.page-about {
  display: block;
}

/* ===== 面包屑 ===== */
.page-about .about-crumb {
  padding-top: clamp(96px, 14vw, 132px);
  padding-bottom: 6px;
}

/* ===== 首屏 ===== */
.page-about .about-hero {
  padding-top: clamp(10px, 2vw, 22px);
}

.page-about .about-hero__inner {
  display: grid;
  gap: 30px;
  align-items: end;
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  font-size: clamp(30px, 8.4vw, 58px);
  font-weight: 800;
  line-height: 1.14;
  letter-spacing: -0.02em;
  color: var(--og-ink);
}

.page-about .about-hero__lead {
  margin-top: 18px;
  color: var(--og-ink-soft);
}

.page-about .about-hero__facts {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--og-rule);
  border: 1px solid var(--og-rule);
  border-radius: var(--og-radius);
  overflow: hidden;
}

.page-about .about-hero__fact {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px 16px;
  background: var(--og-panel);
}

.page-about .about-hero__num {
  font-size: 22px;
  font-weight: 700;
  color: var(--og-cyan);
  letter-spacing: 0.01em;
}

.page-about .about-hero__key {
  font-size: 13px;
  color: var(--og-ink-dim);
  letter-spacing: 0.02em;
}

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

/* ===== 阶段索引条 ===== */
.page-about .about-index {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding: 6px 2px 14px;
  margin-top: clamp(30px, 5vw, 54px);
  border-top: 1px solid var(--og-rule);
  border-bottom: 1px solid var(--og-rule);
  scrollbar-width: none;
}

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

.page-about .about-index__link {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 9px 14px;
  border-radius: 999px;
  border: 1px solid var(--og-rule);
  background: var(--og-panel);
  color: var(--og-ink-soft);
  font-size: 13.5px;
  letter-spacing: 0.02em;
  text-decoration: none;
  transition: color var(--og-fast) var(--og-ease),
              border-color var(--og-fast) var(--og-ease),
              transform var(--og-fast) var(--og-ease);
}

.page-about .about-index__link .og-mono {
  color: var(--og-cyan);
  font-size: 12px;
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--og-ink);
  border-color: var(--og-cyan);
  transform: translateY(-2px);
}

/* ===== 阶段纵向轨道 ===== */
.page-about .about-track {
  display: block;
}

.page-about .about-stage {
  position: relative;
  padding-block: clamp(38px, 6vw, 72px);
}

.page-about .about-stage + .about-stage {
  border-top: 1px solid var(--og-rule);
}

.page-about .about-stage__grid {
  align-items: start;
}

/* 侧栏注释 */
.page-about .about-note {
  position: relative;
  padding-left: 20px;
  border-left: 1px solid var(--og-rule);
  margin-bottom: 22px;
}

.page-about .about-note::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 -1px;
  width: 1px;
  background: linear-gradient(180deg, var(--og-cyan), transparent 72%);
  opacity: .55;
}

.page-about .about-note__dot {
  position: absolute;
  left: -5px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--og-cyan);
  box-shadow: 0 0 0 4px rgba(37, 230, 208, .14);
}

.page-about .about-note__no {
  display: block;
  font-size: 13px;
  color: var(--og-ink-dim);
  letter-spacing: 0.14em;
}

.page-about .about-note__label {
  margin: 6px 0 12px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--og-ink);
}

.page-about .about-note__meta {
  margin: 0;
  display: grid;
  gap: 9px;
}

.page-about .about-note__row {
  display: grid;
  gap: 2px;
}

.page-about .about-note__row dt {
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--og-ink-dim);
}

.page-about .about-note__row dd {
  margin: 0;
  font-size: 14px;
  color: var(--og-ink-soft);
  line-height: 1.6;
}

/* 正文列 */
.page-about .about-body {
  min-width: 0;
}

.page-about .about-body__title {
  margin: 0 0 18px;
  font-size: clamp(22px, 4.4vw, 34px);
  font-weight: 800;
  line-height: 1.28;
  letter-spacing: -0.015em;
  color: var(--og-ink);
}

