.page-about {
  --about-line: rgba(30, 76, 64, .55);
  --about-line-soft: rgba(30, 76, 64, .32);
  position: relative;
  counter-reset: chapter;
  overflow-x: clip;
  color: var(--white);
  padding-bottom: clamp(3rem, 8vw, 6rem);
}

.page-about::before {
  content: "";
  position: absolute;
  inset: -6rem -20% auto -20%;
  height: 62vh;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(46% 58% at 16% 14%, rgba(47, 224, 200, .15), transparent 70%),
    radial-gradient(38% 52% at 84% 6%, rgba(255, 90, 31, .11), transparent 74%);
  animation: about-drift 24s var(--ease) infinite alternate;
}

@keyframes about-drift {
  from { transform: translate3d(0, 0, 0) scale(1); }
  to   { transform: translate3d(0, 2.5%, 0) scale(1.04); }
}

.page-about .wrap {
  position: relative;
  z-index: 1;
}

.page-about .breadcrumb {
  padding-top: clamp(1rem, 3vw, 1.8rem);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding-top: clamp(1.2rem, 3vw, 2rem);
  padding-bottom: clamp(1.6rem, 4vw, 2.6rem);
}

.page-about .about-hero-inner {
  display: grid;
  gap: clamp(1.6rem, 4vw, 3rem);
}

.page-about .about-hero-copy .display-title {
  font-size: clamp(2.1rem, 6vw, 4.2rem);
  line-height: 1.08;
  letter-spacing: -0.015em;
  margin: .7rem 0 0;
}

.page-about .about-hero-copy .lede {
  margin-top: 1.3rem;
  max-width: 34em;
  color: var(--white);
  opacity: .88;
}

.page-about .about-hero-figure {
  margin: 0;
  border: 1px solid var(--about-line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 2rem), 0 100%);
  overflow: hidden;
  background: linear-gradient(150deg, rgba(18, 53, 44, .92), rgba(4, 18, 14, .7));
}

.page-about .about-hero-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  filter: saturate(.92);
}

.page-about .about-hero-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: clamp(1.6rem, 4vw, 2.8rem);
  border-top: 1px solid var(--about-line);
  border-bottom: 1px solid var(--about-line-soft);
}

.page-about .about-hero-stat {
  padding: 1rem .5rem 1.1rem 0;
  border-right: 1px solid var(--about-line-soft);
}

.page-about .about-hero-stat:last-child {
  border-right: 0;
  padding-left: .9rem;
}

.page-about .about-hero-stat:not(:first-child) {
  padding-left: .9rem;
}

.page-about .about-hero-stat-value {
  display: block;
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 400;
  letter-spacing: .01em;
  color: var(--cyan);
  line-height: 1.1;
}

.page-about .about-hero-stat-label {
  display: block;
  margin-top: .35rem;
  font-size: .74rem;
  font-weight: 300;
  letter-spacing: .06em;
  color: var(--muted);
}

/* ---------- 章节骨架 ---------- */

.page-about .about-chapter {
  counter-increment: chapter;
  padding-block: clamp(2.4rem, 6.5vw, 5rem);
  border-top: 1px solid var(--about-line-soft);
}

.page-about .about-chapter-grid {
  display: grid;
  gap: 1.1rem;
}

.page-about .about-chapter-main {
  min-width: 0;
}

.page-about .about-chapter-main .section-title {
  max-width: 20em;
  margin: 0 0 1.1rem;
}

.page-about .about-chapter-lede {
  max-width: 34em;
  color: var(--white);
  opacity: .86;
}

.page-about .about-chapter-lede--plain {
  margin: 0 0 1.6rem;
  font-size: .95rem;
  line-height: 1.75;
}

.page-about .about-chapter-aside {
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .22em;
  color: var(--muted);
}

.page-about .about-chapter-aside::before,
.page-about .about-chapter-num::before {
  content: counter(chapter, decimal-leading-zero);
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.3rem, 3.4vw, 1.9rem);
  font-weight: 300;
  letter-spacing: .06em;
  line-height: 1;
  color: var(--cyan);
  opacity: .9;
  margin-bottom: .55rem;
}

.page-about .about-chapter-label {
  display: block;
  text-transform: uppercase;
}

/* ---------- 场景列表 ---------- */

.page-about .about-scene-list {
  list-style: none;
  margin: 1.9rem 0 0;
  padding: 0;
  border-top: 1px solid var(--about-line-soft);
}

.page-about .about-scene {
  display: grid;
  gap: .35rem;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--about-line-soft);
}

