.page-about{
  background-color:var(--walnut);
  background-image:var(--grain);
  color:var(--warm);
  padding-block:clamp(1.1rem,3vw,2rem) clamp(3rem,7vw,5.5rem);
}
.page-about p{
  color:rgba(251,246,234,.84);
  line-height:1.85;
  font-size:.98rem;
}
.page-about .breadcrumbs{margin-bottom:clamp(1.1rem,3vw,1.9rem);}
.page-about .breadcrumbs a,
.page-about .breadcrumbs__current{color:var(--liner);}

/* 整体骨架：移动端单列，桌面左侧抽屉轨道 */
.page-about .about-shell{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:1.5rem;
}
.page-about .rail-head{display:none;}
.page-about .rail-list{
  display:flex;
  gap:.4rem;
  overflow-x:auto;
  padding-bottom:.45rem;
  -webkit-overflow-scrolling:touch;
}
.page-about .rail-link{
  flex:0 0 auto;
  font-size:.8rem;
  letter-spacing:.03em;
  color:var(--liner);
  text-decoration:none;
  white-space:nowrap;
  padding:.5rem .85rem;
  border:1px solid rgba(182,122,61,.45);
  border-radius:var(--r-tag);
  background:rgba(233,216,180,.07);
  transition:color var(--dur),background-color var(--dur),transform var(--dur),border-color var(--dur);
}
.page-about .rail-link:hover,
.page-about .rail-link:focus-visible{
  color:var(--walnut);
  background:var(--liner);
  border-color:var(--liner);
  transform:translateY(-2px);
}
.page-about .rail-link:focus-visible{
  outline:2px solid var(--copper);
  outline-offset:2px;
}

/* 开篇 */
.page-about .about-hero{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:1.8rem;
}
.page-about .kicker{color:var(--copper);}
.page-about h1{
  font-family:var(--font-display);
  font-weight:800;
  font-size:clamp(1.85rem,4.6vw,3.15rem);
  line-height:1.2;
  letter-spacing:.01em;
  margin:.4rem 0 0;
  color:var(--warm);
}
.page-about .about-lede{
  margin-top:1rem;
  font-size:clamp(.98rem,1.6vw,1.08rem);
  line-height:1.85;
  color:rgba(251,246,234,.86);
  max-width:40ch;
}
.page-about .about-quote{
  margin:0 0 1.5rem;
  padding:clamp(1rem,3vw,1.7rem);
  border-left:3px solid var(--copper);
  border-radius:0 6px 6px 0;
  background:linear-gradient(160deg,rgba(233,216,180,.13),rgba(233,216,180,.03));
}
.page-about .about-quote p{
  font-family:var(--font-display);
  font-weight:700;
  font-size:clamp(1.2rem,2.7vw,1.7rem);
  line-height:1.5;
  color:var(--warm);
  margin:0 0 .7rem;
}
.page-about .about-quote footer{
  font-size:.8rem;
  line-height:1.7;
  color:rgba(251,246,234,.68);
}
.page-about .fact-grid{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:1px;
  background:rgba(182,122,61,.35);
  border:1px solid rgba(182,122,61,.35);
}
.page-about .fact{
  display:flex;
  flex-direction:column;
  gap:.15rem;
  padding:clamp(.85rem,2.4vw,1.25rem);
  background:var(--walnut-2);
}
.page-about .fact__num{
  font-family:var(--font-mono);
  font-size:clamp(1.4rem,3.4vw,2rem);
  line-height:1;
  color:var(--copper);
}
.page-about .fact__unit{
  font-size:.7rem;
  letter-spacing:.14em;
  color:rgba(251,246,234,.6);
}
.page-about .fact__label{
  margin-top:.35rem;
  font-size:.84rem;
  line-height:1.5;
  color:rgba(251,246,234,.85);
}

