.page-about {
  --about-rail: 210px;
  --about-gap: clamp(20px, 3vw, 32px);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding: clamp(40px, 7vw, 88px) 0 clamp(40px, 6vw, 80px);
  overflow: hidden;
  isolation: isolate;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -12% -18% auto auto;
  width: min(78vw, 760px);
  height: 118%;
  background:
    linear-gradient(126deg, transparent 58%, rgba(53, 240, 140, 0.06) 58.1%, rgba(53, 240, 140, 0.06) 70%, transparent 70.1%),
    linear-gradient(126deg, transparent 74%, rgba(30, 40, 57, 0.85) 74.1%, rgba(30, 40, 57, 0.85) 100%);
  pointer-events: none;
  z-index: -1;
}

.page-about .about-hero__inner {
  display: grid;
  gap: var(--about-gap);
}

.page-about .about-hero__title {
  font-size: clamp(34px, 6.4vw, 78px);
  font-weight: 250;
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0;
  max-width: 20ch;
}

.page-about .about-hero__lede {
  display: grid;
  gap: 16px;
  max-width: 62ch;
}

.page-about .about-hero__lede p {
  margin: 0;
}

.page-about .about-hero__meta {
  margin: 8px 0 0;
  display: grid;
  gap: 1px;
  background: var(--slate-700);
  border: 1px solid var(--slate-700);
  grid-template-columns: 1fr;
}

.page-about .about-hero__stat {
  background: var(--ink-900);
  padding: 18px 20px;
  display: grid;
  gap: 6px;
}

.page-about .about-hero__stat dt {
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--fog-500);
}

.page-about .about-hero__stat dd {
  margin: 0;
  font-size: 15px;
  color: var(--fog-200);
}

.page-about .about-hero__num {
  color: var(--signal-green);
  font-size: 22px;
  font-weight: 700;
  margin-right: 4px;
}

/* ---------- 研究板 ---------- */

.page-about .about-research .prose {
  margin-bottom: clamp(28px, 4vw, 44px);
}

.page-about .research-board {
  display: grid;
  gap: 1px;
  background: var(--slate-700);
  border: 1px solid var(--slate-700);
}

.page-about .research-card {
  background: var(--ink-800);
  padding: clamp(22px, 3vw, 32px);
  display: grid;
  gap: 14px;
  align-content: start;
}

.page-about .research-card__tag {
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--signal-green);
  margin: 0;
  text-transform: uppercase;
}

.page-about .research-card--lead {
  background: var(--ink-900);
}

.page-about .research-card__claim {
  margin: 0;
  font-size: clamp(20px, 3vw, 30px);
  font-weight: 300;
  line-height: 1.45;
  letter-spacing: -0.01em;
  color: var(--paper-050);
  max-width: 34ch;
}

.page-about .research-card__note {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--fog-500);
  max-width: 48ch;
}

.page-about .research-card__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .research-card__list li {
  font-size: 15px;
  line-height: 1.75;
  color: var(--fog-200);
  padding-left: 16px;
  border-left: 1px solid var(--slate-600);
}

.page-about .research-card__key {
  display: block;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--signal-green);
  margin-bottom: 4px;
}

.page-about .research-card__hint {
  margin: 0;
  font-size: 13px;
  color: var(--fog-500);
}

.page-about .research-card__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .research-card__links li {
  font-size: 15px;
  line-height: 1.7;
  color: var(--fog-200);
}

.page-about .research-card__links a {
  color: var(--signal-green);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease);
}

.page-about .research-card__links a:hover,
.page-about .research-card__links a:focus-visible {
  border-bottom-color: var(--signal-green);
}

/* 术语折叠 */

.page-about .glossary {
  display: grid;
  gap: 1px;
  background: var(--slate-700);
  border-top: 1px solid var(--slate-700);
  border-bottom: 1px solid var(--slate-700);
}

.page-about .glossary__item {
  background: var(--ink-800);
}

.page-about .glossary__summary {
  list-style: none;
  cursor: pointer;
  min-height: 44px;
  display: flex;
  align-items: center;
  padding: 10px 2px;
  font-size: 14px;
  color: var(--fog-200);
  position: relative;
  padding-right: 28px;
}

