.page-about{
  --about-rail-w: 104px;
  --about-gap: clamp(20px, 4vw, 60px);
  --about-num: clamp(46px, 10vw, 92px);
  --about-soft: #BFD0C9;
}

/* 首屏：文字建筑 */
.page-about .about-masthead{
  padding-block: clamp(24px, 5vw, 60px) clamp(32px, 6vw, 78px);
}

.page-about .about-title{
  margin: 0 0 clamp(18px, 2.6vw, 26px);
  max-width: 15ch;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(33px, 7.2vw, 82px);
  line-height: 1.02;
  letter-spacing: -0.015em;
  color: var(--paper);
  text-wrap: balance;
}

.page-about .about-lede{
  max-width: 34em;
  margin: 0 0 clamp(24px, 3.6vw, 36px);
  font-size: clamp(16px, 1.9vw, 19px);
  line-height: 1.88;
  color: var(--about-soft);
}

.page-about .about-facts{
  display: flex;
  flex-wrap: wrap;
  gap: 12px 0;
  margin: 0;
  padding: clamp(16px, 2.4vw, 22px) 0 0;
  list-style: none;
  border-top: 3px solid var(--line);
}

.page-about .about-fact{
  flex: 1 1 150px;
  padding-left: 12px;
  border-left: 3px solid var(--signal);
}

.page-about .about-fact-key{
  display: block;
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--mute);
}

.page-about .about-fact-val{
  display: block;
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: clamp(20px, 3vw, 27px);
  font-weight: 600;
  line-height: 1;
  color: var(--signal);
}

/* 章节骨架 */
.page-about .about-chapter{
  padding-block: clamp(38px, 7vw, 92px);
  border-bottom: 3px solid var(--line);
}

.page-about .about-chapter-grid{
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(10px, 2vw, 16px);
}

.page-about .about-rail{
  align-self: start;
}

.page-about .about-num{
  display: block;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: var(--about-num);
  line-height: .78;
  letter-spacing: -.02em;
  color: var(--pitch);
}

.page-about .about-body{
  min-width: 0;
}

.page-about .about-h2{
  margin: 0 0 clamp(14px, 2.2vw, 22px);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(26px, 4.2vw, 44px);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--paper);
  text-wrap: balance;
}

.page-about .about-body p{
  max-width: 34em;
  margin: 0 0 1.15em;
  line-height: 1.88;
  color: var(--about-soft);
}

.page-about .about-note{
  display: inline-block;
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  padding: 8px 14px;
  border: 2px solid var(--line);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--mute);
}

/* 图片框 */
.page-about .about-figure{
  margin: 0 0 clamp(24px, 3.6vw, 40px);
  border: 3px solid var(--line);
  box-shadow: var(--shadow-hard);
  background: var(--panel);
}

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

.page-about .about-figcap{
  display: block;
  padding: 10px 14px;
  border-top: 3px solid var(--line);
  font-size: 11px;
  letter-spacing: .1em;
  line-height: 1.6;
  color: var(--mute);
}

/* 版本轨道 SVG */
.page-about .route-track{
  display: block;
  width: 100%;
  height: auto;
  margin: 0 0 clamp(22px, 3vw, 34px);
}

/* 筛选按钮 */
.page-about .filter-bar{
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 clamp(20px, 3vw, 32px);
}

.page-about .filter-btn{
  padding: 9px 16px;
  border: 2px solid var(--line);
  background: var(--panel);
  color: var(--mute);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  cursor: pointer;
  transition: background .18s ease, color .18s ease, border-color .18s ease;
}

.page-about .filter-btn:hover{
  border-color: var(--signal-soft);
  color: var(--paper);
}

.page-about .filter-btn[aria-pressed="true"]{
  background: var(--signal);
  border-color: var(--signal);
  color: var(--ink);
  font-weight: 700;
}

/* 路线列表 */
.page-about .route-list{
  margin: 0;
  padding: 0 0 0 22px;
  list-style: none;
  border-left: 2px solid var(--line);
}

.page-about .route-item{
  position: relative;
  padding: 0 0 clamp(22px, 3vw, 32px);
}

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

.page-about .route-item::before{
  content: "";
  position: absolute;
  left: -27px;
  top: 7px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--signal);
}

.page-about .route-item[data-tags="当前"]::before{
  background: var(--live);
}

.page-about .route-ver{
  display: inline-block;
  margin-bottom: 8px;
  padding: 2px 8px;
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--live);
}

.page-about .route-title{
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: clamp(19px, 2.4vw, 25px);
  font-weight: 700;
  line-height: 1.2;
  color: var(--paper);
}

