.page-about {
  --about-rail: 80px;
  --about-line: rgba(20, 18, 15, .14);
  display: block;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.8;
  overflow-x: hidden;
}

.page-about * {
  box-sizing: border-box;
}

/* ---------- 页首 ---------- */

.page-about .about-masthead {
  position: relative;
  padding: 0 0 20px;
  background:
    radial-gradient(120% 100% at 88% -20%, rgba(201, 162, 39, .22), transparent 62%),
    radial-gradient(90% 80% at 4% 8%, rgba(183, 51, 42, .12), transparent 66%),
    var(--paper);
}

.page-about .about-masthead::before {
  content: "";
  display: block;
  height: 5px;
  background: linear-gradient(90deg, var(--clay) 0%, var(--gold) 42%, var(--vermilion) 74%, var(--volt) 100%);
}

.page-about .breadcrumb {
  padding: 22px 0 0;
}

.page-about .about-hero {
  padding: 30px 0 16px;
}

.page-about .about-hero__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 14px;
  margin: 0 0 20px;
}

.page-about .about-hero__stamp {
  display: inline-block;
  padding: 5px 14px;
  border: 1px solid var(--line-gold);
  border-radius: 999px;
  background: rgba(201, 162, 39, .12);
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .18em;
  color: var(--brown-gold);
}

.page-about .about-hero__since {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: rgba(20, 18, 15, .48);
}

.page-about h1 {
  max-width: 18em;
  margin: 0;
  font-size: clamp(34px, 8.6vw, 84px);
  font-weight: 900;
  line-height: 1.06;
  letter-spacing: -.02em;
  color: var(--ink);
  overflow-wrap: break-word;
}

.page-about .about-hero__lead {
  max-width: 640px;
  margin: 24px 0 0;
  font-size: 17px;
  line-height: 1.85;
  color: var(--ink-soft);
}

/* ---------- 章节骨架 ---------- */

.page-about .about-flow {
  padding-top: 6px;
  padding-bottom: 6px;
}

.page-about .about-chapter {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
  padding: 44px 0;
  border-top: 1px solid var(--about-line);
}

.page-about .about-flow > .about-chapter:first-child {
  border-top: 0;
  padding-top: 34px;
}

.page-about .about-rail {
  display: flex;
  align-items: center;
}

.page-about .about-rail__num {
  display: inline-flex;
  align-items: center;
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--brown-gold);
}

.page-about .about-rail__num::before {
  content: "";
  display: inline-block;
  width: 8px;
  height: 8px;
  margin-right: 9px;
  border-radius: 50%;
  background: var(--gold);
  vertical-align: middle;
}

.page-about .about-h2 {
  margin: 0 0 18px;
  font-size: clamp(24px, 5vw, 40px);
  font-weight: 900;
  line-height: 1.22;
  letter-spacing: -.015em;
  color: var(--ink);
}

.page-about .about-body p {
  max-width: 640px;
  margin: 0 0 18px;
  color: var(--ink-soft);
}

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

.page-about .about-body strong {
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-body a {
  color: var(--volt);
  text-decoration: none;
  border-bottom: 1px solid rgba(61, 107, 255, .35);
  transition: border-color .2s var(--ease), color .2s var(--ease);
}

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

/* ---------- 时间线 ---------- */

.page-about .about-timeline {
  position: relative;
  margin: 28px 0 0;
  padding: 0 0 0 24px;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 14px;
  width: 2px;
  background: linear-gradient(180deg, var(--clay), var(--gold) 52%, rgba(201, 162, 39, .14));
}

.page-about .about-timeline__item {
  position: relative;
}

.page-about .about-timeline__item + .about-timeline__item {
  margin-top: 4px;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -22px;
  top: 15px;
  width: 10px;
  height: 10px;
  border: 2px solid var(--gold);
  border-radius: 50%;
  background: var(--paper);
}

.page-about .about-stage {
  border-bottom: 1px dashed var(--about-line);
}

.page-about .about-stage summary {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 12px;
  padding: 13px 30px 13px 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-stage summary::marker {
  content: "";
}

.page-about .about-stage summary::after {
  content: "+";
  position: absolute;
  right: 2px;
  top: 13px;
  font-family: var(--mono);
  font-size: 17px;
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
  transition: transform .25s var(--ease);
}

.page-about .about-stage[open] summary::after {
  transform: rotate(45deg);
}

.page-about .about-stage__tag {
  flex: none;
  padding: 2px 10px;
  border: 1px solid var(--line-gold);
  border-radius: 999px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--brown-gold);
  white-space: nowrap;
}

.page-about .about-stage__name {
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-stage__desc {
  max-width: 620px;
  margin: 0 0 16px;
  padding-right: 26px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink-soft);
}

/* ---------- 图 ---------- */

.page-about .about-figure {
  margin: 32px 0 0;
  border-top: 4px solid var(--clay);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: 0 0 var(--radius) var(--radius);
  background: linear-gradient(135deg, var(--paper-2), rgba(201, 162, 39, .16));
}