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

.page-about .glossary__summary::after {
  content: "+";
  position: absolute;
  right: 4px;
  font-family: var(--font-mono);
  color: var(--signal-green);
  font-size: 16px;
  transition: transform var(--dur) var(--ease);
}

.page-about .glossary__item[open] .glossary__summary::after {
  content: "−";
}

.page-about .glossary__summary:focus-visible {
  outline: 2px solid var(--signal-green);
  outline-offset: 2px;
}

.page-about .glossary__body {
  margin: 0 0 14px;
  font-size: 13px;
  line-height: 1.75;
  color: var(--fog-500);
  max-width: 42ch;
}

/* 数据链路图 */

.page-about .dataflow {
  margin: clamp(28px, 4vw, 44px) 0 0;
  padding: clamp(18px, 3vw, 28px);
  border: 1px solid var(--slate-600);
  background: rgba(18, 26, 40, 0.5);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.page-about .dataflow svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .dataflow__caption {
  margin: 12px 0 0;
  font-size: 12px;
  line-height: 1.7;
  color: var(--fog-500);
}

/* ---------- 团队 ---------- */

.page-about .about-team .prose {
  margin-bottom: clamp(28px, 4vw, 44px);
}

.page-about .team-grid {
  align-items: start;
}

.page-about .team-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--slate-700);
  border: 1px solid var(--slate-700);
}

.page-about .team-item {
  background: var(--ink-900);
  padding: 22px 22px 24px;
  display: grid;
  gap: 8px;
  grid-template-columns: auto 1fr;
  grid-template-areas:
    "idx name"
    ".   body";
  column-gap: 14px;
}

.page-about .team-item__idx {
  grid-area: idx;
  font-size: 12px;
  color: var(--signal-green);
  padding-top: 4px;
}

.page-about .team-item__name {
  grid-area: name;
  margin: 0;
  font-size: 17px;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--paper-050);
}

.page-about .team-item p {
  grid-area: body;
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--fog-200);
}

.page-about .team-grid__media {
  margin: 0;
}

/* ---------- 版本时间线 ---------- */

.page-about .about-versions .prose {
  margin-bottom: clamp(24px, 3vw, 36px);
}

.page-about .versions-banner {
  margin: 0 0 clamp(28px, 4vw, 48px);
}

.page-about .version-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 4vw, 48px);
}

.page-about .version-rail {
  border-top: 1px solid var(--slate-700);
  padding-top: 14px;
}

.page-about .version-rail__title {
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--fog-500);
  margin: 0 0 12px;
}

.page-about .version-rail__list {
  list-style: none;
  margin: 0;
  padding: 0 0 8px;
  display: flex;
  gap: 10px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .version-rail__link {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 0 0 auto;
  min-width: 104px;
  min-height: 44px;
  padding: 10px 12px;
  text-decoration: none;
  border-left: 2px solid var(--slate-600);
  color: var(--fog-500);
  font-size: 13px;
  line-height: 1.4;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .version-rail__link .mono {
  font-size: 12px;
  letter-spacing: 0.06em;
}

.page-about .version-rail__link:hover,
.page-about .version-rail__link:focus-visible {
  color: var(--fog-200);
  border-left-color: var(--signal-green);
  background: rgba(53, 240, 140, 0.05);
}

.page-about .version-rail__link:focus-visible {
  outline: 2px solid var(--signal-green);
  outline-offset: 2px;
}

.page-about .version-list {
  display: grid;
  gap: 0;
}

.page-about .version-block {
  padding: clamp(22px, 3vw, 32px) 0;
  border-top: 1px solid var(--slate-700);
  scroll-margin-top: 120px;
}

.page-about .version-block:first-child {
  border-top: none;
  padding-top: 0;
}

.page-about .version-block__no {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--signal-green);
}

.page-about .version-block h3 {
  margin: 0 0 10px;
  font-size: clamp(19px, 2.6vw, 24px);
  font-weight: 400;
  line-height: 1.4;
  color: var(--paper-050);
}

.page-about .version-block p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--fog-200);
  max-width: 46ch;
}

.page-about .version-block:target {
  border-top-color: var(--signal-green);
}

.page-about .version-block:target h3 {
  color: var(--signal-green);
}

/* ---------- 覆盖规模（反色实色锚点） ---------- */

.page-about .about-scale {
  padding-left: 0;
  padding-right: 0;
}

.page-about .about-scale > .container {
  margin-bottom: clamp(28px, 4vw, 44px);
}

