.page-about{
  --about-rail: 104px;
  --about-gap: clamp(1.2rem, 3.4vw, 2.8rem);
  --about-dot: 11px;
  --about-glow-cyan: rgba(51, 240, 198, .13);
  --about-glow-gold: rgba(231, 180, 92, .15);
  padding-bottom: clamp(3rem, 8vw, 6rem);
}

/* ---------- 面包屑与标题区 ---------- */
.page-about .about-head{
  max-width: 64rem;
  padding-top: clamp(.6rem, 2vw, 1.4rem);
}

.page-about .breadcrumb{
  display: flex;
  align-items: center;
  gap: .55rem;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .16em;
  color: var(--mist);
}

.page-about .breadcrumb a{
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .24s var(--ease), border-color .24s var(--ease);
}

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

.page-about .breadcrumb [aria-current]{
  color: var(--paper-dim);
}

.page-about .crumb-sep{
  color: var(--line);
}

.page-about .about-head__eyebrow{
  margin: clamp(1.8rem, 5vw, 3.4rem) 0 0;
  color: var(--cyan);
}

.page-about .about-head__title{
  margin: .7rem 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.1rem, 7.6vw, 5.2rem);
  line-height: 1.02;
  letter-spacing: -.02em;
  color: var(--paper);
  text-wrap: balance;
}

.page-about .about-head__lede{
  margin: clamp(1.2rem, 3.4vw, 2rem) 0 0;
  max-width: 34em;
  font-size: clamp(1rem, 1.9vw, 1.12rem);
  line-height: 1.85;
  color: var(--paper-dim);
}

/* ---------- 顶部横幅 ---------- */
.page-about .about-banner{
  position: relative;
  margin: clamp(2.2rem, 5.5vw, 4.2rem) 0 0;
  overflow: hidden;
  background: var(--ink-800);
  clip-path: polygon(0 3.4%, 100% 0, 100% 100%, 0 96.6%);
}

.page-about .about-banner img{
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 6;
  object-fit: cover;
  filter: saturate(.7) contrast(1.06) brightness(.8);
}

.page-about .about-banner::after{
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
  opacity: .5;
}

/* ---------- 主体骨架：左侧刻线 + 右侧内容 ---------- */
.page-about .about-body{
  position: relative;
  margin-top: clamp(2.6rem, 6.5vw, 5.4rem);
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(2.6rem, 7vw, 4.6rem);
}

.page-about .about-sec{
  display: grid;
  grid-template-columns: 1fr;
  row-gap: .85rem;
}

.page-about .about-sec__rail{
  display: flex;
  align-items: center;
  gap: .55rem;
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .2em;
  color: var(--mist);
}

.page-about .rail-dot{
  flex: none;
  width: var(--about-dot);
  height: var(--about-dot);
  border-radius: 50%;
  background: var(--ink-900);
  border: 1px solid var(--cyan);
  box-shadow: 0 0 0 3px var(--about-glow-cyan);
}

.page-about .rail-no{
  color: var(--gold);
}

.page-about .rail-tag{
  color: var(--mist);
}

.page-about .about-sec__main > h2{
  margin: 0 0 clamp(.9rem, 2.2vw, 1.5rem);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.55rem, 3.8vw, 2.6rem);
  line-height: 1.14;
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-about .about-sec__main .prose{
  margin: 0 0 1.05em;
  color: var(--paper-dim);
}

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

.page-about .about-sec__main .prose a,
.page-about .about-sec__main .note a{
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(51, 240, 198, .4);
  transition: border-color .24s var(--ease);
}

.page-about .about-sec__main .prose a:hover,
.page-about .about-sec__main .note a:hover{
  border-bottom-color: var(--cyan);
}

/* ---------- 演进区插图 ---------- */
.page-about .about-ill{
  margin: clamp(1.6rem, 4vw, 2.6rem) 0 clamp(1.8rem, 4.4vw, 2.8rem);
}

.page-about .about-ill img{
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid var(--line);
  filter: saturate(.5) brightness(.78) contrast(1.05);
}

