.page-about {
  --pa-rail-w: 216px;
  --pa-ink-line: 1px solid var(--line);
  display: block;
  background: var(--ink);
  color: var(--text);
  font-family: var(--sans);
}

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

/* ------------------------------------------------------------------ 首屏 */

.page-about .about-hero {
  position: relative;
  padding: 28px 0 44px;
  background:
    radial-gradient(120% 90% at 88% -10%, rgba(201, 162, 75, .16), rgba(10, 12, 16, 0) 58%),
    linear-gradient(180deg, rgba(14, 42, 34, .55) 0%, rgba(10, 12, 16, 0) 340px);
  border-bottom: 2px solid var(--line);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 6px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--gold) 0 2px,
    transparent 2px 14px
  );
  opacity: .45;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 2px;
  background: linear-gradient(90deg, var(--gold), transparent 42%, transparent 58%, var(--blue));
  opacity: .5;
}

.page-about .about-hero .breadcrumbs {
  margin-bottom: 26px;
}

.page-about .about-hero__title {
  margin: 12px 0 0;
  font-size: clamp(2.1rem, 5.4vw, 4rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -.015em;
  color: var(--white-soft);
}

.page-about .about-hero__accent {
  color: var(--gold-hi);
  position: relative;
}

.page-about .about-hero__accent::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: .06em;
  height: 3px;
  background: var(--neon);
  opacity: .7;
}

.page-about .about-hero__lede {
  margin: 22px 0 0;
  max-width: 46ch;
  font-size: clamp(1rem, 1.45vw, 1.125rem);
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  border: var(--pa-ink-line);
  border-left: 3px solid var(--gold);
  background: rgba(20, 25, 32, .72);
}

.page-about .about-hero__facts li {
  flex: 1 1 168px;
  min-width: 0;
  padding: 12px 16px;
  border-right: var(--pa-ink-line);
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.page-about .about-hero__facts li:last-child {
  border-right: 0;
}

.page-about .about-hero__key {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--muted);
}

.page-about .about-hero__val {
  font-size: 15px;
  font-weight: 700;
  color: var(--white-soft);
  letter-spacing: .01em;
}

/* ------------------------------------------------------------ 关键数字带 */

.page-about .about-band {
  border-bottom: 2px solid var(--line);
  background: var(--panel-deep);
}

.page-about .about-band__inner {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  padding: 1px 0;
}

.page-about .about-band__cell {
  background: var(--panel-deep);
  padding: 18px 16px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.page-about .about-band__num {
  font-family: var(--mono);
  font-size: clamp(1.5rem, 3.4vw, 2.15rem);
  font-weight: 700;
  letter-spacing: .01em;
  line-height: 1;
  color: var(--gold-hi);
}

.page-about .about-band__cap {
  font-size: 13px;
  color: var(--muted);
  letter-spacing: .02em;
}

/* -------------------------------------------------------------- 主栅格 */

.page-about .about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  padding-top: 34px;
  padding-bottom: 72px;
}

.page-about .about-main {
  min-width: 0;
  max-width: 860px;
}

/* 左侧索引栏 */

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

.page-about .about-rail__label {
  margin: 0 0 10px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--gold);
  text-transform: uppercase;
}

.page-about .index-rail {
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--line) transparent;
}

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

.page-about .index-rail__link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: var(--pa-ink-line);
  border-left: 3px solid var(--line);
  color: var(--muted);
  text-decoration: none;
  font-size: 13px;
  white-space: nowrap;
  background: rgba(20, 25, 32, .5);
  transition:
    border-color .2s var(--ease),
    color .2s var(--ease),
    background-color .2s var(--ease);
}

.page-about .index-rail__link:hover {
  border-color: var(--gold);
  border-left-color: var(--gold);
  color: var(--gold-hi);
}

.page-about .index-rail__link:focus-visible {
  outline: 2px solid var(--neon);
  outline-offset: 2px;
}

.page-about .index-rail__link.is-current {
  border-left-color: var(--neon);
  border-color: var(--line);
  background: rgba(59, 255, 158, .07);
  color: var(--white-soft);
}

.page-about .index-rail__num {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--gold);
}

.page-about .index-rail__link.is-current .index-rail__num {
  color: var(--neon);
}

/* ------------------------------------------------------------ 章节骨架 */

.page-about .about-section {
  padding: 38px 0 44px;
  border-top: var(--pa-ink-line);
  scroll-margin-top: calc(var(--header-h) + 28px);
}

.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-section__head {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 22px;
}

.page-about .about-section__num {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--gold);
}

.page-about .about-section__num::after {
  content: "";
  width: 38px;
  height: 1px;
  background: var(--gold);
  opacity: .55;
}

.page-about .about-section__title {
  margin: 0;
  font-size: clamp(1.42rem, 3vw, 2.05rem);
  font-weight: 800;
  line-height: 1.24;
  letter-spacing: -.01em;
  color: var(--white-soft);
}

.page-about .about-section__lede {
  margin: 0;
  max-width: 56ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-section__body p {
  margin: 0 0 16px;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-section__body p:last-child {
  margin-bottom: 0;
}

.page-about .about-section__after {
  margin: 22px 0 0;
  padding: 16px 18px;
  max-width: 62ch;
  border: var(--pa-ink-line);
  border-left: 3px solid var(--blue);
  background: rgba(52, 200, 255, .05);
  font-size: 15px;
  line-height: 1.78;
  color: var(--text);
}

.page-about .about-link {
  color: var(--blue);
  text-decoration: none;
  border-bottom: 1px solid rgba(52, 200, 255, .45);
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--neon);
  border-bottom-color: var(--neon);
}

