.page-about {
  --about-rail-w: 236px;
  --about-gap: 48px;
  display: block;
  scroll-behavior: smooth;
}

.page-about a:focus-visible,
.page-about summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 24px 0 44px;
  border-bottom: 2px solid var(--line-strong);
  background:
    radial-gradient(120% 90% at 88% 0%, rgba(56, 242, 208, .12), transparent 62%),
    repeating-linear-gradient(180deg, rgba(138, 143, 134, .07) 0 1px, transparent 1px 5px),
    linear-gradient(168deg, var(--ink-lift) 0%, var(--ink) 64%);
}

.page-about .about-hero__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  margin-top: 20px;
  align-items: end;
}

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

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-sans);
  font-weight: 200;
  font-size: clamp(2.1rem, 8.2vw, 4.3rem);
  line-height: 1.05;
  letter-spacing: -.025em;
  color: var(--paper);
  overflow-wrap: break-word;
}

.page-about .about-hero__lede {
  max-width: 46ch;
  margin: 18px 0 0;
  font-size: clamp(.94rem, 2.6vw, 1.02rem);
  line-height: 1.72;
  color: rgba(242, 237, 227, .82);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.page-about .about-hero__figure {
  margin: 0;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 26px), calc(100% - 26px) 100%, 0 100%);
}

.page-about .about-hero__stats {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 32px 0 0;
  padding: 1px;
  border: 2px solid var(--line-strong);
  background: var(--line-strong);
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 12px 12px 14px;
  background: var(--ink);
}

.page-about .about-stat__num {
  font-family: var(--font-mono);
  font-size: clamp(1.2rem, 4.4vw, 1.6rem);
  line-height: 1;
  letter-spacing: .02em;
  color: var(--cyan);
}

.page-about .about-stat__key {
  font-size: .72rem;
  letter-spacing: .08em;
  color: var(--stone);
}

/* ---------- 分屏骨架 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
  padding-top: 40px;
  padding-bottom: 18px;
}

.page-about .about-rail {
  display: none;
  min-width: 0;
}

.page-about .about-rail__inner {
  position: sticky;
  top: calc(var(--header-h) + 20px);
}

.page-about .about-rail__title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: .66rem;
  letter-spacing: .18em;
  color: var(--stone);
}

.page-about .about-rail__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0 0 26px;
  padding: 0;
}

.page-about .about-rail__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 8px 10px 8px 12px;
  border-left: 2px solid var(--line);
  color: var(--stone);
  text-decoration: none;
  font-size: .86rem;
  line-height: 1.4;
  transition: color .18s var(--ease), border-color .18s var(--ease), background .18s var(--ease);
}

.page-about .about-rail__link .mono {
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .1em;
  color: var(--clay);
  transition: color .18s var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible,
.page-about .about-rail__link.is-active {
  color: var(--cyan-soft);
  border-left-color: var(--cyan);
  background: rgba(56, 242, 208, .07);
}

.page-about .about-rail__link.is-active .mono {
  color: var(--cyan);
}

.page-about .about-scale {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 6px;
}

.page-about .about-scale__item {
  display: block;
  padding: 7px 2px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .04em;
  color: var(--paper);
  text-decoration: none;
  border: 1px solid var(--line-strong);
  transition: border-color .18s var(--ease), color .18s var(--ease), background .18s var(--ease);
}

.page-about .about-scale__item:hover,
.page-about .about-scale__item:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan-soft);
  background: rgba(56, 242, 208, .08);
}

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

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  margin-bottom: 66px;
  scroll-margin-top: calc(var(--header-h) + 22px);
}

.page-about .about-sec__head {
  border-top: 2px solid var(--line-strong);
  padding-top: 16px;
  margin-bottom: 24px;
}

.page-about .about-sec__num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .18em;
  color: var(--cyan);
  border: 1px solid var(--line-strong);
  padding: 2px 8px;
  margin-bottom: 14px;
}

.page-about .about-sec__title {
  margin: 0;
  font-size: clamp(1.4rem, 4.6vw, 2.05rem);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -.015em;
  color: var(--paper);
}

.page-about .about-sec__lede {
  max-width: 58ch;
  margin: 12px 0 0;
  font-size: .92rem;
  line-height: 1.72;
  color: rgba(242, 237, 227, .74);
}

.page-about .about-sec__media {
  margin: 0 0 22px;
}

/* ---------- 时间线 ---------- */
.page-about .timeline {
  list-style: none;
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
}

