.page-about {
  --about-rail-w: 220px;
  display: block;
  padding-bottom: clamp(72px, 10vh, 140px);
}

.page-about .nx-crumbs {
  margin-top: clamp(24px, 4vh, 48px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: clamp(32px, 6vh, 72px) 0 clamp(40px, 7vh, 88px);
  border-bottom: var(--line);
}

.page-about .about-hero .nx-h1 {
  max-width: 18ch;
  margin: 12px 0 0;
}

.page-about .about-hero__lead {
  max-width: 62ch;
  margin-top: 20px;
  font-size: 17px;
  line-height: 1.75;
  color: var(--ice-60);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(28px, 5vh, 52px) 0 0;
  background: var(--grid-600);
  border: 1px solid var(--grid-600);
}

.page-about .about-stats__item {
  margin: 0;
  padding: 18px 16px;
  background: var(--navy-800);
  transition: background var(--t-base);
}

.page-about .about-stats__item:hover {
  background: var(--navy-700);
}

.page-about .about-stats__key {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ice-60);
}

.page-about .about-stats__val {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin: 10px 0 0;
}

.page-about .about-stats__unit {
  font-size: 12px;
  color: var(--ice-60);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-body {
  display: grid;
  gap: 40px;
  padding-top: clamp(40px, 7vh, 88px);
}

/* ---------- 左侧章节索引 ---------- */
.page-about .about-rail {
  align-self: start;
}

.page-about .about-rail__title {
  margin: 0 0 10px;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ice-60);
}

.page-about .about-rail__list {
  display: flex;
  gap: 0;
  margin: 0;
  padding: 0;
  overflow-x: auto;
  list-style: none;
  background: var(--navy-800);
  border: 1px solid var(--grid-600);
  -webkit-overflow-scrolling: touch;
}

.page-about .about-rail__item {
  flex: 0 0 auto;
}

.page-about .about-rail__link {
  display: block;
  padding: 12px 16px;
  font-size: 14px;
  white-space: nowrap;
  color: var(--ice-60);
  border-right: 1px solid var(--grid-600);
  transition: color var(--t-link), background var(--t-base);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--cyan-400);
  background: var(--navy-700);
}

.page-about .about-rail__no {
  display: inline-block;
  margin-right: 8px;
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--cyan-700);
}

/* ---------- 通用段落 ---------- */
.page-about .about-lead {
  max-width: 66ch;
  margin: 0;
  font-size: 17px;
  line-height: 1.75;
  color: var(--ice-100);
}

.page-about .about-intro {
  max-width: 62ch;
  margin: 0 0 clamp(24px, 4vh, 40px);
  font-size: 17px;
  line-height: 1.75;
  color: var(--ice-60);
}

.page-about .about-jump {
  margin: 20px 0 0;
  font-size: 14px;
  color: var(--ice-60);
}

.page-about .about-jump a {
  color: var(--cyan-400);
}

/* ---------- 三条业务线 ---------- */
.page-about .about-lines {
  display: grid;
  gap: 24px;
}

.page-about .about-line h3 {
  margin: 0 0 8px;
}

.page-about .about-line p {
  margin: 0;
  color: var(--ice-60);
  line-height: 1.75;
}

/* ---------- V4 认证 ---------- */
.page-about .about-cert {
  display: grid;
  gap: 32px;
}

.page-about .about-cert__cards {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--grid-600);
  border: 1px solid var(--grid-600);
}

.page-about .about-cert__card {
  padding: 22px 20px;
  background: var(--navy-800);
  transition: background var(--t-base);
}

.page-about .about-cert__card:hover {
  background: var(--navy-700);
}

.page-about .about-cert__no {
  display: block;
  margin-bottom: 10px;
  color: var(--cyan-400);
  font-size: 14px;
}

.page-about .about-cert__card h3 {
  margin: 0 0 10px;
}

.page-about .about-cert__card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ice-60);
}

/* ---------- 图版 ---------- */
.page-about .about-figure {
  margin: 0;
  background: var(--charcoal-900);
  border: 1px solid var(--grid-600);
  transition: border-color var(--t-base);
}

.page-about .about-figure:hover {
  border-color: var(--cyan-400);
}

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

.page-about .about-figure .nx-media__caption {
  padding: 10px 14px;
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--ice-60);
  border-top: var(--line);
}

/* ---------- 生产机制 ---------- */
.page-about .about-make {
  display: grid;
  gap: 28px;
}

.page-about .about-make__text p {
  margin: 0 0 18px;
  line-height: 1.75;
  color: var(--ice-60);
}

.page-about .about-make__text p:last-of-type {
  margin-bottom: 0;
}

/* ---------- 时间线 ---------- */
.page-about .about-log {
  margin: 0;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--grid-600);
}

