.page-about {
  --about-spine: rgba(53, 242, 192, 0.32);
  --about-paper-soft: #EFE4D2;
  padding-bottom: var(--sp-5);
}

.page-about .breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
  padding: var(--sp-4) 0 var(--sp-2);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

/* ---------- 首屏 ---------- */
.page-about .history-hero {
  position: relative;
  max-width: 880px;
  padding: var(--sp-3) 0 var(--sp-2) var(--sp-3);
}

.page-about .history-hero::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  width: 5px;
  height: 84px;
  border-radius: 3px;
  background: linear-gradient(180deg, var(--orange), var(--laterite));
  transform: skewY(-7deg);
}

.page-about .history-hero h1 {
  margin: 0 0 var(--sp-3);
  font-size: clamp(30px, 7.4vw, 56px);
  line-height: 1.1;
  letter-spacing: -0.015em;
  color: var(--paper);
}

.page-about .history-hero .lede {
  max-width: 62ch;
  color: var(--body-ink);
  font-size: 16px;
  line-height: 1.85;
}

.page-about .history-hero__note {
  margin-top: var(--sp-3);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

/* ---------- 四个关键数字 ---------- */
.page-about .history-figures {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--sp-2);
  margin: var(--sp-4) 0;
}

.page-about .history-figure {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: var(--sp-3);
  border: 1px solid var(--hair);
  border-radius: var(--r-soft);
  background: linear-gradient(160deg, rgba(27, 39, 82, 0.9), rgba(7, 12, 31, 0.75));
  overflow: hidden;
  transition: border-color var(--t-fast) var(--ease);
}

.page-about .history-figure::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--mint), rgba(53, 242, 192, 0));
  transform: scaleX(0.28);
  transform-origin: left center;
  transition: transform var(--t-fast) var(--ease);
}

.page-about .history-figure:hover {
  border-color: rgba(255, 122, 47, 0.6);
}

.page-about .history-figure:hover::after {
  transform: scaleX(1);
}

.page-about .history-figure__num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 6vw, 30px);
  font-weight: 600;
  line-height: 1;
  color: var(--mint);
  letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
}

.page-about .history-figure__label {
  font-size: 13px;
  color: var(--mist);
}

.page-about .history-hero__media {
  margin: 0 0 var(--sp-5);
  border-radius: var(--r-card);
  overflow: hidden;
}

/* ---------- 正文骨架 ---------- */
.page-about .history-body {
  margin-top: var(--sp-5);
}

/* ---------- 左侧时间线导航 ---------- */
.page-about .history-rail {
  position: relative;
  padding-left: var(--sp-4);
}

.page-about .history-rail__title {
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--laterite);
  margin: 0 0 var(--sp-2);
}

.page-about .history-rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .history-rail::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 26px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(180deg, var(--about-spine) 0%, rgba(53, 242, 192, 0.14) 55%, rgba(53, 242, 192, 0) 100%);
}

.page-about .history-rail__item a {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: var(--sp-2);
  padding: 9px 0;
  color: var(--mist);
  text-decoration: none;
  font-size: 14px;
  line-height: 1.4;
  transition: color var(--t-fast) var(--ease);
}

.page-about .history-rail__item a::before {
  content: "";
  position: absolute;
  left: calc(-1 * var(--sp-4) + 2px);
  top: 15px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--rail);
  border: 1px solid var(--mint-dim);
  transition: background var(--t-fast) var(--ease), box-shadow var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .history-rail__item a:hover {
  color: var(--mint);
}

.page-about .history-rail__item a:hover::before {
  background: var(--mint);
  border-color: var(--mint);
  box-shadow: 0 0 0 4px rgba(53, 242, 192, 0.16);
}

.page-about .history-rail__num {
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--orange);
}

/* ---------- 章节 ---------- */
.page-about .history-chapter {
  border-top: 1px solid var(--hair);
  padding-top: var(--sp-4);
  margin-bottom: var(--sp-5);
  scroll-margin-top: 96px;
}

.page-about .history-chapter__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--sp-3);
  margin-bottom: var(--sp-2);
}

.page-about .history-chapter__num {
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--orange);
}

.page-about .history-chapter__year {
  font-family: var(--font-mono);
  font-size: clamp(26px, 8vw, 52px);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.03em;
  color: rgba(244, 235, 220, 0.13);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.page-about .history-chapter h2 {
  margin: 0 0 var(--sp-3);
  max-width: 20ch;
  font-size: clamp(23px, 4.6vw, 34px);
  line-height: 1.26;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .history-chapter p {
  max-width: 68ch;
  margin: 0 0 var(--sp-3);
  font-size: 16px;
  line-height: 1.85;
  color: var(--body-ink);
}

/* ---------- 等宽数据块 ---------- */
.page-about .history-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 1px;
  margin: var(--sp-4) 0 var(--sp-2);
  border: 1px solid var(--hair);
  border-radius: var(--r-soft);
  background: var(--hair);
  overflow: hidden;
}

.page-about .history-stats__row {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: var(--sp-3);
  background: rgba(27, 39, 82, 0.72);
}

.page-about .history-stats__key {
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
}

.page-about .history-stats__val {
  font-family: var(--font-mono);
  font-size: 21px;
  font-weight: 600;
  line-height: 1.1;
  color: var(--mint);
  font-variant-numeric: tabular-nums;
}