.page-about .timeline__item {
  position: relative;
  padding: 16px 18px 18px;
  border: 2px solid var(--line-strong);
  border-left: 5px solid var(--moss);
  background: linear-gradient(150deg, rgba(12, 42, 32, .92), rgba(7, 26, 20, .92));
  box-shadow: 4px 4px 0 rgba(3, 8, 7, .82);
  scroll-margin-top: calc(var(--header-h) + 26px);
  transition: border-left-color .2s var(--ease), transform .2s var(--ease);
}

.page-about .timeline__item:hover {
  border-left-color: var(--cyan);
}

.page-about .timeline__year {
  display: inline-block;
  padding: 2px 9px;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .12em;
  color: var(--cyan);
  border: 1px solid rgba(56, 242, 208, .6);
  background: rgba(56, 242, 208, .1);
}

.page-about .timeline__name {
  margin: 11px 0 0;
  font-size: 1.02rem;
  font-weight: 700;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .timeline__desc {
  margin: 8px 0 0;
  font-size: .88rem;
  line-height: 1.7;
  color: rgba(242, 237, 227, .76);
}

/* ---------- 原则 ---------- */
.page-about .principles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .principle {
  border: 2px solid var(--line-strong);
  background: rgba(12, 42, 32, .55);
  transition: border-color .2s var(--ease), background .2s var(--ease);
}

.page-about .principle[open] {
  border-color: rgba(56, 242, 208, .5);
  background: rgba(12, 42, 32, .82);
}

.page-about .principle__sum {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  list-style: none;
  cursor: pointer;
  color: var(--paper);
}

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

.page-about .principle__num {
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .12em;
  color: var(--clay);
  flex: 0 0 auto;
  transition: color .2s var(--ease);
}

.page-about .principle[open] .principle__num {
  color: var(--cyan);
}

.page-about .principle__name {
  flex: 1 1 auto;
  min-width: 0;
  font-size: .98rem;
  font-weight: 700;
}

.page-about .principle__sign {
  position: relative;
  flex: 0 0 auto;
  width: 14px;
  height: 14px;
}

.page-about .principle__sign::before,
.page-about .principle__sign::after {
  content: "";
  position: absolute;
  background: var(--cyan);
  transition: transform .2s var(--ease), opacity .2s var(--ease);
}

.page-about .principle__sign::before {
  left: 0;
  top: 6px;
  width: 14px;
  height: 2px;
}

.page-about .principle__sign::after {
  left: 6px;
  top: 0;
  width: 2px;
  height: 14px;
}

.page-about .principle[open] .principle__sign::after {
  transform: scaleY(0);
  opacity: 0;
}

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

.page-about .principle__text {
  margin: 0;
  font-size: .88rem;
  line-height: 1.72;
  color: rgba(242, 237, 227, .78);
}

.page-about .principle__scene {
  margin: 12px 0 0;
  padding: 10px 12px;
  border-left: 2px solid var(--cyan);
  background: rgba(56, 242, 208, .06);
  font-size: .84rem;
  line-height: 1.68;
  color: rgba(242, 237, 227, .88);
}

.page-about .principle__scene b {
  display: block;
  margin-bottom: 4px;
  font-family: var(--font-mono);
  font-weight: 400;
  font-size: .68rem;
  letter-spacing: .14em;
  color: var(--cyan);
}

/* ---------- 服务版图 ---------- */
.page-about .scenes {
  list-style: none;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin: 0;
  padding: 0;
}

.page-about .scene {
  padding: 18px 18px 20px;
  border: 2px solid var(--line-strong);
  background: linear-gradient(160deg, rgba(79, 111, 82, .18), rgba(7, 26, 20, .62));
}

.page-about .scene__tag {
  display: inline-block;
  padding: 2px 8px;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .14em;
  color: var(--ink);
  background: var(--paper);
}

.page-about .scene__title {
  margin: 12px 0 0;
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .scene__desc {
  margin: 8px 0 0;
  font-size: .86rem;
  line-height: 1.7;
  color: rgba(242, 237, 227, .76);
}

/* ---------- 团队（浅色面板） ---------- */
.page-about .about-paper {
  padding: 22px 18px 20px;
  border: 3px solid var(--black);
  background: var(--paper);
  box-shadow: var(--shadow-hard);
  color: var(--ink);
}

.page-about .about-paper__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
  align-items: start;
}

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

.page-about .about-paper__title {
  margin: 0;
  font-size: 1.18rem;
  font-weight: 800;
  line-height: 1.3;
  color: var(--ink);
}