.page-about .route-text{
  max-width: 36em;
  margin: 0;
  line-height: 1.85;
  color: var(--about-soft);
}

/* 深蓝面板章节 */
.page-about .about-chapter--route{
  background: radial-gradient(900px 380px at 88% -10%, rgba(46, 204, 113, .13), transparent 70%);
}

.page-about .about-chapter--panel{
  background: var(--panel);
  border-top: 3px solid var(--line);
}

/* 冷白纸面章节 */
.page-about .about-chapter--paper{
  --about-soft: #24373E;
  background: var(--paper);
  color: var(--ink);
}

.page-about .about-chapter--paper .about-num{
  color: var(--pitch-deep);
}

.page-about .about-chapter--paper .about-h2{
  color: var(--ink);
}

.page-about .about-body--split .about-col{
  min-width: 0;
}

/* 数据摘录 */
.page-about .about-stats{
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 16px 18px;
  margin: clamp(20px, 3vw, 32px) 0 clamp(20px, 3vw, 30px);
  padding: 0;
  list-style: none;
}

.page-about .about-stat{
  padding-top: 10px;
  border-top: 3px solid var(--signal);
}

.page-about .about-stat-num{
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.6vw, 34px);
  font-weight: 600;
  line-height: 1;
  color: var(--signal);
}

.page-about .about-stat-label{
  display: block;
  margin-top: 9px;
  font-size: 12px;
  line-height: 1.6;
  letter-spacing: .06em;
  color: var(--mute);
}

.page-about .about-chapter--paper .about-stat{
  border-top-color: var(--pitch-deep);
}

.page-about .about-chapter--paper .about-stat-num{
  color: var(--ink);
}

.page-about .about-chapter--paper .about-stat-label{
  color: var(--line);
}

.page-about .about-chapter--panel .about-figure{
  margin-top: clamp(20px, 3vw, 32px);
}

/* 联系章节 */
.page-about .about-contact{
  display: grid;
  gap: 0;
  margin: clamp(18px, 2.6vw, 26px) 0 0;
  padding: 0;
  list-style: none;
  border-top: 2px solid var(--line);
}

.page-about .about-contact-item{
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 14px 0;
  border-bottom: 2px solid var(--line);
}

.page-about .about-contact-key{
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--mute);
}

.page-about .about-contact-val{
  font-family: var(--font-mono);
  font-size: clamp(15px, 1.8vw, 18px);
  line-height: 1.6;
  color: var(--paper);
  word-break: break-word;
}

.page-about .about-hint{
  margin: clamp(16px, 2.4vw, 22px) 0 0;
  padding-left: 14px;
  border-left: 3px solid var(--live);
  font-size: 14px;
  line-height: 1.8;
  color: var(--about-soft);
}

.page-about .about-links{
  margin: clamp(20px, 3vw, 30px) 0 0;
  font-size: 15px;
  line-height: 1.9;
  color: var(--about-soft);
}

.page-about .about-inline-link{
  color: var(--signal);
  text-decoration: none;
  border-bottom: 2px solid var(--signal);
}

.page-about .about-inline-link:hover,
.page-about .about-inline-link:focus-visible{
  color: var(--signal-soft);
  border-bottom-color: var(--signal-soft);
}

.page-about .about-inline-link:focus-visible{
  outline: 2px solid var(--live);
  outline-offset: 3px;
}

/* 窄屏兜底 */
@media (max-width: 619px){
  .page-about .about-figure{
    box-shadow: var(--shadow-soft);
  }

  .page-about .route-list{
    padding-left: 18px;
  }

  .page-about .route-item::before{
    left: -23px;
    width: 9px;
    height: 9px;
  }

  .page-about .about-body p,
  .page-about .route-text{
    max-width: none;
  }
}

/* 平板及以上：非对称编年两栏 */
@media (min-width: 760px){
  .page-about .about-body--split{
    display: grid;
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    gap: clamp(22px, 3.4vw, 40px);
    align-items: start;
  }

  .page-about .about-figure--side{
    margin-bottom: 0;
  }

  .page-about .about-contact-item{
    grid-template-columns: 122px minmax(0, 1fr);
    align-items: baseline;
    gap: 16px;
  }
}

@media (min-width: 900px){
  .page-about .about-chapter-grid{
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
  }

  .page-about .about-rail{
    position: sticky;
    top: calc(var(--header-h) + 30px);
  }
}

@media (min-width: 1100px){
  .page-about .about-chapter-grid{
    grid-template-columns: 132px minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce){
  .page-about .filter-btn{
    transition: none;
  }
}
<<<END>>>