.page-about .about-log__item {
  display: grid;
  gap: 8px;
  position: relative;
  padding: 24px 0 24px 20px;
  transition: background var(--t-base);
}

.page-about .about-log__item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 32px;
  width: 9px;
  height: 9px;
  background: var(--navy-950);
  border: 1px solid var(--cyan-700);
  transition: background var(--t-fast), border-color var(--t-fast);
}

.page-about .about-log__item:hover::before,
.page-about .about-log__item:focus-within::before {
  background: var(--cyan-400);
  border-color: var(--cyan-400);
}

.page-about .about-log__item + .about-log__item {
  border-top: 1px solid var(--grid-600);
}

.page-about .about-log__year {
  font-family: var(--f-mono);
  font-size: 14px;
  letter-spacing: 0.06em;
  color: var(--signal-500);
}

.page-about .about-log__main h3 {
  margin: 0 0 8px;
}

.page-about .about-log__main p {
  margin: 0;
  color: var(--ice-60);
  line-height: 1.75;
}

.page-about .about-log__extra {
  max-height: 0;
  overflow: hidden;
  margin-top: 0;
  font-size: 14px;
  color: var(--cyan-700);
  transition: max-height var(--t-base), margin-top var(--t-base);
}

.page-about .about-log__item:hover .about-log__extra,
.page-about .about-log__item:focus-within .about-log__extra {
  max-height: 160px;
  margin-top: 10px;
}

.page-about .about-log__figure {
  list-style: none;
  padding: 0 0 0 20px;
}

/* ---------- 收录范围 ---------- */
.page-about .about-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 22px 0;
}

.page-about .about-scope {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--grid-600);
  border: 1px solid var(--grid-600);
}

.page-about .about-scope__cell {
  display: grid;
  gap: 8px;
  padding: 18px 16px;
  background: var(--charcoal-900);
}

.page-about .about-scope__key {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ice-60);
}

.page-about .about-scope__note {
  font-size: 13px;
  line-height: 1.6;
  color: var(--ice-60);
}

/* ---------- 团队与联络 ---------- */
.page-about .about-team {
  display: grid;
  gap: 24px;
}

.page-about .about-team .nx-panel h3 {
  margin: 0 0 12px;
}

.page-about .about-team .nx-panel p {
  margin: 0 0 14px;
  line-height: 1.75;
  color: var(--ice-60);
}

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

.page-about .about-contact__row {
  display: grid;
  gap: 4px;
  padding: 12px 0;
  border-bottom: 1px solid var(--grid-600);
}

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

.page-about .about-contact__row dt {
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ice-60);
}

.page-about .about-contact__row dd {
  margin: 0;
  font-size: 15px;
  color: var(--ice-100);
  word-break: break-word;
}

.page-about .about-contact__row dd a {
  color: var(--cyan-400);
}

.page-about .about-contact__note {
  display: block;
  margin-top: 4px;
  font-size: 13px;
  color: var(--ice-60);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-lines {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 32px;
  }

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

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

  .page-about .about-log__item {
    grid-template-columns: 150px minmax(0, 1fr);
    gap: 24px;
    padding-left: 24px;
  }

  .page-about .about-log__figure {
    padding-left: 24px;
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
    gap: 28px;
  }

  .page-about .about-contact__row {
    grid-template-columns: 110px minmax(0, 1fr);
    align-items: baseline;
    gap: 16px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 64px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    overflow: visible;
    background: transparent;
    border: 0;
    border-left: 1px solid var(--grid-600);
  }

  .page-about .about-rail__item {
    flex: none;
  }

  .page-about .about-rail__link {
    position: relative;
    padding: 14px 12px 14px 22px;
    border-right: 0;
    border-bottom: 1px solid var(--grid-600);
  }

  .page-about .about-rail__link::before {
    content: "";
    position: absolute;
    left: -5px;
    top: 50%;
    width: 9px;
    height: 9px;
    transform: translateY(-50%);
    background: var(--navy-950);
    border: 1px solid var(--cyan-700);
    transition: background var(--t-fast), border-color var(--t-fast);
  }

  .page-about .about-rail__link:hover::before,
  .page-about .about-rail__link:focus-visible::before {
    background: var(--cyan-400);
    border-color: var(--cyan-400);
  }

  .page-about .about-cert {
    grid-template-columns: minmax(0, 1fr) 280px;
    gap: 40px;
    align-items: start;
  }

  .page-about .about-make {
    grid-template-columns: minmax(0, 400px) minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-log__item {
    grid-template-columns: 180px minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-stats__item,
  .page-about .about-cert__card,
  .page-about .about-figure,
  .page-about .about-log__item::before,
  .page-about .about-rail__link,
  .page-about .about-rail__link::before,
  .page-about .about-log__extra {
    transition: none;
  }
}