.page-about .about-scene-title {
  margin: 0;
  font-size: .95rem;
  font-weight: 500;
  letter-spacing: .01em;
  color: var(--white);
}

.page-about .about-scene p {
  margin: 0;
  font-size: .88rem;
  line-height: 1.82;
  color: var(--muted);
}

/* ---------- 版本轴线 ---------- */

.page-about .about-chapter--versions {
  background:
    linear-gradient(180deg, rgba(8, 31, 25, .55), rgba(4, 18, 14, 0) 42%),
    radial-gradient(70% 40% at 88% 0%, rgba(47, 224, 200, .1), transparent 72%);
}

.page-about .about-version-grid {
  display: grid;
  gap: clamp(1.8rem, 4.5vw, 3rem);
}

.page-about .about-version-lede {
  max-width: 34em;
  margin: 0 0 1.8rem;
  font-size: .92rem;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-timeline {
  position: relative;
  padding-left: 1.5rem;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 1.1rem;
  bottom: 1.1rem;
  width: 1px;
  background: linear-gradient(180deg, transparent, var(--cyan) 8%, var(--edge) 45%, var(--edge) 88%, transparent);
  opacity: .8;
}

.page-about .about-node-item {
  border-bottom: 1px solid var(--about-line-soft);
}

.page-about .about-node-item:last-child {
  border-bottom: 0;
}

.page-about .about-timeline .fold-head {
  position: relative;
  display: grid;
  grid-template-columns: 2.6rem minmax(0, 1fr) 1.1rem;
  align-items: center;
  gap: .85rem;
  width: 100%;
  padding: .95rem 0;
  background: none;
  border: 0;
  color: inherit;
  text-align: left;
  font: inherit;
  cursor: pointer;
  transition: color var(--dur) var(--ease);
}

.page-about .about-node-dot {
  position: absolute;
  left: -1.5rem;
  top: 50%;
  width: 9px;
  height: 9px;
  margin-top: -4.5px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--cyan);
  transition: background var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .about-node[aria-expanded="true"] .about-node-dot {
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(47, 224, 200, .14);
}

.page-about .about-node-code {
  font-size: .74rem;
  letter-spacing: .14em;
  color: var(--cyan);
  opacity: .85;
}

.page-about .about-node-title {
  font-size: .95rem;
  font-weight: 400;
  line-height: 1.5;
  color: var(--white);
  transition: color var(--dur) var(--ease);
}

.page-about .about-node:hover .about-node-title,
.page-about .about-node:focus-visible .about-node-title {
  color: var(--mist);
}

.page-about .about-timeline .fold-sign {
  color: var(--flame);
  font-size: 1rem;
  line-height: 1;
  justify-self: end;
}

.page-about .about-timeline .fold-body {
  padding: 0 0 1.3rem 0;
}

.page-about .about-timeline .fold-body p {
  margin: 0 0 0 3.45rem;
  max-width: 32em;
  font-size: .88rem;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-version-side {
  min-width: 0;
}

.page-about .about-archive-figure {
  margin: 0;
  border: 1px solid var(--about-line);
  overflow: hidden;
  clip-path: polygon(0 0, calc(100% - 1.6rem) 0, 100% 1.6rem, 100% 100%, 0 100%);
  background: linear-gradient(200deg, rgba(18, 53, 44, .9), rgba(4, 18, 14, .65));
}

.page-about .about-archive-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 5 / 6;
  object-fit: cover;
  opacity: .82;
}

/* ---------- 数据能力 ---------- */

.page-about .about-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 1.9rem 0 0;
  background: var(--about-line-soft);
  border: 1px solid var(--about-line);
}

.page-about .about-metric {
  background: linear-gradient(160deg, rgba(18, 53, 44, .72), rgba(8, 31, 25, .88));
  padding: 1.05rem 1rem 1.15rem;
}

.page-about .about-metric-value {
  display: block;
  font-size: clamp(1.35rem, 3.6vw, 1.8rem);
  font-weight: 400;
  letter-spacing: .01em;
  line-height: 1.1;
  color: var(--cyan);
}

.page-about .about-metric-label {
  display: block;
  margin-top: .4rem;
  font-size: .72rem;
  font-weight: 300;
  letter-spacing: .05em;
  color: var(--muted);
}

.page-about .about-data-figure {
  margin: 1.6rem 0 0;
  border: 1px solid var(--about-line);
  overflow: hidden;
  background: linear-gradient(120deg, rgba(8, 31, 25, .9), rgba(4, 18, 14, .7));
}