.page-about .media-frame__caption{
  margin-top: .75rem;
  font-size: .74rem;
  line-height: 1.85;
  color: var(--mist);
  max-width: 42em;
}

/* ---------- 演进时间轴 ---------- */
.page-about .about-tl{
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .about-tl::before{
  content: "";
  position: absolute;
  left: 5px;
  top: .9rem;
  bottom: .9rem;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan) 0%, var(--line) 24%, var(--line) 100%);
}

.page-about .tl-item{
  position: relative;
  padding-left: 1.95rem;
}

.page-about .tl-item + .tl-item{
  margin-top: .7rem;
}

.page-about .tl-item::after{
  content: "";
  position: absolute;
  left: 0;
  top: .95rem;
  width: var(--about-dot);
  height: var(--about-dot);
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 0 3px var(--about-glow-cyan);
  transition: background .24s var(--ease);
}

.page-about .tl-item--sync::after{
  background: var(--gold);
  box-shadow: 0 0 0 3px var(--about-glow-gold);
}

.page-about .about-tl summary{
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: .35rem .9rem;
  list-style: none;
  cursor: pointer;
  padding: .55rem .8rem .55rem .9rem;
  border-left: 2px solid transparent;
  border-radius: 0 4px 4px 0;
  transition: background .26s var(--ease), border-color .26s var(--ease);
}

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

.page-about .about-tl summary::after{
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: .9rem;
  color: var(--mist);
}

.page-about .about-tl details[open] > summary::after{
  content: "–";
  color: var(--cyan);
}

.page-about .about-tl summary:hover,
.page-about .about-tl summary:focus-visible{
  background: rgba(20, 48, 40, .5);
  border-left-color: var(--cyan);
}

.page-about .about-tl details[open] > summary{
  background: rgba(20, 48, 40, .34);
  border-left-color: var(--line);
}

.page-about .tl-season{
  font-family: var(--font-mono);
  font-size: .8rem;
  letter-spacing: .06em;
  color: var(--cyan);
}

.page-about .tl-item--sync .tl-season{
  color: var(--gold);
}

.page-about .tl-name{
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.04rem;
  letter-spacing: .01em;
  color: var(--paper);
}

.page-about .tl-body{
  padding: .1rem .8rem .85rem .9rem;
}

.page-about .tl-body p{
  margin: 0;
  max-width: 36em;
  font-size: .92rem;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 流程泳道 ---------- */
.page-about .lane-figure{
  margin: clamp(1.5rem, 3.6vw, 2.4rem) 0 clamp(1.6rem, 4vw, 2.6rem);
  padding: clamp(.8rem, 2vw, 1.4rem);
  background: rgba(20, 48, 40, .42);
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .lane-svg{
  display: block;
  width: 100%;
  min-width: 520px;
  height: auto;
}

.page-about .lane-svg text{
  font-family: var(--font-body);
  font-size: 13px;
  fill: var(--paper-dim);
}

.page-about .lane-svg .lane-label{
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  fill: var(--mist);
}

.page-about .lane-svg .lane{
  opacity: .6;
  transition: opacity .26s var(--ease);
}

.page-about .lane-svg .lane:hover{
  opacity: 1;
}

.page-about .lane-svg .lane rect{
  transition: fill .26s var(--ease), stroke .26s var(--ease);
}

.page-about .lane-svg .lane--edit rect{
  fill: rgba(51, 240, 198, .07);
  stroke: rgba(51, 240, 198, .45);
}

.page-about .lane-svg .lane--check rect{
  fill: rgba(169, 180, 190, .06);
  stroke: rgba(169, 180, 190, .42);
}

.page-about .lane-svg .lane--edit:hover rect{
  fill: rgba(51, 240, 198, .17);
}

.page-about .lane-svg .lane--check:hover rect{
  fill: rgba(169, 180, 190, .15);
}

.page-about .lane-caption{
  margin-top: .8rem;
  font-size: .72rem;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 编号步骤 ---------- */
.page-about .step-list{
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: clamp(.9rem, 2.4vw, 1.35rem);
}

.page-about .step{
  display: grid;
  grid-template-columns: 2.5rem minmax(0, 1fr);
  gap: .85rem;
  padding-top: .95rem;
  border-top: 1px solid var(--line);
}

