.page-about{
  --about-line:rgba(169,183,176,.2);
  background:
    radial-gradient(120% 70% at 88% -8%, rgba(57,242,208,.10), transparent 62%),
    var(--ink-900);
  color:var(--paper);
  padding-block:0 clamp(46px,7vw,92px);
}

.page-about .crumbs{margin-top:clamp(14px,2.4vw,24px);}

/* ---------- 首屏 ---------- */
.page-about .about-hero{
  display:grid;
  gap:clamp(22px,3.6vw,44px);
  padding-block:clamp(18px,3vw,32px) clamp(30px,5vw,58px);
  align-items:end;
}

.page-about .about-hero__title{
  margin:14px 0 0;
  font-family:var(--font-display);
  font-weight:400;
  font-size:clamp(2rem,6.1vw,3.85rem);
  line-height:1.08;
  letter-spacing:-.015em;
  color:var(--paper);
}

.page-about .about-hero__dek{
  margin:18px 0 0;
  max-width:58ch;
  font-size:clamp(.9rem,2.3vw,1rem);
  line-height:1.82;
  color:rgba(242,230,206,.76);
}

.page-about .about-hero__marks{
  display:flex;
  flex-wrap:wrap;
  gap:8px 10px;
  list-style:none;
  margin:22px 0 0;
  padding:0;
}

.page-about .about-hero__marks li{
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.06em;
  padding:7px 12px;
  border-radius:var(--pill);
  border:1px solid var(--line-strong);
  color:var(--mist);
}

.page-about .about-hero__marks li:first-child{
  color:var(--cyan);
  border-color:rgba(57,242,208,.42);
}

.page-about .about-hero__fig{margin:0;max-width:100%;}
.page-about .about-hero__fig img{
  display:block;
  width:100%;
  height:auto;
  border-radius:var(--r-xl);
  border:1px solid var(--line);
  object-fit:cover;
}
.page-about .about-hero__fig .figure__caption{
  margin-top:12px;
  font-size:.74rem;
  letter-spacing:.08em;
  color:var(--mist);
}

/* ---------- 三栏正文骨架 ---------- */
.page-about .about-body{
  display:grid;
  gap:clamp(26px,4vw,46px);
  padding-block:clamp(26px,4vw,42px);
  border-top:1px solid var(--about-line);
  min-width:0;
}

.page-about .about-toc,
.page-about .about-stream,
.page-about .about-margin{min-width:0;}

.page-about .about-toc__label{
  margin:0 0 12px;
  font-size:.68rem;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--mist);
}

.page-about .about-toc__list{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  gap:2px;
}

.page-about .about-toc__list a{
  display:flex;
  align-items:baseline;
  gap:10px;
  min-height:var(--tap);
  padding:8px 8px 8px 0;
  font-size:.86rem;
  color:var(--mist);
  text-decoration:none;
  border-bottom:1px solid var(--about-line);
  transition:color var(--dur) var(--ease),padding-left var(--dur) var(--ease);
}

.page-about .about-toc__list a:hover,
.page-about .about-toc__list a:focus-visible{
  color:var(--cyan);
  padding-left:6px;
}

.page-about .about-toc__list .num{
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.08em;
  color:var(--amber);
  flex:none;
}

/* ---------- 章节 ---------- */
.page-about .about-sec{
  padding-block:clamp(24px,3.6vw,38px);
  border-top:1px solid var(--about-line);
  scroll-margin-top:96px;
}

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

.page-about .about-sec__head{
  display:flex;
  align-items:baseline;
  gap:12px;
  margin-bottom:16px;
}

.page-about .about-sec__num{
  font-family:var(--font-mono);
  font-size:.78rem;
  letter-spacing:.1em;
  color:var(--orange);
  flex:none;
}

.page-about .about-sec h2{
  margin:0;
  font-family:var(--font-display);
  font-weight:600;
  font-size:clamp(1.3rem,3.4vw,1.92rem);
  line-height:1.26;
  letter-spacing:-.01em;
  color:var(--paper);
}

.page-about .about-sec p{
  margin:0 0 14px;
  max-width:66ch;
  font-size:.92rem;
  line-height:1.82;
  color:rgba(242,230,206,.8);
}

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

.page-about .about-lead-list{
  list-style:none;
  margin:18px 0 14px;
  padding:0;
  display:grid;
  gap:12px;
}

.page-about .about-lead-list li{
  display:grid;
  gap:6px;
  padding:14px 16px;
  border-radius:var(--r-md);
  background:var(--panel);
  border:1px solid var(--about-line);
  border-left:3px solid var(--orange);
  transition:transform var(--dur) var(--ease),box-shadow var(--dur) var(--ease);
}

.page-about .about-lead-list li:hover{
  transform:translateY(-2px);
  box-shadow:0 10px 22px -14px rgba(0,0,0,.85);
}

.page-about .about-lead-list h3{
  margin:0;
  font-size:.95rem;
  font-weight:700;
  letter-spacing:.01em;
  color:var(--paper);
}

.page-about .about-sec .about-lead-list p{
  margin:0;
  font-size:.85rem;
  line-height:1.75;
  color:rgba(242,230,206,.72);
  max-width:60ch;
}