/* 图片 */
.page-about .about-fig{margin:1.5rem 0 0;}
.page-about .about-fig img{
  display:block;
  width:100%;
  max-width:100%;
  height:auto;
  border-radius:2px;
  object-fit:cover;
}
.page-about .about-fig--tall img{border:1px solid rgba(182,122,61,.4);}
.page-about .about-fig figcaption{
  margin-top:.6rem;
  font-size:.75rem;
  line-height:1.7;
  color:rgba(251,246,234,.6);
}

/* 章节通用 */
.page-about .sec{margin-top:clamp(2.4rem,6vw,4.4rem);}
.page-about .sec-head{
  display:flex;
  align-items:baseline;
  gap:.8rem;
  padding-top:.85rem;
  border-top:1px solid rgba(182,122,61,.4);
  margin-bottom:.85rem;
}
.page-about .sec-num{
  font-family:var(--font-mono);
  font-size:.78rem;
  letter-spacing:.1em;
  color:var(--copper);
}
.page-about .sec-title{
  margin:0;
  font-family:var(--font-display);
  font-weight:800;
  font-size:clamp(1.3rem,3vw,1.95rem);
  line-height:1.32;
  color:var(--warm);
}
.page-about .sec-lede{
  max-width:54ch;
  margin:0 0 1.3rem;
  font-size:.94rem;
  line-height:1.8;
  color:rgba(251,246,234,.74);
}

/* 整理方法 */
.page-about .method-grid{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:1.4rem;
}
.page-about .method-body p{margin:0 0 1.05rem;}
.page-about .method-body p:last-child{margin-bottom:0;}
.page-about .method-note{
  padding:clamp(1rem,3vw,1.5rem);
  background:var(--walnut-2);
  border:1px solid rgba(182,122,61,.4);
  border-radius:4px;
}
.page-about .method-note h3{
  margin:0 0 .8rem;
  font-family:var(--font-display);
  font-size:1rem;
  line-height:1.5;
  color:var(--copper);
}
.page-about .method-note ol{
  margin:0;
  padding-left:1.15rem;
  font-size:.88rem;
  line-height:1.8;
  color:rgba(251,246,234,.8);
}
.page-about .method-note li{margin-bottom:.55rem;}
.page-about .method-note li:last-child{margin-bottom:0;}

/* 使用场景 */
.page-about .scene-list{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  gap:1rem;
}
.page-about .scene{
  padding:clamp(.95rem,2.6vw,1.4rem) clamp(1rem,3vw,1.6rem);
  background:var(--paper);
  border-radius:3px;
  border-left:4px solid var(--grass);
  box-shadow:0 16px 30px -26px #000;
}
.page-about .scene:nth-child(2){border-left-color:var(--copper);}
.page-about .scene:nth-child(3){border-left-color:var(--score);}
.page-about .scene__when{
  display:block;
  font-family:var(--font-mono);
  font-size:.74rem;
  letter-spacing:.08em;
  color:var(--copper-ink);
}
.page-about .scene__title{
  margin:.25rem 0 .45rem;
  font-family:var(--font-display);
  font-size:1.08rem;
  line-height:1.45;
  color:var(--ink);
}
.page-about .scene p{
  margin:0;
  font-size:.92rem;
  line-height:1.8;
  color:#3a2a1e;
}

/* 团队 */
.page-about .team-grid{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:1.4rem;
}
.page-about .fold{border-bottom:1px solid rgba(182,122,61,.3);}
.page-about .fold:first-child{border-top:1px solid rgba(182,122,61,.3);}
.page-about .fold__summary{
  display:flex;
  align-items:baseline;
  gap:.6rem;
  padding:.85rem .15rem;
  cursor:pointer;
  list-style:none;
  font-family:var(--font-display);
  font-weight:700;
  font-size:1rem;
  line-height:1.55;
  color:var(--warm);
}
.page-about .fold__summary::-webkit-details-marker{display:none;}
.page-about .fold__summary::after{
  content:"+";
  margin-left:auto;
  padding-left:.6rem;
  font-family:var(--font-mono);
  font-size:1.1rem;
  color:var(--copper);
}
.page-about .fold[open] .fold__summary::after{content:"–";}
.page-about .fold__summary:focus-visible{
  outline:2px solid var(--copper);
  outline-offset:3px;
}
.page-about .fold__tag{
  flex:0 0 auto;
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.1em;
  color:var(--copper);
  border-bottom:1px solid rgba(182,122,61,.5);
}
.page-about .fold__body{padding:.1rem .15rem .95rem;}
.page-about .fold__body p{
  margin:0 0 .6rem;
  font-size:.9rem;
  line-height:1.8;
}
.page-about .fold__list{
  margin:0;
  padding-left:1.1rem;
  font-size:.87rem;
  line-height:1.85;
  color:rgba(251,246,234,.76);
}
.page-about .fold__list li{margin-bottom:.35rem;}
.page-about .fold__list li:last-child{margin-bottom:0;}

