.page-about {
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--paper);
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-head);
  letter-spacing: -0.01em;
}

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

.page-about .figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border: 3px solid var(--ink);
  background: var(--card);
}

.page-about .figure__cap {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--ink-2);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 24px 0 48px;
  border-bottom: 2px solid var(--ink);
}

.page-about .about-hero__grid {
  display: grid;
  gap: 32px;
}

.page-about .about-hero__grid > * {
  min-width: 0;
}

.page-about h1 {
  font-size: clamp(30px, 7.4vw, 50px);
  font-weight: 900;
  line-height: 1.16;
  margin: 14px 0 0;
  max-width: 16em;
}

.page-about .about-hero__lead {
  margin: 20px 0 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink-2);
  max-width: 34em;
}

.page-about .hero-facts {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
  border-top: 2px solid var(--line);
  padding-top: 18px;
}

.page-about .hero-facts li {
  display: grid;
  grid-template-columns: 5.6em minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
}

.page-about .hero-facts b {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  color: var(--cyan-deep);
  letter-spacing: 0.02em;
}

.page-about .hero-facts span {
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--ink-2);
}

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

.page-about .about-hero__figure img {
  box-shadow: 8px 8px 0 var(--ink-2);
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    gap: 46px;
    align-items: start;
  }
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  padding: 52px 0;
  border-bottom: 2px solid var(--line);
}

.page-about .chapter__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 22px;
}

.page-about .chapter__no {
  flex: none;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.14em;
  color: var(--ink);
  background: var(--card);
  border: 2px solid var(--ink);
  box-shadow: 3px 3px 0 var(--ink);
  padding: 3px 9px;
}

.page-about .chapter__title {
  font-size: 26px;
  font-weight: 800;
  line-height: 1.3;
  margin: 0;
}

@media (min-width: 768px) {
  .page-about .chapter {
    padding: 68px 0;
  }
  .page-about .chapter__title {
    font-size: 34px;
  }
}

.page-about .about-prose {
  max-width: 64ch;
}

.page-about .about-prose p {
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.82;
  color: var(--ink-2);
}

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

/* ---------- 第二章 分栏 ---------- */
.page-about .chapter__grid {
  display: grid;
  gap: 32px;
}

.page-about .chapter__grid > * {
  min-width: 0;
}

.page-about .chapter__figure {
  margin-top: 4px;
}

@media (min-width: 900px) {
  .page-about .chapter__grid {
    grid-template-columns: minmax(0, 0.94fr) minmax(0, 1.06fr);
    gap: 46px;
    align-items: start;
  }
  .page-about .chapter__figure {
    margin-top: 10px;
  }
}

/* ---------- 第三章 版本时间线 ---------- */
.page-about .track {
  list-style: none;
  margin: 0;
  padding: 6px 2px 20px;
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 80%;
  gap: 16px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

.page-about .track__item {
  position: relative;
  min-width: 0;
  scroll-snap-align: start;
  padding-top: 20px;
  border-top: 2px solid var(--ink);
}

.page-about .track__item::before {
  content: "";
  position: absolute;
  top: -7px;
  left: 0;
  width: 12px;
  height: 12px;
  background: var(--cyan);
  border: 2px solid var(--ink);
  border-radius: 50%;
}

.page-about .track__item--now::before {
  background: var(--orange);
}

.page-about .track__year {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--ink);
}

.page-about .track__title {
  margin: 0 0 9px;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.4;
}

.page-about .track__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--ink-2);
}

.page-about .chapter .about-prose {
  margin-top: 20px;
}

@media (min-width: 900px) {
  .page-about .track {
    grid-auto-flow: row;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    grid-auto-columns: auto;
    gap: 22px;
    overflow: visible;
    padding-bottom: 6px;
  }
}

/* ---------- 第四章 规则卡 ---------- */
.page-about .rules {
  display: grid;
  gap: 18px;
  margin-top: 26px;
}

.page-about .rule {
  background: var(--card);
  border: 2px solid var(--ink);
  box-shadow: 6px 6px 0 var(--ink-2);
  padding: 18px 18px 16px;
  transition: box-shadow 0.22s ease, border-color 0.22s ease;
}

.page-about .rule:hover,
.page-about .rule:focus-within {
  border-color: var(--ink);
  box-shadow: 6px 6px 0 var(--cyan-deep);
}

.page-about .rule:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 4px;
}

.page-about .rule__idx {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--cyan-deep);
}

.page-about .rule__title {
  margin: 0 0 10px;
  font-size: 19px;
  font-weight: 800;
  line-height: 1.4;
}

.page-about .rule__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--ink-2);
}

.page-about .rule__more {
  display: block;
  margin: 12px 0 0;
  padding-top: 12px;
  border-top: 1px dashed var(--line);
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--ink-2);
}

@media (hover: hover) and (pointer: fine) {
  .page-about .rule__more {
    max-height: 0;
    margin-top: 0;
    padding-top: 0;
    border-top-color: transparent;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.28s ease, opacity 0.28s ease, margin-top 0.28s ease, padding-top 0.28s ease;
  }
  .page-about .rule:hover .rule__more,
  .page-about .rule:focus-within .rule__more {
    max-height: 12em;
    margin-top: 12px;
    padding-top: 12px;
    border-top-color: var(--line);
    opacity: 1;
  }
}

@media (min-width: 780px) {
  .page-about .rules {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
  }
  .page-about .rules .rule:nth-child(2) {
    margin-top: 18px;
  }
  .page-about .rules .rule:nth-child(3) {
    margin-top: 36px;
  }
}

/* ---------- 第五章 站点信息 ---------- */
.page-about .station {
  padding: 52px 0;
  border-bottom: 2px solid var(--ink);
}

.page-about .station__grid {
  display: grid;
  gap: 30px;
}

.page-about .station__grid > * {
  min-width: 0;
}

.page-about .station__plate {
  margin-top: 26px;
  background: var(--console);
  color: var(--paper);
  border: 2px solid var(--ink);
  box-shadow: 6px 6px 0 var(--cyan);
  padding: 18px 18px 16px;
}

.page-about .station__plate-tag {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--cyan);
}

.page-about .station__list {
  margin: 0;
  display: grid;
  gap: 11px;
}

.page-about .station__row {
  display: grid;
  grid-template-columns: 5.4em minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(199, 206, 214, 0.28);
}

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

.page-about .station__row dt {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--cyan);
  letter-spacing: 0.04em;
}

.page-about .station__row dd {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.65;
  color: var(--paper);
  word-break: break-word;
}

.page-about .station__figure img {
  box-shadow: 8px 8px 0 var(--ink);
}

@media (min-width: 900px) {
  .page-about .station {
    padding: 68px 0;
  }
  .page-about .station__grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: 46px;
    align-items: start;
  }
  .page-about .station__figure {
    margin-top: 52px;
  }
}

/* ---------- 尾部行动区 ---------- */
.page-about .about-cta {
  padding: 52px 0 60px;
  background: var(--card);
}

.page-about .about-cta__in {
  display: grid;
  gap: 20px;
}

.page-about .about-cta__lead {
  margin: 0;
  font-family: var(--font-head);
  font-size: 22px;
  font-weight: 800;
  line-height: 1.45;
  max-width: 24em;
}

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

@media (min-width: 768px) {
  .page-about .about-cta {
    padding: 64px 0 72px;
  }
  .page-about .about-cta__lead {
    font-size: 26px;
  }
}

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .rule,
  .page-about .rule__more,
  .page-about .track {
    transition: none;
    scroll-behavior: auto;
  }
  .page-about .rule__more {
    max-height: none;
    opacity: 1;
  }
}