/* ---------- 折线图 ---------- */
.page-about .history-chart {
  margin: var(--sp-4) 0;
  padding: var(--sp-3);
  border: 1px solid var(--hair);
  border-radius: var(--r-card);
  background: linear-gradient(180deg, rgba(27, 39, 82, 0.7), rgba(7, 12, 31, 0.72));
}

.page-about .history-chart__svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .history-chart__grid line {
  stroke: var(--grid-line);
  stroke-width: 1;
}

.page-about .history-chart__area {
  fill: rgba(53, 242, 192, 0.14);
}

.page-about .history-chart__line {
  fill: none;
  stroke: var(--mint);
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.page-about .history-chart__node circle {
  fill: var(--mint);
  transform-box: fill-box;
  transform-origin: center;
  transition: transform var(--t-fast) var(--ease), fill var(--t-fast) var(--ease);
}

.page-about .history-chart__node:hover circle {
  transform: scale(1.8);
  fill: var(--orange);
}

.page-about .history-chart__node text {
  font-family: var(--font-mono);
  font-size: 13px;
  fill: var(--mist);
  letter-spacing: 0.04em;
}

.page-about .history-chart__caption {
  margin-top: var(--sp-2);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 可展开年份摘要 ---------- */
.page-about .history-folds {
  margin-top: var(--sp-3);
}

.page-about .history-folds .fold {
  border: 1px solid var(--hair);
  border-radius: var(--r-soft);
  background: rgba(27, 39, 82, 0.5);
  padding: 0 var(--sp-3);
  transition: border-color var(--t-fast) var(--ease);
}

.page-about .history-folds .fold + .fold {
  margin-top: var(--sp-2);
}

.page-about .history-folds .fold[open] {
  border-color: rgba(255, 122, 47, 0.42);
}

.page-about .history-folds .fold summary {
  padding: var(--sp-3) 0;
  cursor: pointer;
  font-weight: 700;
  font-size: 15px;
  line-height: 1.5;
  color: var(--paper);
}

.page-about .history-folds .fold__body p {
  margin: 0 0 var(--sp-3);
  font-size: 15px;
  line-height: 1.8;
  color: var(--body-ink);
  max-width: 66ch;
}

/* ---------- 图文两栏 ---------- */
.page-about .history-split {
  display: grid;
  gap: var(--sp-3);
  margin: var(--sp-3) 0 var(--sp-2);
}

.page-about .history-split__media {
  border-radius: var(--r-card);
  overflow: hidden;
}

.page-about .history-split__text p {
  max-width: 62ch;
}

/* ---------- 顶部返回 ---------- */
.page-about .history-toplink {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: var(--sp-2);
  padding: 9px 16px;
  border: 1px solid var(--hair);
  border-radius: var(--r-pill);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--mist);
  text-decoration: none;
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .history-toplink:hover {
  color: var(--mint);
  border-color: var(--mint);
}

/* ---------- 收尾纸页 ---------- */
.page-about .history-closing {
  margin-top: var(--sp-5);
  padding: var(--sp-4) var(--sp-3);
  border-radius: var(--r-card);
}

.page-about .history-closing__eyebrow {
  color: var(--laterite);
}

.page-about .history-closing h2 {
  margin: var(--sp-2) 0 var(--sp-3);
  max-width: 18ch;
  font-size: clamp(24px, 4.6vw, 34px);
  line-height: 1.24;
  color: var(--brown);
}

.page-about .history-closing p {
  max-width: 68ch;
  font-size: 16px;
  line-height: 1.85;
  color: #4A3A31;
}

.page-about .history-closing__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
  margin-top: var(--sp-4);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .history-figures {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: var(--sp-3);
  }

  .page-about .history-split {
    grid-template-columns: minmax(0, 0.88fr) minmax(0, 1.12fr);
    align-items: start;
    gap: var(--sp-4);
  }

  .page-about .history-split__media {
    order: -1;
  }

  .page-about .history-closing {
    padding: var(--sp-5) var(--sp-4);
  }
}

@media (max-width: 979px) {
  .page-about .history-rail {
    padding: 0 0 var(--sp-2);
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }

  .page-about .history-rail::-webkit-scrollbar {
    display: none;
  }

  .page-about .history-rail::before {
    display: none;
  }

  .page-about .history-rail__title {
    display: none;
  }

  .page-about .history-rail__list {
    display: flex;
    gap: var(--sp-1);
    padding-bottom: 4px;
  }

  .page-about .history-rail__item {
    flex: 0 0 auto;
    scroll-snap-align: start;
  }

  .page-about .history-rail__item a {
    padding: 8px 15px;
    border: 1px solid var(--hair);
    border-radius: var(--r-pill);
    background: var(--rail);
    white-space: nowrap;
    font-size: 13px;
  }

  .page-about .history-rail__item a::before {
    display: none;
  }

  .page-about .history-rail__item a:hover {
    border-color: var(--mint);
  }

  .page-about .history-body {
    margin-top: var(--sp-4);
  }
}

@media (max-width: 520px) {
  .page-about .history-hero {
    padding-left: var(--sp-3);
  }

  .page-about .history-chapter__head {
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
  }

  .page-about .history-stats {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .history-chart {
    padding: var(--sp-2);
  }

  .page-about .history-closing__links .btn {
    flex: 1 1 auto;
    justify-content: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .history-figure,
  .page-about .history-figure::after,
  .page-about .history-rail__item a,
  .page-about .history-rail__item a::before,
  .page-about .history-chart__node circle,
  .page-about .history-toplink,
  .page-about .history-folds .fold {
    transition: none;
  }
}