/* 版本轨道 */
.page-about .track{
  list-style:none;
  margin:0;
  padding:0 0 0 1.7rem;
  position:relative;
}
.page-about .track::before{
  content:"";
  position:absolute;
  left:.34rem;
  top:.5rem;
  bottom:.5rem;
  width:2px;
  background:linear-gradient(180deg,var(--copper),rgba(182,122,61,.12));
}
.page-about .track__item{
  position:relative;
  padding:.7rem 0;
  border-bottom:1px dashed rgba(182,122,61,.22);
}
.page-about .track__item::before{
  content:"";
  position:absolute;
  left:-1.47rem;
  top:1.02rem;
  width:.62rem;
  height:.62rem;
  border-radius:50%;
  background:var(--walnut);
  border:2px solid var(--copper);
  transition:background-color var(--dur),box-shadow var(--dur);
}
.page-about .track__item:hover::before,
.page-about .track__item:focus::before{
  background:var(--copper);
  box-shadow:0 0 0 4px rgba(182,122,61,.18);
}
.page-about .track__item:focus-visible{
  outline:2px solid var(--copper);
  outline-offset:4px;
  border-radius:3px;
}
.page-about .track__head{
  display:flex;
  flex-wrap:wrap;
  align-items:baseline;
  gap:.4rem .75rem;
}
.page-about .track__ver{
  font-family:var(--font-mono);
  font-size:.9rem;
  color:var(--warm);
}
.page-about .track__phase{
  font-size:.7rem;
  letter-spacing:.1em;
  color:var(--grass-lit);
  border:1px solid rgba(140,191,134,.45);
  border-radius:999px;
  padding:.1rem .55rem;
}
.page-about .track__sum{
  width:100%;
  font-size:.87rem;
  line-height:1.7;
  color:rgba(251,246,234,.72);
}
.page-about .track__more{
  display:grid;
  grid-template-rows:0fr;
  transition:grid-template-rows 220ms ease;
}
.page-about .track__more-inner{overflow:hidden;}
.page-about .track__more p{
  margin:0;
  padding-top:.45rem;
  max-width:56ch;
  font-size:.85rem;
  line-height:1.8;
  color:rgba(251,246,234,.66);
}
.page-about .track__item:hover .track__more,
.page-about .track__item:focus .track__more,
.page-about .track__item:focus-within .track__more{grid-template-rows:1fr;}

/* 标签体系 */
.page-about .tax-grid{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:1.4rem;
}
.page-about .tag-tree{
  list-style:none;
  margin:0;
  padding:0;
  counter-reset:layer;
}
.page-about .tag-tree li{
  position:relative;
  padding:.8rem 0 .8rem 2.4rem;
  border-bottom:1px solid rgba(182,122,61,.22);
}
.page-about .tag-tree li::before{
  counter-increment:layer;
  content:counter(layer,decimal-leading-zero);
  position:absolute;
  left:0;
  top:.92rem;
  font-family:var(--font-mono);
  font-size:.78rem;
  color:var(--copper);
}
.page-about .tag-tree__name{
  display:block;
  margin-bottom:.25rem;
  font-family:var(--font-display);
  font-weight:700;
  font-size:.98rem;
  color:var(--warm);
}
.page-about .tag-tree p{
  margin:0;
  font-size:.87rem;
  line-height:1.75;
  color:rgba(251,246,234,.76);
}

