.page-about{
  --ab-rail: 4.5rem;
  --ab-line: rgba(59,242,199,.22);
  --ab-band: #0A3A31;
  background: var(--bg);
  color: var(--mist);
}

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

/* ---------- 首屏 ---------- */

.page-about .ab-hero{
  position: relative;
  padding-block: 3.25rem 2.75rem;
  background:
    radial-gradient(130% 100% at 88% -10%, rgba(59,242,199,.13), transparent 58%),
    radial-gradient(95% 80% at -10% 110%, rgba(242,176,59,.08), transparent 62%);
}

.page-about .breadcrumb{
  display: flex;
  align-items: center;
  gap: .5rem;
  margin: 0 0 1.6rem;
  font-size: .8rem;
  letter-spacing: .05em;
  color: var(--grey);
}

.page-about .breadcrumb a{
  color: var(--grey);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.page-about .breadcrumb a:hover{
  color: var(--neon);
  border-bottom-color: var(--neon);
}

.page-about .ab-hero__eyebrow{
  margin: 0 0 .9rem;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .2em;
  color: var(--neon);
}

.page-about .ab-hero__title{
  margin: 0 0 1.35rem;
  max-width: 860px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2rem, 8.4vw, 4.2rem);
  line-height: 1.04;
  letter-spacing: -.015em;
  color: var(--mist);
}

.page-about .ab-hero__lead{
  margin: 0;
  max-width: 64ch;
  font-size: 1rem;
  line-height: 1.85;
  color: rgba(232,245,240,.84);
}

.page-about .ab-hero__facts{
  display: grid;
  grid-template-columns: repeat(2, minmax(0,1fr));
  gap: .75rem;
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-hero__facts li{
  padding: .95rem 1rem;
  border: 1px solid var(--hairline);
  border-radius: var(--r-md);
  background: rgba(10,58,49,.6);
}

.page-about .ab-fact__num{
  display: block;
  font-family: var(--font-mono);
  font-size: 1.55rem;
  line-height: 1.1;
  letter-spacing: -.01em;
  color: var(--neon);
}

.page-about .ab-fact__num em{
  font-style: normal;
  font-size: .62em;
  margin-left: .08em;
  color: var(--amber);
}

.page-about .ab-fact__label{
  display: block;
  margin-top: .3rem;
  font-size: .78rem;
  letter-spacing: .05em;
  color: var(--grey);
}

/* ---------- 章节骨架 ---------- */

.page-about .ab-chapter{
  padding-block: 3rem;
}

.page-about .ab-chapter--tint{
  background: var(--ab-band);
  border-block: 1px solid var(--hairline);
}

.page-about .ab-chapter__inner{
  display: grid;
  grid-template-columns: minmax(0,1fr);
  gap: 1.25rem;
}

.page-about .ab-chapter__rail{
  position: relative;
}

.page-about .ab-chapter__no{
  display: block;
  font-family: var(--font-mono);
  font-size: 1.9rem;
  line-height: 1;
  letter-spacing: .06em;
  color: rgba(59,242,199,.28);
}

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

.page-about .ab-chapter__title{
  margin: 0 0 .8rem;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.5rem, 4.8vw, 2.25rem);
  line-height: 1.16;
  letter-spacing: -.01em;
  color: var(--mist);
}

.page-about .ab-chapter__lead{
  margin: 0 0 1.6rem;
  max-width: 58ch;
  font-size: 1rem;
  line-height: 1.75;
  color: rgba(232,245,240,.86);
}

.page-about .ab-prose p{
  margin: 0 0 1.05rem;
  max-width: 68ch;
  font-size: .96rem;
  line-height: 1.85;
  color: var(--grey);
}

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

.page-about .ab-note{
  margin: 1.75rem 0 0;
  max-width: 68ch;
  font-size: .9rem;
  line-height: 1.8;
  color: var(--grey);
}

.page-about .ab-note a{
  color: var(--neon);
  text-decoration: none;
  border-bottom: 1px solid rgba(59,242,199,.4);
}

.page-about .ab-note a:hover{
  color: var(--neon-soft);
  border-bottom-color: var(--neon-soft);
}

/* ---------- 图片 ---------- */

.page-about .ab-figure{
  margin: 1.5rem 0 0;
}

.page-about .ab-figure--tight{
  margin-top: 0;
}

.page-about .ab-figure .media{
  border-radius: var(--r-lg);
  overflow: hidden;
}

.page-about .ab-figure .media__caption{
  margin-top: .75rem;
  font-size: .8rem;
  letter-spacing: .04em;
  color: var(--grey);
}