.page-about .about-paper__text {
  margin: 12px 0 0;
  font-size: .88rem;
  line-height: 1.75;
  color: var(--ink-lift);
}

.page-about .about-paper__figure {
  margin: 0;
}

.page-about .about-paper__facts {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 22px 0 0;
  padding: 0;
  border-top: 2px solid rgba(3, 8, 7, .85);
  background: rgba(3, 8, 7, .14);
}

.page-about .about-paper__facts li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 10px;
  background: var(--paper);
}

.page-about .about-paper__facts .mono {
  font-family: var(--font-mono);
  font-size: 1.08rem;
  line-height: 1;
  letter-spacing: .02em;
  color: var(--clay);
}

.page-about .about-paper__facts em {
  font-style: normal;
  font-size: .74rem;
  letter-spacing: .04em;
  color: var(--moss);
}

/* ---------- 合作生态 ---------- */
.page-about .eco-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .eco-card {
  padding: 16px 16px 18px;
  border-top: 3px solid var(--cyan);
  border-right: 2px solid var(--line-strong);
  border-bottom: 2px solid var(--line-strong);
  border-left: 2px solid var(--line-strong);
  background: rgba(7, 26, 20, .52);
}

.page-about .eco-card__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.6rem;
  line-height: 1;
  letter-spacing: .03em;
  color: var(--cyan);
}

.page-about .eco-card__name {
  margin: 10px 0 0;
  font-size: .95rem;
  font-weight: 700;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .eco-card__desc {
  margin: 8px 0 0;
  font-size: .85rem;
  line-height: 1.7;
  color: rgba(242, 237, 227, .74);
}

/* ---------- 品牌问答 ---------- */
.page-about .about-qa {
  display: grid;
  gap: 0;
}

.page-about .qa {
  padding: 20px 0;
  border-top: 1px solid var(--line);
}

.page-about .qa:first-child {
  border-top: 2px solid var(--line-strong);
  padding-top: 18px;
}

.page-about .qa__q {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin: 0;
  font-size: clamp(1rem, 3vw, 1.14rem);
  font-weight: 700;
  line-height: 1.45;
  color: var(--paper);
}

.page-about .qa__q span {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .1em;
  color: var(--clay);
}

.page-about .qa__a {
  margin: 10px 0 0 34px;
  font-size: .88rem;
  line-height: 1.78;
  color: rgba(242, 237, 227, .78);
}

/* ---------- 继续了解 ---------- */
.page-about .about-next {
  margin-bottom: 54px;
  padding: 22px 18px;
  border: 2px solid var(--line-strong);
  background: linear-gradient(135deg, rgba(12, 42, 32, .92), rgba(7, 26, 20, .92));
}

.page-about .about-next__title {
  margin: 0 0 16px;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--paper);
}

.page-about .about-next__list {
  list-style: none;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  margin: 0;
  padding: 0;
}

.page-about .about-next__link {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 13px 14px 13px 16px;
  border-left: 2px solid var(--moss);
  text-decoration: none;
  transition: border-color .18s var(--ease), background .18s var(--ease);
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  border-left-color: var(--flare);
  background: rgba(255, 77, 46, .08);
}

.page-about .about-next__label {
  font-size: .95rem;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-next__desc {
  font-size: .8rem;
  line-height: 1.6;
  color: var(--stone);
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .scenes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .about-next__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .qa__a {
    margin-left: 38px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 30px 0 52px;
  }

  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
    gap: 44px;
  }

  .page-about .principles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .about-paper {
    padding: 28px 26px 26px;
  }

  .page-about .about-paper__grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
    gap: 28px;
  }

  .page-about .about-next {
    padding: 26px 24px;
  }

  .page-about .qa {
    padding: 24px 0;
  }
}

@media (min-width: 1000px) {
  .page-about .about-rail {
    display: block;
  }

  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
    padding-top: 48px;
  }

  .page-about .about-sec {
    margin-bottom: 78px;
  }

  .page-about .about-sec__head {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    column-gap: 18px;
    align-items: start;
  }

  .page-about .about-sec__num {
    grid-row: 1 / span 2;
    margin: 6px 0 0;
  }

  .page-about .about-sec__title {
    grid-column: 2;
  }

  .page-about .about-sec__lede {
    grid-column: 2;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about {
    scroll-behavior: auto;
  }

  .page-about .timeline__item,
  .page-about .principle,
  .page-about .principle__sign::before,
  .page-about .principle__sign::after,
  .page-about .about-rail__link,
  .page-about .about-scale__item,
  .page-about .about-next__link {
    transition: none;
  }
}