s var(--ky-ease);
}

.page-about .about-next__link::after{
  content:"";
  position:absolute;
  top:0;
  bottom:0;
  left:0;
  width:2px;
  background:var(--ky-cyan);
  transform:scaleY(0);
  transform-origin:top;
  transition:transform .28s var(--ky-ease);
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible{
  background:var(--ky-ink-700);
}

.page-about .about-next__link:hover::after,
.page-about .about-next__link:focus-visible::after{
  transform:scaleY(1);
}

.page-about .about-next__link:focus-visible{
  outline:2px solid var(--ky-cyan);
  outline-offset:-2px;
}

.page-about .about-next__k{
  font-family:var(--ky-font-display);
  font-size:20px;
  font-weight:700;
  letter-spacing:.02em;
  color:var(--ky-text);
}

.page-about .about-next__v{
  font-size:14.5px;
  line-height:1.75;
  color:var(--ky-text-2);
}

/* ---------- 断点 ---------- */
@media (min-width:560px){
  .page-about .about-stats{
    grid-template-columns:repeat(3,minmax(0,1fr));
  }
}

@media (min-width:700px){
  .page-about .about-metrics{
    grid-template-columns:repeat(3,minmax(0,1fr));
  }
  .page-about .about-next__grid{
    grid-template-columns:repeat(2,minmax(0,1fr));
  }
}

@media (min-width:900px){
  .page-about .about-chapter{
    grid-template-columns:var(--about-rail) minmax(0,1fr);
    gap:clamp(24px,4vw,52px);
    padding-bottom:clamp(46px,6vw,74px);
  }

  .page-about .about-chapter__rail{
    flex-direction:column;
    align-items:flex-start;
    gap:8px;
    position:sticky;
    top:96px;
    align-self:start;
  }

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

@media (prefers-reduced-motion:reduce){
  .page-about .about-chapter__dot,
  .page-about .about-term summary::before,
  .page-about .about-next__link,
  .page-about .about-next__link::after{
    transition-duration:.001ms;
  }
}