.page-about {
  --about-rail: 118px;
  --about-ink: var(--paper);
  --about-ink-2: var(--paper-2);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  background: var(--grad-clear);
  padding: 32px 0 108px;
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 84px;
  background: var(--deep);
  clip-path: polygon(0 100%, 100% 0, 100% 100%);
  pointer-events: none;
}

.page-about .about-hero > .bs-shell {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .bs-breadcrumb {
  margin-bottom: 4px;
}

.page-about .about-hero__grid {
  display: grid;
  gap: 32px;
  margin-top: 26px;
}

.page-about .about-hero__title {
  margin: 12px 0 0;
  color: var(--about-ink);
}

.page-about .about-hero__lede {
  margin: 18px 0 0;
  max-width: 64ch;
  color: var(--about-ink-2);
  font-size: 16px;
  line-height: 1.8;
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  margin-top: 30px;
  border: 1px solid var(--line);
  background: var(--line);
}

.page-about .about-fact {
  background: rgba(10, 27, 46, 0.78);
  padding: 16px 18px;
}

.page-about .about-fact__num {
  display: block;
  font-family: var(--font-num);
  font-variant-numeric: tabular-nums;
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--mint);
}

.page-about .about-fact__label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.55;
  color: var(--muted);
}

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

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 40px 0 128px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 44px;
    align-items: start;
    margin-top: 36px;
  }

  .page-about .about-hero__lede {
    font-size: 18px;
  }
}

/* ---------- 章节框架：左侧年份刻度尺 ---------- */
.page-about .about-chapter {
  position: relative;
}

.page-about .about-chapter__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

.page-about .about-chapter__rail {
  display: none;
}

.page-about .about-chapter__intro {
  margin: 14px 0 0;
  max-width: 66ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--about-ink-2);
}

@media (min-width: 900px) {
  .page-about .about-chapter__grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 0 44px;
  }

  .page-about .about-chapter__rail {
    display: block;
    position: relative;
    align-self: stretch;
    padding: 8px 22px 0 0;
    text-align: right;
    border-right: 1px solid var(--line);
  }

  .page-about .about-chapter__mark {
    display: block;
    font-family: var(--font-num);
    font-variant-numeric: tabular-nums;
    font-size: 12px;
    letter-spacing: 0.16em;
    color: var(--about-ink-2);
  }

  .page-about .about-chapter__dot {
    position: absolute;
    top: 12px;
    right: -4.5px;
    width: 8px;
    height: 8px;
    background: var(--mint);
  }

  .page-about .about-chapter__dot--gold {
    background: var(--gold);
  }
}

/* ---------- 起点与覆盖 ---------- */
.page-about .about-origin {
  margin-top: 22px;
}

.page-about .about-origin p {
  margin: 0 0 1.2em;
  font-size: 16px;
  line-height: 1.8;
  color: var(--about-ink-2);
}

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

.page-about .about-origin__side {
  margin-top: 26px;
}

@media (min-width: 900px) {
  .page-about .about-origin__side {
    margin-top: 4px;
  }
}

/* ---------- 发展节点 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
}

.page-about .about-timeline__item {
  display: grid;
  grid-template-columns: 52px minmax(0, 1fr);
  column-gap: 16px;
  padding-bottom: 26px;
}

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

.page-about .about-timeline__year {
  display: block;
  padding-top: 3px;
  text-align: right;
  font-family: var(--font-num);
  font-variant-numeric: tabular-nums;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--mint);
}

.page-about .about-timeline__item--now .about-timeline__year {
  color: var(--gold);
}

.page-about .about-timeline__card {
  position: relative;
  border-left: 1px solid var(--line);
  padding: 0 0 2px 20px;
}

.page-about .about-timeline__card::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 7px;
  width: 7px;
  height: 7px;
  background: var(--mint);
}

.page-about .about-timeline__item--now .about-timeline__card::before {
  background: var(--gold);
}

.page-about .about-timeline__title {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--about-ink);
}

.page-about .about-timeline__card p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--about-ink-2);
}

@media (min-width: 640px) {
  .page-about .about-timeline__item {
    grid-template-columns: 68px minmax(0, 1fr);
    column-gap: 28px;
    padding-bottom: 32px;
  }