.page-about .scale-panel {
  background: var(--paper-050);
  color: var(--ink-950);
  padding: clamp(28px, 5vw, 56px);
  display: grid;
  gap: 20px;
}

.page-about .scale-panel__title {
  margin: 0;
  font-size: clamp(22px, 3.4vw, 36px);
  font-weight: 300;
  letter-spacing: -0.01em;
  line-height: 1.25;
  color: var(--ink-950);
  max-width: 24ch;
}

.page-about .scale-panel__lede {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: #3B465B;
  max-width: 56ch;
}

.page-about .scale-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: rgba(4, 6, 11, 0.14);
  border-top: 1px solid rgba(4, 6, 11, 0.14);
  border-bottom: 1px solid rgba(4, 6, 11, 0.14);
}

.page-about .scale-item {
  background: var(--paper-050);
  padding: 16px 4px;
  display: grid;
  gap: 4px;
}

.page-about .scale-item__value {
  font-size: clamp(26px, 4vw, 38px);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink-950);
  line-height: 1;
}

.page-about .scale-item__label {
  font-size: 14px;
  font-weight: 500;
  color: var(--ink-950);
}

.page-about .scale-item__note {
  font-size: 12px;
  line-height: 1.6;
  color: #4C5769;
}

.page-about .scale-media {
  display: block;
  margin: 0;
  width: 100%;
}

.page-about .scale-media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 21 / 9;
  object-fit: cover;
}

.page-about .scale-media__caption {
  max-width: var(--shell-max);
  margin: 12px auto 0;
  padding: 0 var(--gutter);
  font-size: 12px;
  line-height: 1.7;
  color: var(--fog-500);
}

/* ---------- 边界与联系 ---------- */

.page-about .boundary-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 3.5vw, 40px);
  align-items: start;
}

.page-about .boundary-copy {
  display: grid;
  gap: 16px;
}

.page-about .boundary-copy p {
  margin: 0;
}

.page-about .boundary-contact {
  padding: clamp(22px, 3vw, 30px);
  display: grid;
  gap: 14px;
}

.page-about .boundary-contact__title {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--signal-green);
}

.page-about .boundary-contact .contact-list {
  margin: 0;
  display: grid;
  gap: 14px;
}

.page-about .boundary-contact__note {
  margin: 0;
  font-size: 12px;
  line-height: 1.7;
  color: var(--fog-500);
  border-top: 1px solid var(--slate-700);
  padding-top: 12px;
}

/* ---------- 图片与媒体 ---------- */

.page-about .media-frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--slate-700);
  background: var(--ink-800);
}

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

.page-about .media-frame__caption {
  margin: 0;
  padding: 10px 14px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--fog-500);
  border-top: 1px solid var(--slate-700);
  background: var(--ink-900);
}

.page-about .ratio-4x3 img {
  aspect-ratio: 4 / 3;
}

.page-about .ratio-21x9 img {
  aspect-ratio: 21 / 9;
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-hero__meta {
    grid-template-columns: repeat(3, 1fr);
  }

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

@media (min-width: 900px) {
  .page-about .research-board {
    grid-template-columns: repeat(12, 1fr);
  }

  .page-about .research-card--lead {
    grid-column: 1 / -1;
    padding: clamp(32px, 4vw, 48px);
  }

  .page-about .research-card--boundary {
    grid-column: span 7;
  }

  .page-about .research-card--glossary {
    grid-column: span 5;
  }

  .page-about .research-card--further {
    grid-column: 1 / -1;
  }

  .page-about .version-layout {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
  }

  .page-about .version-rail {
    position: sticky;
    top: 116px;
    align-self: start;
    border-top: none;
    padding-top: 0;
    border-left: 1px solid var(--slate-700);
    padding-left: 18px;
  }

  .page-about .version-rail__list {
    flex-direction: column;
    gap: 4px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .version-rail__link {
    min-width: 0;
    width: 100%;
  }

  .page-about .boundary-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }

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

@media (min-width: 1200px) {
  .page-about .scale-item {
    padding: 20px 8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .glossary__summary::after,
  .page-about .version-rail__link {
    transition: none;
  }
}