.page-about .about-figure figcaption {
  margin-top: 12px;
  padding-left: 11px;
  border-left: 2px solid var(--gold);
  font-family: var(--mono);
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: .04em;
  color: rgba(20, 18, 15, .5);
}

.page-about .about-figure--info img {
  border-radius: var(--radius);
}

/* ---------- 引文 ---------- */

.page-about .about-pull {
  max-width: 620px;
  margin: 36px 0 32px;
  padding: 8px 0 8px 22px;
  border-left: 3px solid var(--gold);
  font-size: clamp(22px, 5vw, 40px);
  font-weight: 900;
  line-height: 1.36;
  letter-spacing: -.01em;
  color: var(--ink);
  background: linear-gradient(90deg, rgba(201, 162, 39, .12), transparent 72%);
}

/* ---------- 产品线 ---------- */

.page-about .about-lines {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
  margin: 28px 0 30px;
}

.page-about .about-line {
  position: relative;
  padding-top: 18px;
  border-top: 3px solid var(--about-line);
}

.page-about .about-line--a {
  border-top-color: var(--gold);
}

.page-about .about-line--b {
  border-top-color: var(--jade);
}

.page-about .about-line--c {
  border-top-color: var(--clay);
}

.page-about .about-line h3 {
  margin: 12px 0 8px;
  font-size: 19px;
  font-weight: 800;
  line-height: 1.35;
  color: var(--ink);
}

.page-about .about-line p {
  margin: 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink-soft);
}

/* ---------- 深色体量带 ---------- */

.page-about .about-band {
  margin-top: 30px;
  padding: 52px 0 56px;
  background:
    radial-gradient(90% 70% at 12% -10%, rgba(201, 162, 39, .22), transparent 62%),
    radial-gradient(70% 60% at 96% 110%, rgba(61, 107, 255, .16), transparent 68%),
    var(--rock);
  color: var(--paper);
}

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

.page-about .about-band__lead {
  max-width: 620px;
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(246, 241, 231, .72);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px 20px;
  margin-top: 32px;
  padding-top: 28px;
  border-top: 1px solid rgba(246, 241, 231, .18);
}

.page-about .about-stats .stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}

.page-about .about-stats .stat__num {
  font-family: var(--mono);
  font-size: clamp(26px, 5.6vw, 42px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -.01em;
  color: var(--gold);
  overflow-wrap: break-word;
}

.page-about .about-stats .stat__lab {
  font-size: 13px;
  letter-spacing: .04em;
  color: rgba(246, 241, 231, .62);
}

.page-about .about-band .about-figure {
  margin-top: 44px;
  border-top-color: var(--gold);
}

.page-about .about-band .about-figure figcaption {
  border-left-color: var(--gold);
  color: rgba(246, 241, 231, .6);
}

/* ---------- 收束与行动 ---------- */

.page-about .about-chapter--last {
  padding-bottom: 30px;
}

.page-about .about-cta {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  padding: 40px 0 76px;
  border-top: 1px solid var(--about-line);
}

.page-about .about-cta__lead p {
  max-width: 560px;
  margin: 0;
  color: var(--ink-soft);
}

.page-about .about-cta__acts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 平板 ---------- */

@media (min-width: 720px) {
  .page-about .about-lines {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 28px 26px;
  }

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

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: end;
    gap: 40px;
  }
}

/* ---------- 桌面长卷 ---------- */

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 46px 0 26px;
  }

  .page-about .about-chapter {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 0 44px;
    padding: 76px 0;
  }

  .page-about .about-flow > .about-chapter:first-child {
    padding-top: 44px;
  }

  .page-about .about-rail {
    display: block;
    position: relative;
    padding-top: 5px;
  }

  .page-about .about-rail::before {
    content: "";
    position: absolute;
    left: 4px;
    top: 34px;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, rgba(201, 162, 39, .5), rgba(201, 162, 39, .04));
  }

  .page-about .about-chapter--last .about-rail::before {
    bottom: 40%;
  }

  .page-about .about-rail__num {
    position: relative;
    display: block;
    padding-left: 26px;
    font-size: 15px;
  }

  .page-about .about-rail__num::before {
    position: absolute;
    left: 0;
    top: 7px;
    width: 10px;
    height: 10px;
    margin: 0;
    box-shadow: 0 0 0 4px rgba(201, 162, 39, .16);
  }

  .page-about .about-lines {
    grid-template-columns: 1.15fr .95fr 1.05fr;
    align-items: start;
    gap: 30px;
    margin: 34px 0 36px;
  }

  .page-about .about-line--b {
    margin-top: 40px;
  }

  .page-about .about-line--c {
    margin-top: 82px;
  }

  .page-about .about-figure--offset {
    width: 78%;
    margin-left: auto;
    margin-right: 4%;
  }

  .page-about .about-band {
    padding: 68px 0 72px;
  }

  .page-about .about-band .about-figure--info {
    width: 74%;
    margin-top: 52px;
  }

  .page-about .about-cta {
    padding: 56px 0 96px;
  }
}

/* ---------- 无障碍动效 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-about .about-stage summary::after {
    transition: none;
  }

  .page-about .about-body a {
    transition: none;
  }
}