  .page-about .about-timeline__year {
    font-size: 15px;
  }

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

  .page-about .about-timeline__title {
    font-size: 18px;
  }
}

/* ---------- 比赛日值班 ---------- */
.page-about .about-desk {
  margin-top: 20px;
}

.page-about .about-desk .bs-col-6 p {
  margin: 0 0 1.2em;
  font-size: 16px;
  line-height: 1.8;
  color: var(--about-ink-2);
}

.page-about .about-shift {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-shift__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 13px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-shift__time {
  font-family: var(--font-num);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mint);
}

.page-about .about-shift__text {
  font-size: 15px;
  line-height: 1.72;
  color: var(--about-ink-2);
}

.page-about .about-desk__media {
  margin: 26px 0 0;
  padding: 0;
}

.page-about .about-desk__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
}

@media (min-width: 640px) {
  .page-about .about-shift__row {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 18px;
    align-items: baseline;
    padding: 14px 0;
  }
}

@media (min-width: 900px) {
  .page-about .about-desk__media {
    margin-top: 4px;
  }
}

/* ---------- 协作网络：标签页 ---------- */
.page-about .about-net {
  margin-top: 28px;
}

.page-about .bs-tablist {
  display: flex;
  flex-wrap: wrap;
  gap: 1px;
  border-bottom: 1px solid var(--line);
}

.page-about .bs-tab {
  appearance: none;
  -webkit-appearance: none;
  position: relative;
  top: 1px;
  margin: 0;
  padding: 12px 18px;
  border: 1px solid transparent;
  border-bottom: none;
  background: transparent;
  color: var(--muted);
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: color 180ms var(--ease), background-color 180ms var(--ease), border-color 180ms var(--ease);
}

.page-about .bs-tab:hover:not([aria-selected="true"]) {
  color: var(--about-ink);
  background: var(--pitch);
}

.page-about .bs-tab[aria-selected="true"] {
  color: var(--deep);
  background: var(--mint);
  border-color: var(--mint);
}

.page-about .bs-tab:focus-visible {
  outline: 2px solid var(--mint);
  outline-offset: 2px;
}

.page-about .bs-tabpanel[hidden] {
  display: none;
}

.page-about .about-net__panel {
  padding-top: 26px;
}

.page-about .about-net__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
}

.page-about .about-net__text p {
  margin: 0 0 1.2em;
  font-size: 16px;
  line-height: 1.8;
  color: var(--about-ink-2);
}

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

.page-about .about-net__text .bs-title--sm {
  margin: 0 0 14px;
  color: var(--about-ink);
}

.page-about .about-net__media {
  margin: 0;
  padding: 0;
}

.page-about .about-net__media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
}

.page-about .about-net__side {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  align-content: start;
  border: 1px solid var(--line);
  background: var(--line);
}

.page-about .about-net__stat {
  margin: 0;
  padding: 20px 18px;
  background: rgba(18, 49, 79, 0.72);
}

.page-about .about-net__num {
  display: block;
  font-family: var(--font-num);
  font-variant-numeric: tabular-nums;
  font-size: 34px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--mint);
}

.page-about .about-net__stat--gold .about-net__num {
  color: var(--gold);
}

.page-about .about-net__unit {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--muted);
}

@media (min-width: 768px) {
  .page-about .about-net__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.8fr);
    gap: 36px;
    align-items: start;
  }
}

/* ---------- 下一步入口 ---------- */
.page-about .about-next {
  border-top: 1px solid var(--line);
}

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

.page-about .about-next__lead .bs-title {
  margin: 10px 0 0;
  color: var(--about-ink);
}

.page-about .about-next__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-next__link {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 12px;
  align-items: center;
  padding: 16px 10px 16px 0;
  border-bottom: 1px solid var(--line);
  color: var(--about-ink);
  text-decoration: none;
  transition: background-color 160ms var(--ease), padding-left 160ms var(--ease);
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  background: var(--pitch);
  padding-left: 14px;
}

.page-about .about-next__link:focus-visible {
  outline: 2px solid var(--mint);
  outline-offset: -2px;
}

.page-about .about-next__idx {
  font-family: var(--font-num);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--mint);
}

.page-about .about-next__label {
  font-size: 15px;
  line-height: 1.6;
}

@media (min-width: 900px) {
  .page-about .about-next__grid {
    grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
    gap: 52px;
    align-items: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .bs-tab,
  .page-about .about-next__link {
    transition: none;
  }
}
<<<END>>>