.page-about .about-fig{margin:0 0 20px;}
.page-about .about-fig img{
  display:block;
  width:100%;
  height:auto;
  border-radius:var(--r-lg);
  border:1px solid var(--about-line);
  object-fit:cover;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline{
  list-style:none;
  margin:20px 0 0;
  padding:0;
  display:grid;
}

.page-about .about-step{
  position:relative;
  display:grid;
  grid-template-columns:auto minmax(0,1fr);
  gap:14px;
  padding:0 0 20px 18px;
  border-left:1px solid var(--line-strong);
}

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

.page-about .about-step::before{
  content:"";
  position:absolute;
  left:-5px;
  top:6px;
  width:8px;
  height:8px;
  border-radius:50%;
  background:var(--ink-900);
  border:2px solid var(--amber);
  transition:background var(--dur) var(--ease),transform var(--dur) var(--ease);
}

.page-about .about-step:hover::before{
  background:var(--amber);
  transform:scale(1.3);
}

.page-about .about-step__v{
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.08em;
  color:var(--amber);
  padding-top:3px;
  min-width:42px;
}

.page-about .about-step__body h3{
  margin:0 0 5px;
  font-size:.94rem;
  font-weight:700;
  color:var(--paper);
}

.page-about .about-sec .about-step__body p{
  margin:0;
  font-size:.85rem;
  line-height:1.74;
  color:rgba(242,230,206,.7);
  max-width:58ch;
}

/* ---------- 旁注卡 ---------- */
.page-about .about-margin{
  display:grid;
  gap:16px;
  align-content:start;
}

.page-about .about-note{
  background:var(--paper);
  color:var(--brown);
  border-radius:var(--r-lg);
  padding:16px 16px 18px;
  border:1px solid rgba(42,32,24,.14);
}

.page-about .about-note__title{
  margin:0 0 12px;
  font-size:.66rem;
  font-weight:700;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:rgba(42,32,24,.58);
}

.page-about .about-note__list{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  gap:9px;
}

.page-about .about-note__list li{
  display:flex;
  justify-content:space-between;
  align-items:baseline;
  gap:10px;
  font-size:.82rem;
  line-height:1.5;
  padding-bottom:9px;
  border-bottom:1px solid rgba(42,32,24,.14);
}

.page-about .about-note__list li:last-child{
  border-bottom:0;
  padding-bottom:0;
}

.page-about .about-note__list .num{
  font-family:var(--font-mono);
  font-size:.86rem;
  letter-spacing:.04em;
  color:var(--brown);
}

.page-about .about-note__text{
  margin:0 0 10px;
  font-size:.82rem;
  line-height:1.7;
  color:rgba(42,32,24,.82);
}

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

.page-about .about-note a{
  color:var(--brown);
  text-decoration:underline;
  text-underline-offset:3px;
  text-decoration-thickness:1px;
}

.page-about .about-note a:hover,
.page-about .about-note a:focus-visible{color:#B8420E;}

/* ---------- 收尾 ---------- */
.page-about .about-next{
  margin-top:clamp(16px,3vw,28px);
  padding:clamp(20px,3.4vw,32px);
  border-radius:var(--r-xl);
  background:var(--panel);
  border:1px solid var(--line-amber);
  border-top:3px solid var(--orange);
}

.page-about .about-next h2{
  margin:0 0 10px;
  font-family:var(--font-display);
  font-weight:600;
  font-size:clamp(1.2rem,3vw,1.6rem);
  letter-spacing:-.01em;
  color:var(--paper);
}

.page-about .about-next p{
  margin:0 0 18px;
  max-width:62ch;
  font-size:.88rem;
  line-height:1.78;
  color:rgba(242,230,206,.74);
}

.page-about .about-next__links{
  list-style:none;
  margin:0;
  padding:0;
  display:flex;
  flex-wrap:wrap;
  gap:10px;
}

/* ---------- 响应式 ---------- */
@media (min-width:640px){
  .page-about .about-lead-list{gap:14px;}
  .page-about .about-next__links{gap:12px;}
}

@media (min-width:880px){
  .page-about .about-hero{
    grid-template-columns:minmax(0,1.04fr) minmax(0,.96fr);
  }
}

@media (min-width:940px){
  .page-about .about-body{
    grid-template-columns:186px minmax(0,1fr) 236px;
    gap:clamp(24px,3vw,44px);
  }
  .page-about .about-toc{
    position:sticky;
    top:92px;
    align-self:start;
  }
  .page-about .about-margin{gap:18px;}
  .page-about .about-lead-list li{padding:16px 18px;}
}

@media (min-width:1120px){
  .page-about .about-body{
    grid-template-columns:196px minmax(0,1fr) 260px;
  }
  .page-about .about-hero__fig{margin-top:6px;}
}

@media (prefers-reduced-motion:reduce){
  .page-about .about-lead-list li:hover{transform:none;}
  .page-about .about-step:hover::before{transform:none;}
  .page-about .about-toc__list a:hover,
  .page-about .about-toc__list a:focus-visible{padding-left:0;}
}