/* ---------- 版本时间线 ---------- */

.page-about .ab-timeline{
  position: relative;
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-timeline::before{
  content: "";
  position: absolute;
  left: 6px;
  top: .9rem;
  bottom: .9rem;
  width: 1px;
  background: linear-gradient(180deg, var(--neon), rgba(59,242,199,.05));
}

.page-about .ab-tl{
  position: relative;
  padding-left: 2rem;
  margin-bottom: .85rem;
}

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

.page-about .ab-tl::before{
  content: "";
  position: absolute;
  left: 1px;
  top: 1.5rem;
  width: 11px;
  height: 11px;
  box-sizing: border-box;
  border-radius: 50%;
  background: var(--bg-2);
  border: 2px solid var(--neon);
  z-index: 1;
}

.page-about .ab-chapter--tint .ab-tl::before{
  background: var(--bg-2);
}

.page-about .ab-tl__summary{
  display: grid;
  grid-template-columns: minmax(0,1fr) auto;
  align-items: center;
  gap: .5rem .9rem;
  padding: .95rem 1.1rem;
  list-style: none;
  cursor: pointer;
  border: 1px solid var(--hairline);
  border-radius: var(--r-lg);
  background: var(--bg-2);
  transition: background .2s var(--ease), border-color .2s var(--ease);
}

.page-about .ab-chapter--tint .ab-tl__summary{
  background: var(--bg);
}

.page-about .ab-tl__summary::-webkit-details-marker{
  display: none;
}

.page-about .ab-tl__summary:hover{
  border-color: rgba(59,242,199,.45);
}

.page-about .ab-tl__summary::after{
  content: "";
  grid-column: 2;
  grid-row: 1;
  width: 9px;
  height: 9px;
  margin-top: -4px;
  border-right: 2px solid var(--neon);
  border-bottom: 2px solid var(--neon);
  transform: rotate(45deg);
  transition: transform .22s var(--ease);
}

.page-about .ab-tl__item[open] > .ab-tl__summary::after{
  transform: rotate(225deg);
  margin-top: 4px;
}

.page-about .ab-tl__head{
  grid-column: 1;
  grid-row: 1;
  display: flex;
  align-items: baseline;
  gap: .7rem;
  flex-wrap: wrap;
}

.page-about .ab-tl__ver{
  font-size: 1.05rem;
  color: var(--neon);
}

.page-about .ab-tl__stage{
  padding: .12rem .58rem;
  border: 1px solid rgba(242,176,59,.42);
  border-radius: var(--r-pill);
  font-size: .7rem;
  letter-spacing: .12em;
  color: var(--amber);
  white-space: nowrap;
}

.page-about .ab-tl__name{
  grid-column: 1 / -1;
  grid-row: 2;
  font-size: .95rem;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .ab-tl__body{
  margin-top: .55rem;
  padding: .3rem 0 1rem 1.15rem;
  border-left: 2px solid rgba(59,242,199,.3);
}

.page-about .ab-tl__body p{
  margin: 0;
  font-size: .92rem;
  line-height: 1.82;
  color: var(--grey);
}

/* ---------- 数据流程 ---------- */

.page-about .ab-flow{
  display: grid;
  gap: 1rem;
  margin-top: .5rem;
}

.page-about .ab-step{
  position: relative;
  padding: 1.4rem 1.25rem 1.5rem;
  border: 1px solid var(--hairline);
  border-radius: var(--r-lg);
  background: var(--bg-2);
}

.page-about .ab-chapter--tint .ab-step{
  background: var(--bg);
}

.page-about .ab-step::before{
  content: "";
  position: absolute;
  top: -1px;
  left: 1.25rem;
  right: 1.25rem;
  height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--neon), rgba(59,242,199,0));
  opacity: .6;
}

.page-about .ab-step__no{
  display: inline-block;
  margin-bottom: .9rem;
  padding: .18rem .62rem;
  border-radius: var(--r-pill);
  background: var(--neon);
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .16em;
  color: var(--ink);
}

.page-about .ab-step__title{
  margin: 0 0 .55rem;
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--mist);
}

.page-about .ab-step__text{
  margin: 0;
  font-size: .93rem;
  line-height: 1.8;
  color: var(--grey);
}

/* ---------- 服务网络 ---------- */

.page-about .ab-network{
  display: grid;
  gap: 1.5rem;
  margin-top: .25rem;
}

.page-about .ab-cities{
  display: grid;
  gap: .85rem;
  margin: 1.6rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-city{
  padding: 1.1rem 1.05rem;
  border: 1px solid var(--hairline);
  border-radius: var(--r-md);
  background: var(--bg);
}

.page-about .ab-city__name{
  display: block;
  font-family: var(--font-mono);
  font-size: 1.15rem;
  letter-spacing: .06em;
  color: var(--neon);
}