/* 服务范围 */
.page-about .reach{
  margin-top:clamp(2.4rem,6vw,4.4rem);
  padding:clamp(1.3rem,4vw,2.5rem);
  border:1px solid rgba(182,122,61,.42);
  border-radius:6px;
  background:linear-gradient(150deg,var(--walnut-2),var(--walnut) 72%);
}
.page-about .reach p{margin:0 0 1rem;max-width:60ch;}
.page-about .reach p:last-of-type{margin-top:1.4rem;}
.page-about .reach-facts{
  list-style:none;
  margin:1.2rem 0 0;
  padding:0;
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:1rem;
}
.page-about .reach-facts li{
  padding-top:.6rem;
  border-top:2px solid var(--copper);
  font-size:.87rem;
  line-height:1.75;
  color:rgba(251,246,234,.8);
}
.page-about .reach-facts b{
  display:block;
  margin-bottom:.3rem;
  font-family:var(--font-body);
  font-weight:700;
  font-size:1rem;
  color:var(--copper);
}
.page-about .cta-row{
  display:flex;
  flex-wrap:wrap;
  gap:.65rem;
  margin-top:1.5rem;
}

/* 平板与桌面 */
@media (min-width:760px){
  .page-about .scene:nth-child(2){margin-inline-start:6%;}
  .page-about .scene:nth-child(3){margin-inline-start:3%;}
  .page-about .reach-facts{grid-template-columns:repeat(3,minmax(0,1fr));}
}

@media (min-width:860px){
  .page-about .team-grid{
    grid-template-columns:minmax(0,6fr) minmax(0,5fr);
    gap:clamp(1.6rem,3.4vw,2.6rem);
    align-items:start;
  }
  .page-about .team-fig{position:sticky;top:1.2rem;margin-top:0;}
  .page-about .tax-grid{
    grid-template-columns:minmax(0,6fr) minmax(0,5fr);
    gap:clamp(1.6rem,3.4vw,2.6rem);
    align-items:start;
  }
  .page-about .tag-fig{margin-top:0;}
  .page-about .method-grid{
    grid-template-columns:minmax(0,6fr) minmax(0,5fr);
    gap:clamp(1.4rem,3vw,2.4rem);
    align-items:start;
  }
  .page-about .track__sum{width:auto;}
}

@media (min-width:900px){
  .page-about .about-hero{
    grid-template-columns:minmax(0,5fr) minmax(0,7fr);
    gap:clamp(1.6rem,3.5vw,3rem);
    align-items:start;
  }
}

@media (min-width:960px){
  .page-about .about-shell{
    grid-template-columns:minmax(150px,196px) minmax(0,1fr);
    column-gap:clamp(1.8rem,4vw,3.4rem);
    align-items:start;
  }
  .page-about .about-rail{
    position:sticky;
    top:1.2rem;
  }
  .page-about .rail-head{
    display:block;
    padding-bottom:.7rem;
    font-family:var(--font-display);
    font-size:.8rem;
    letter-spacing:.16em;
    color:var(--copper);
  }
  .page-about .rail-list{
    flex-direction:column;
    overflow:visible;
    gap:0;
    padding-bottom:0;
    border-top:1px solid rgba(182,122,61,.35);
  }
  .page-about .rail-link{
    padding:.62rem .7rem .62rem .9rem;
    border:0;
    border-bottom:1px solid rgba(182,122,61,.28);
    border-radius:0 10px 0 0;
    background:transparent;
    white-space:normal;
  }
  .page-about .rail-link:hover,
  .page-about .rail-link:focus-visible{
    transform:translateX(3px);
    border-bottom-color:var(--liner);
  }
}

@media (hover:none){
  .page-about .track__more{grid-template-rows:1fr;}
}

@media (prefers-reduced-motion:reduce){
  .page-about .rail-link,
  .page-about .track__item::before,
  .page-about .track__more{transition:none;}
}
<<<END>>>