.page-about {
  --about-gold-line: rgba(201, 162, 39, .38);
  --about-hair: rgba(199, 203, 214, .18);
  background: var(--indigo-950);
  color: var(--ink-soft);
  overflow-x: clip;
}

.page-about .breadcrumb {
  padding: 18px 0 0;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 32px 0 46px;
  background:
    radial-gradient(120% 90% at 88% -10%, rgba(201, 162, 39, .14), transparent 62%),
    linear-gradient(180deg, var(--indigo-900) 0%, var(--indigo-950) 100%);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(199, 203, 214, .055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(199, 203, 214, .055) 1px, transparent 1px);
  background-size: 68px 68px;
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -8%;
  bottom: -30%;
  width: 62%;
  height: 70%;
  border: 1px solid rgba(231, 205, 122, .18);
  border-radius: 50%;
  transform: rotate(-14deg);
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 32px;
}

.page-about .about-hero__main {
  max-width: 720px;
}

.page-about .about-hero__title {
  margin: 14px 0 18px;
  font-family: var(--font-head);
  font-size: clamp(34px, 7.4vw, 64px);
  font-weight: 900;
  line-height: 1.12;
  letter-spacing: -.01em;
  color: var(--gray-050);
  text-wrap: balance;
}

.page-about .about-hero__lead {
  max-width: 44ch;
  color: var(--ink-soft);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero__aside {
  position: relative;
  padding: 24px 22px 26px 24px;
  background: linear-gradient(155deg, var(--indigo-700), var(--indigo-900));
  border-left: 2px solid var(--gold-500);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%);
}

.page-about .about-hero__mark {
  margin: 0 0 18px;
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--gold-300);
}

.page-about .about-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-facts__item {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-facts__item:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-facts__num {
  flex: none;
  min-width: 5.6ch;
  font-size: 22px;
  font-weight: 600;
  color: var(--gold-500);
}

.page-about .about-facts__label {
  font-size: 14px;
  color: var(--gray-300);
}

.page-about .about-hero__tag {
  display: none;
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%) rotate(-90deg);
  transform-origin: right center;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .28em;
  color: var(--gold-300);
  white-space: nowrap;
}

/* ---------- 通用标题 ---------- */
.page-about .about-h2 {
  margin: 12px 0 18px;
  font-family: var(--font-head);
  font-size: clamp(24px, 4.6vw, 40px);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: -.01em;
  color: var(--gray-050);
}

.page-about .about-h2--dark {
  color: var(--indigo-900);
}

/* ---------- 版本时间带 ---------- */
.page-about .about-line {
  background: linear-gradient(180deg, var(--indigo-950), var(--indigo-900));
}

.page-about .about-line__head {
  max-width: 62ch;
  margin-bottom: 28px;
}

.page-about .about-line__figure {
  margin: 0 0 34px;
}

.page-about .about-track {
  list-style: none;
  margin: 0;
  padding: 0 0 14px;
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(190px, 78%);
  gap: 16px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-track__node {
  position: relative;
  scroll-snap-align: start;
  padding: 18px 16px 20px;
  background: var(--indigo-700);
  border-top: 2px solid var(--about-gold-line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%);
}

.page-about .about-track__node::after {
  content: "";
  position: absolute;
  right: -16px;
  top: 22px;
  width: 16px;
  height: 1px;
  background: linear-gradient(90deg, var(--gold-500), transparent);
  transform: rotate(-24deg);
  transform-origin: left center;
}

.page-about .about-track__node:last-child::after {
  display: none;
}

.page-about .about-track__node.is-current {
  background: linear-gradient(150deg, rgba(201, 162, 39, .24), var(--indigo-700));
  border-top-color: var(--gold-500);
}

.page-about .about-track__ver {
  display: block;
  font-size: 18px;
  font-weight: 600;
  color: var(--gold-500);
}

.page-about .about-track__name {
  display: block;
  margin-top: 8px;
  font-family: var(--font-head);
  font-size: 16px;
  font-weight: 700;
  color: var(--gray-050);
}

.page-about .about-track__desc {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--gray-300);
}

/* ---------- 阶段面板 ---------- */
.page-about .about-stages__grid {
  display: grid;
  gap: 24px;
}

.page-about .about-index {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding-bottom: 4px;
}

.page-about .about-index .side-index__item {
  flex: none;
  padding: 6px 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--gray-300);
  border: 1px solid var(--about-hair);
  text-decoration: none;
  white-space: nowrap;
}

.page-about .about-index .side-index__item[aria-current="true"] {
  color: var(--indigo-950);
  background: var(--gold-500);
  border-color: var(--gold-500);
}

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

.page-about .about-stage {
  margin-top: 14px;
  background: var(--indigo-700);
  border-left: 2px solid rgba(231, 205, 122, .28);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%);
  transition: border-color .2s ease;
}