.page-about .about-data-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

.page-about .about-data-figure .figure-cap {
  padding: .7rem 1rem .85rem;
  font-size: .72rem;
  font-weight: 300;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 团队分工 ---------- */

.page-about .about-team {
  display: grid;
  margin-top: 1.6rem;
  border-top: 1px solid var(--about-line-soft);
}

.page-about .about-team-row {
  display: grid;
  gap: .45rem;
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--about-line-soft);
}

.page-about .about-team-name {
  margin: 0;
  justify-self: start;
  font-family: var(--font-mono);
  font-size: .74rem;
  font-weight: 400;
  letter-spacing: .16em;
  color: var(--cyan);
  padding: .28rem .6rem;
  border: 1px solid var(--edge);
  background: linear-gradient(135deg, rgba(47, 224, 200, .14), rgba(47, 224, 200, 0));
}

.page-about .about-team-text {
  margin: 0;
  font-size: .88rem;
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 安全与适配 ---------- */

.page-about .about-security {
  display: grid;
  gap: 1px;
  margin-top: 1.9rem;
  background: var(--about-line-soft);
  border: 1px solid var(--about-line);
}

.page-about .about-security-item {
  background: rgba(8, 31, 25, .72);
  padding: 1.15rem 1.05rem 1.3rem;
}

.page-about .about-security-index {
  display: block;
  font-size: .72rem;
  letter-spacing: .2em;
  color: var(--flame);
}

.page-about .about-security-title {
  margin: .6rem 0 .5rem;
  font-size: .95rem;
  font-weight: 500;
  color: var(--white);
}

.page-about .about-security-item p {
  margin: 0;
  font-size: .86rem;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 延伸入口 ---------- */

.page-about .about-next {
  padding-top: clamp(2.2rem, 6vw, 4rem);
  border-top: 1px solid var(--about-line-soft);
}

.page-about .about-next .section-title {
  margin-bottom: .9rem;
}

.page-about .about-next-lede {
  max-width: 32em;
  margin: 0;
  font-size: .9rem;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-next-track {
  display: flex;
  gap: .9rem;
  margin-top: 1.6rem;
  padding-bottom: .8rem;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-about .about-next-card {
  flex: 0 0 min(76vw, 16rem);
  scroll-snap-align: start;
  display: grid;
  align-content: start;
  gap: .55rem;
  padding: 1.15rem 1.05rem 1.35rem;
  border: 1px solid var(--about-line);
  background: linear-gradient(165deg, rgba(18, 53, 44, .8), rgba(4, 18, 14, .5));
  text-decoration: none;
  color: inherit;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-next-card:hover,
.page-about .about-next-card:focus-visible {
  border-color: rgba(47, 224, 200, .6);
  transform: translateY(-3px);
  background: linear-gradient(165deg, rgba(18, 53, 44, .95), rgba(4, 18, 14, .6));
}

.page-about .about-next-index {
  font-size: .7rem;
  letter-spacing: .2em;
  color: var(--flame);
}

.page-about .about-next-title {
  font-size: 1.02rem;
  font-weight: 500;
  color: var(--white);
}

.page-about .about-next-text {
  font-size: .82rem;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 断点 ---------- */

@media (min-width: 700px) {
  .page-about .about-scene {
    grid-template-columns: 14rem minmax(0, 1fr);
    gap: 1.6rem;
    align-items: baseline;
  }

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

  .page-about .about-team-row {
    grid-template-columns: 9.5rem minmax(0, 1fr);
    gap: 1.8rem;
    align-items: start;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
    align-items: end;
    gap: clamp(2rem, 4vw, 3.6rem);
  }

  .page-about .about-chapter-grid {
    grid-template-columns: minmax(0, 1fr) 7.5rem;
    gap: clamp(2rem, 4vw, 3.4rem);
    align-items: start;
  }

  .page-about .about-chapter-aside {
    text-align: right;
  }

  .page-about .about-chapter-aside::before {
    font-size: 2.1rem;
  }

  .page-about .about-version-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 16.5rem);
    align-items: start;
    gap: clamp(2rem, 4vw, 3.4rem);
  }

  .page-about .about-version-side {
    position: sticky;
    top: 6.5rem;
  }
}

@media (min-width: 1180px) {
  .page-about .about-version-grid {
    grid-template-columns: minmax(0, 1fr) 19rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about::before {
    animation: none;
  }

  .page-about .about-next-card,
  .page-about .about-node-dot,
  .page-about .about-node-title {
    transition: none;
  }

  .page-about .about-next-card:hover {
    transform: none;
  }
}