/* ------------------------------------------------------------ 数字矩阵 */

.page-about .about-numbers {
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: var(--pa-ink-line);
}

.page-about .about-numbers__item {
  background: var(--panel-deep);
  padding: 16px 14px;
  display: flex;
  flex-direction: column;
  gap: 5px;
  min-width: 0;
}

.page-about .about-numbers__v {
  font-family: var(--mono);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.1;
  color: var(--neon);
  letter-spacing: .01em;
}

.page-about .about-numbers__l {
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--muted);
}

/* -------------------------------------------------------------- 图片框 */

.page-about .about-figure {
  position: relative;
  margin: 0 0 24px;
  border: 2px solid var(--line);
  background: var(--panel);
  overflow: hidden;
}

.page-about .about-figure::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(155deg, rgba(201, 162, 75, .14), rgba(10, 12, 16, 0) 46%),
    linear-gradient(320deg, rgba(52, 200, 255, .14), rgba(10, 12, 16, 0) 52%);
}

.page-about .about-figure__img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  aspect-ratio: 8 / 5;
  object-fit: cover;
  filter: saturate(.7) contrast(1.1) brightness(.76);
}

.page-about .about-figure--square .about-figure__img {
  aspect-ratio: 1 / 1;
}

.page-about .about-figure__cap {
  position: relative;
  z-index: 1;
  padding: 9px 12px;
  border-top: var(--pa-ink-line);
  background: var(--panel-deep);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--muted);
}

/* ---------------------------------------------------------- 版本时间轴 */

.page-about .about-figure--band {
  margin-bottom: 20px;
}

.page-about .version-track {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(248px, 272px);
  border: 2px solid var(--line);
  background: var(--panel-deep);
  overflow-x: auto;
  overscroll-behavior-x: contain;
  -webkit-overflow-scrolling: touch;
  scroll-snap-type: x mandatory;
  scrollbar-width: thin;
  scrollbar-color: var(--gold) var(--ink);
}

.page-about .version-track::-webkit-scrollbar {
  height: 8px;
}

.page-about .version-track::-webkit-scrollbar-track {
  background: var(--ink);
}

.page-about .version-track::-webkit-scrollbar-thumb {
  background: var(--gold);
  border-radius: 0;
}

.page-about .version-node {
  position: relative;
  scroll-snap-align: start;
  padding: 26px 20px 26px;
  border-right: var(--pa-ink-line);
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-height: 226px;
  background: linear-gradient(180deg, rgba(20, 25, 32, .9), rgba(16, 21, 27, .55));
}

.page-about .version-node::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--gold);
  opacity: .5;
}

.page-about .version-node::after {
  content: "";
  position: absolute;
  top: 3px;
  left: 20px;
  width: 9px;
  height: 9px;
  margin-top: -4.5px;
  border-radius: 50%;
  background: var(--gold);
  box-shadow: 0 0 0 3px rgba(201, 162, 75, .18);
}

.page-about .version-node--current {
  background: linear-gradient(180deg, rgba(59, 255, 158, .09), rgba(16, 21, 27, .6));
}

.page-about .version-node--current::before {
  background: var(--neon);
  opacity: 1;
}

.page-about .version-node--current::after {
  background: var(--neon);
  box-shadow: 0 0 0 3px rgba(59, 255, 158, .22);
}

.page-about .version-node__tag {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--gold-hi);
}

.page-about .version-node--current .version-node__tag {
  color: var(--neon);
}

.page-about .version-node__title {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.35;
  color: var(--white-soft);
}

.page-about .version-node__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--muted);
}

/* ------------------------------------------------------------ 双栏排版 */

.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
  align-items: start;
}

.page-about .about-split .about-figure {
  margin-bottom: 0;
}

/* ------------------------------------------------------------ 联络信息 */

.page-about .about-contact {
  margin: 0 0 16px;
  border: var(--pa-ink-line);
  border-left: 3px solid var(--gold);
  background: rgba(20, 25, 32, .6);
}

.page-about .about-contact__row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 13px 16px;
  border-bottom: var(--pa-ink-line);
}

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

.page-about .about-contact__key {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--muted);
}

.page-about .about-contact__val {
  margin: 0;
  font-family: var(--mono);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .02em;
  color: var(--white-soft);
  word-break: break-word;
}

.page-about .about-contact__note {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--muted);
}

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

/* ------------------------------------------------------------ 响应式 */

@media (min-width: 700px) {
  .page-about .about-band__inner {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about .about-contact__row {
    grid-template-columns: 120px minmax(0, 1fr);
    align-items: baseline;
    gap: 16px;
  }
}

@media (min-width: 860px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 3fr) minmax(0, 2fr);
    gap: 32px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero {
    padding: 38px 0 60px;
  }

  .page-about .about-grid {
    grid-template-columns: var(--pa-rail-w) minmax(0, 1fr);
    gap: 56px;
    padding-top: 56px;
    padding-bottom: 96px;
  }

  .page-about .about-rail__sticky {
    position: sticky;
    top: calc(var(--header-h) + 26px);
  }

  .page-about .index-rail {
    flex-direction: column;
    gap: 6px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .index-rail__link {
    width: 100%;
    white-space: normal;
    font-size: 13.5px;
    padding: 10px 12px;
  }

  .page-about .about-section {
    padding: 48px 0 52px;
  }

  .page-about .version-track {
    grid-auto-columns: minmax(252px, 1fr);
  }
}

@media (min-width: 1280px) {
  .page-about {
    --pa-rail-w: 234px;
  }

  .page-about .about-section__body p {
    font-size: 17px;
  }

  .page-about .about-section__after {
    font-size: 15.5px;
  }
}

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