.page-about .about-stage[open] {
  border-left-color: var(--gold-500);
}

.page-about .about-stage__sum {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 18px 20px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-stage__num {
  flex: none;
  font-size: 13px;
  color: var(--gold-500);
}

.page-about .about-stage__title {
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 700;
  color: var(--gray-050);
}

.page-about .about-stage__body {
  padding: 0 20px 20px 20px;
}

.page-about .about-stage__body p {
  margin: 0;
  max-width: 46ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-soft);
}

/* ---------- 团队与服务 ---------- */
.page-about .about-team {
  background: linear-gradient(180deg, var(--indigo-900), var(--indigo-950));
}

.page-about .about-team__grid {
  align-items: start;
}

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

.page-about .about-team__stats {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-hair);
}

.page-about .about-stat {
  padding: 16px 14px;
  background: var(--indigo-900);
}

.page-about .about-stat__num {
  display: block;
  font-size: 26px;
  font-weight: 600;
  color: var(--gold-500);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--gray-300);
}

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

/* ---------- 浅色结构区 ---------- */
.page-about .about-system {
  background: var(--gray-050);
  color: var(--graphite-700);
  padding: 46px 0 52px;
  border-top: 1px solid var(--about-hair);
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-system__grid {
  display: grid;
  gap: 26px;
}

.page-about .about-system__lead,
.page-about .about-system__note {
  max-width: 52ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--graphite-700);
}

.page-about .about-system__note {
  margin: 0;
  padding-left: 16px;
  border-left: 3px solid var(--gold-500);
  font-size: 14px;
  color: var(--graphite-700);
}

.page-about .about-metrics {
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.page-about .about-metric {
  padding: 16px 14px;
  background: #fff;
  border-top: 2px solid var(--indigo-700);
  clip-path: polygon(var(--cut) 0, 100% 0, 100% 100%, 0 100%, 0 var(--cut));
}

.page-about .about-metric__label {
  font-size: 13px;
  color: var(--graphite-700);
}

.page-about .about-metric__value {
  margin: 6px 0 0;
  font-size: 30px;
  font-weight: 600;
  color: var(--indigo-700);
}

/* ---------- 原则 ---------- */
.page-about .about-principles__grid {
  margin-top: 26px;
}

.page-about .about-principle {
  position: relative;
  padding: 22px 20px 24px;
  background: linear-gradient(160deg, var(--indigo-700), var(--indigo-900));
  border-left: 2px solid rgba(231, 205, 122, .3);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%);
  transition: border-color .2s ease, transform .24s ease;
}

.page-about .about-principle:hover {
  border-left-color: var(--gold-500);
}

.page-about .about-principle__num {
  display: block;
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--gold-300);
}

.page-about .about-principle__title {
  margin: 12px 0 10px;
  font-family: var(--font-head);
  font-size: 18px;
  font-weight: 800;
  color: var(--gray-050);
}

.page-about .about-principle__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--ink-soft);
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  position: relative;
  overflow: hidden;
  background: var(--indigo-950);
  border-top: 1px solid var(--about-gold-line);
}

.page-about .about-cta__figure {
  position: absolute;
  inset: 0;
  margin: 0;
  opacity: .32;
}

.page-about .about-cta__figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-about .about-cta__inner {
  position: relative;
  z-index: 1;
  padding: 52px 0 58px;
}

.page-about .about-cta__title {
  margin: 0 0 14px;
  max-width: 24ch;
  font-family: var(--font-head);
  font-size: clamp(24px, 4.6vw, 40px);
  font-weight: 800;
  line-height: 1.22;
  color: var(--gray-050);
}

.page-about .about-cta__text {
  max-width: 46ch;
  margin: 0 0 24px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink-soft);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .about-hero {
    padding: 48px 0 64px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(260px, 1fr);
    gap: 44px;
    align-items: center;
  }

  .page-about .about-hero__tag {
    display: block;
  }

  .page-about .about-track {
    grid-auto-flow: row;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    grid-auto-columns: auto;
    overflow-x: visible;
    padding-bottom: 0;
  }

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

  .page-about .about-system__grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-system__head {
    grid-column: 1;
  }

  .page-about .about-metrics {
    grid-column: 2;
    grid-row: 1 / span 2;
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-system__note {
    grid-column: 1;
  }

  .page-about .about-cta__inner {
    padding: 68px 0 74px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-stages__grid {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 36px;
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 24px);
    flex-direction: column;
    gap: 8px;
    overflow: visible;
  }

  .page-about .about-index .side-index__item {
    text-align: left;
    border: 0;
    border-left: 1px solid var(--about-hair);
    padding: 6px 10px;
  }

  .page-about .about-index .side-index__item[aria-current="true"] {
    background: transparent;
    color: var(--gold-500);
    border-left-color: var(--gold-500);
  }
}

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