.page-about .step__no{
  font-family: var(--font-mono);
  font-size: .88rem;
  letter-spacing: .08em;
  color: var(--gold);
  padding-top: .18rem;
}

.page-about .step__title{
  margin: 0 0 .45rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.06rem;
  letter-spacing: .01em;
  color: var(--paper);
}

.page-about .step__body p{
  margin: 0;
  max-width: 36em;
  font-size: .94rem;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 口径手册 ---------- */
.page-about .manual-grid{
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1.6rem, 4vw, 2.8rem);
}

.page-about .manual-figure{
  margin: 0;
}

.page-about .manual-figure img{
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  border: 1px solid var(--line);
  filter: saturate(.85) brightness(.82);
}

/* ---------- 覆盖范围 ---------- */
.page-about .cover-list{
  margin: 0 0 clamp(1.6rem, 4vw, 2.4rem);
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .cover-row{
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: baseline;
  gap: .6rem 1.2rem;
  padding: .95rem 0;
  border-bottom: 1px solid var(--line);
}

.page-about .cover-row dt{
  font-size: .84rem;
  letter-spacing: .06em;
  color: var(--mist);
}

.page-about .cover-row dd{
  margin: 0;
  font-size: .95rem;
  color: var(--paper-dim);
  text-align: right;
}

.page-about .cover-num{
  font-size: clamp(1.15rem, 2.6vw, 1.6rem);
  color: var(--gold);
  letter-spacing: -.01em;
}

/* ---------- 联系渠道 ---------- */
.page-about .reach-list{
  list-style: none;
  margin: 0 0 clamp(1.4rem, 3.4vw, 2rem);
  padding: 0;
}

.page-about .reach-item{
  display: grid;
  grid-template-columns: 1fr;
  row-gap: .25rem;
  padding: .95rem 0;
  border-bottom: 1px solid var(--line);
}

.page-about .reach-item:first-child{
  border-top: 1px solid var(--line);
}

.page-about .reach-k{
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .16em;
  color: var(--mist);
}

.page-about .reach-v{
  font-size: .96rem;
  line-height: 1.7;
  color: var(--paper);
  word-break: break-word;
}

.page-about .note{
  display: block;
  margin: 0 0 clamp(1.2rem, 3vw, 1.8rem);
  font-size: .82rem;
  line-height: 1.95;
  color: var(--mist);
  max-width: 42em;
}

.page-about .reach-action{
  display: flex;
  flex-wrap: wrap;
  gap: .7rem;
  margin: 0;
}

/* ---------- 平板及以上 ---------- */
@media (min-width: 900px){
  .page-about .about-body{
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    column-gap: var(--about-gap);
    row-gap: clamp(3.2rem, 6vw, 6rem);
  }

  .page-about .about-body::before{
    content: "";
    position: absolute;
    left: 5px;
    top: .9rem;
    bottom: .9rem;
    width: 1px;
    background: linear-gradient(180deg, transparent, var(--line) 8%, var(--line) 90%, transparent);
  }

  .page-about .about-sec{
    grid-column: 1 / -1;
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    column-gap: var(--about-gap);
    align-items: start;
    row-gap: 0;
  }

  .page-about .about-sec__rail{
    flex-direction: column;
    align-items: flex-start;
    gap: .45rem;
    padding-top: .3rem;
  }

  .page-about .manual-grid{
    grid-template-columns: minmax(0, 1.35fr) minmax(0, .85fr);
    align-items: start;
  }

  .page-about .reach-item{
    grid-template-columns: minmax(0, 15rem) minmax(0, 1fr);
    align-items: baseline;
    column-gap: 1.6rem;
  }
}

@media (min-width: 1180px){
  .page-about{
    --about-rail: 132px;
  }

  .page-about .about-body::before{
    left: 5px;
  }
}

@media (prefers-reduced-motion: reduce){
  .page-about .lane-svg .lane,
  .page-about .about-tl summary,
  .page-about .tl-item::after,
  .page-about .breadcrumb a{
    transition: none;
  }
}