.page-about .about-body .og-prose + .og-prose {
  margin-top: 16px;
}

.page-about .about-body__media {
  margin: 24px 0 24px;
}

.page-about .about-link {
  color: var(--og-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(37, 230, 208, .42);
  padding-bottom: 1px;
  transition: border-color var(--og-fast) var(--og-ease),
              color var(--og-fast) var(--og-ease);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--og-cyan-lift);
  border-color: var(--og-cyan-lift);
}

/* 分类色标行 */
.page-about .about-legend {
  list-style: none;
  margin: 20px 0 22px;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* 暖纸摘要板 */
.page-about .about-paper {
  margin: 22px 0 22px;
  color: var(--og-deep);
}

.page-about .about-paper__kicker {
  margin: 0 0 14px;
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: rgba(8, 12, 22, .58);
}

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

.page-about .about-paper__item {
  display: flex;
  align-items: baseline;
  gap: 12px;
  font-size: 15px;
  line-height: 1.6;
  color: var(--og-deep);
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(8, 12, 22, .12);
}

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

.page-about .about-paper__no {
  color: rgba(8, 12, 22, .45);
  font-size: 12px;
  letter-spacing: 0.1em;
}

/* 迭代折线图 */
.page-about .about-chart {
  margin: 26px 0;
  padding: 20px 18px 14px;
  border: 1px solid var(--og-rule);
  border-radius: var(--og-radius-lg);
  background:
    radial-gradient(120% 140% at 100% 0%, rgba(142, 107, 255, .16), transparent 62%),
    var(--og-panel);
}

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

.page-about .about-chart__axis {
  stroke: var(--og-rule);
  stroke-width: 1;
}

.page-about .about-chart__line {
  fill: none;
  stroke: var(--og-cyan);
  stroke-width: 2.4;
  stroke-linecap: round;
  stroke-linejoin: round;
  filter: drop-shadow(0 0 6px rgba(37, 230, 208, .4));
}

.page-about .about-chart__dot {
  fill: var(--og-violet);
}

.page-about .about-chart__dot--now {
  fill: var(--og-cyan);
  filter: drop-shadow(0 0 8px rgba(37, 230, 208, .7));
}

.page-about .about-chart figcaption {
  margin-top: 12px;
}

/* ===== 结尾入口 ===== */
.page-about .about-outro {
  padding-block: clamp(46px, 7vw, 88px);
  border-top: 1px solid var(--og-rule);
  background:
    radial-gradient(90% 120% at 12% 0%, rgba(255, 138, 61, .12), transparent 60%),
    radial-gradient(80% 120% at 88% 100%, rgba(37, 230, 208, .1), transparent 62%);
}

.page-about .about-outro__head {
  max-width: 620px;
}

.page-about .about-outro__title {
  margin: 12px 0 0;
  font-size: clamp(24px, 5vw, 38px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.015em;
  color: var(--og-ink);
}

.page-about .about-outro__list {
  list-style: none;
  margin: 32px 0 0;
  padding: 0;
  display: grid;
  gap: 16px;
  grid-template-columns: 1fr;
}

.page-about .about-outro__item {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 22px 20px 24px;
  border: 1px solid var(--og-rule);
  border-radius: var(--og-radius);
  background: var(--og-panel);
  transition: transform var(--og-fast) var(--og-ease),
              border-color var(--og-fast) var(--og-ease);
}

.page-about .about-outro__item:hover {
  transform: translateY(-3px);
  border-color: rgba(37, 230, 208, .5);
}

.page-about .about-outro__item-title {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--og-ink);
}

.page-about .about-outro__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--og-ink-dim);
}

.page-about .about-outro__item .og-btn {
  align-self: flex-start;
  margin-top: 6px;
}

/* ===== 响应式 ===== */
@media (min-width: 700px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-outro__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: clamp(32px, 5vw, 76px);
  }

  .page-about .about-note {
    position: sticky;
    top: 118px;
    margin-bottom: 0;
  }

  .page-about .about-body__media {
    margin-top: 8px;
  }

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

@media (min-width: 1180px) {
  .page-about .about-hero__title {
    max-width: 15em;
  }

  .page-about .about-body {
    padding-right: clamp(0px, 2vw, 26px);
  }
}