.page-about .ab-city__role{
  display: block;
  margin-top: .2rem;
  font-size: .74rem;
  letter-spacing: .1em;
  color: var(--amber);
}

.page-about .ab-city__text{
  margin: .65rem 0 0;
  font-size: .89rem;
  line-height: 1.75;
  color: var(--grey);
}

/* ---------- 质量体系 ---------- */

.page-about .ab-quality{
  display: grid;
  gap: 1rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-quality li{
  display: grid;
  grid-template-columns: 2.3rem minmax(0,1fr);
  gap: .85rem;
  padding-top: 1rem;
  border-top: 1px solid var(--hairline);
}

.page-about .ab-quality__no{
  padding-top: .18rem;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .1em;
  color: var(--amber);
}

.page-about .ab-quality h3{
  margin: 0 0 .4rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--mist);
}

.page-about .ab-quality p{
  margin: 0;
  font-size: .92rem;
  line-height: 1.8;
  color: var(--grey);
}

/* ---------- 路线折叠面板 ---------- */

.page-about .ab-acc{
  display: grid;
  gap: .75rem;
  margin-top: 0;
}

.page-about .ab-acc__item{
  overflow: hidden;
  border: 1px solid var(--hairline);
  border-radius: var(--r-lg);
  background: rgba(10,58,49,.55);
}

.page-about .ab-acc__summary{
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.05rem 1.15rem;
  list-style: none;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 600;
  color: var(--mist);
  transition: color .2s var(--ease);
}

.page-about .ab-acc__summary::-webkit-details-marker{
  display: none;
}

.page-about .ab-acc__summary:hover{
  color: var(--neon);
}

.page-about .ab-acc__plus{
  position: relative;
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  border: 1px solid rgba(59,242,199,.5);
  border-radius: 50%;
}

.page-about .ab-acc__plus::before,
.page-about .ab-acc__plus::after{
  content: "";
  position: absolute;
  top: 50%;
  left: 5px;
  right: 5px;
  height: 1.5px;
  background: var(--neon);
  transform: translateY(-50%);
}

.page-about .ab-acc__plus::after{
  transform: translateY(-50%) rotate(90deg);
  transition: transform .22s var(--ease), opacity .22s var(--ease);
}

.page-about .ab-acc__item[open] .ab-acc__plus::after{
  transform: translateY(-50%) rotate(0deg);
  opacity: 0;
}

.page-about .ab-acc__body{
  padding: 0 1.15rem 1.2rem;
}

.page-about .ab-acc__body p{
  margin: 0;
  max-width: 68ch;
  font-size: .93rem;
  line-height: 1.82;
  color: var(--grey);
}

.page-about .ab-cta{
  margin: 2rem 0 0;
  padding: 1.25rem 1.35rem;
  border: 1px solid rgba(59,242,199,.3);
  border-radius: var(--r-lg);
  background: linear-gradient(120deg, rgba(59,242,199,.09), rgba(242,176,59,.06));
  font-size: .94rem;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .ab-cta a{
  color: var(--neon);
  text-decoration: none;
  border-bottom: 1px solid rgba(59,242,199,.45);
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.page-about .ab-cta a:hover{
  color: var(--neon-soft);
  border-bottom-color: var(--neon-soft);
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px){
  .page-about .ab-hero{
    padding-block: 4rem 3.25rem;
  }

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

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

@media (min-width: 880px){
  .page-about .ab-chapter{
    padding-block: 4rem;
  }

  .page-about .ab-chapter__inner{
    grid-template-columns: var(--ab-rail) minmax(0,1fr);
    gap: 2.75rem;
  }

  .page-about .ab-chapter__rail{
    border-left: 1px solid var(--ab-line);
    padding-left: 1rem;
  }

  .page-about .ab-chapter__no{
    font-size: 2.1rem;
  }

  .page-about .ab-flow{
    grid-template-columns: repeat(3, minmax(0,1fr));
    gap: 1.25rem;
  }

  .page-about .ab-network{
    grid-template-columns: minmax(0,1.05fr) minmax(0,.95fr);
    gap: 2.25rem;
    align-items: start;
  }

  .page-about .ab-quality{
    grid-template-columns: repeat(2, minmax(0,1fr));
    gap: 1.1rem 1.75rem;
  }
}

@media (min-width: 1080px){
  .page-about .ab-hero{
    padding-block: 4.75rem 3.75rem;
  }

  .page-about .ab-hero__lead{
    font-size: 1.05rem;
  }
}

@media (prefers-reduced-motion: reduce){
  .page-about .ab-tl__summary::after,
  .page-about .ab-acc__plus::after,
  .page-about .ab-tl__summary,
  .page-about .ab-acc__summary{
    transition: none;
  }
}
<<<END>>>