.page-about {
  --about-rail-w: 0px;
  --about-sticky-top: calc(var(--bar-h) + 28px);
  --about-panel: rgba(42, 59, 50, 0.42);
  background: var(--bg);
  color: var(--paper);
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  margin: 22px 0 6px;
}

/* ---------- 首屏框景 ---------- */
.page-about .about-hero {
  position: relative;
  margin: 10px 0 56px;
  padding: 26px 20px 30px;
  border: 1px solid var(--line);
  background:
    linear-gradient(158deg, rgba(42, 59, 50, 0.62) 0%, rgba(14, 26, 22, 0.18) 62%);
}

.page-about .about-hero::before,
.page-about .about-hero::after {
  content: "";
  position: absolute;
  width: 24px;
  height: 24px;
  border: 2px solid var(--lime);
  opacity: 0.75;
}

.page-about .about-hero::before {
  top: -1px;
  left: -1px;
  border-right: 0;
  border-bottom: 0;
}

.page-about .about-hero::after {
  right: -1px;
  bottom: -1px;
  border-top: 0;
  border-left: 0;
}

.page-about .about-hero__title {
  margin: 12px 0 18px;
  font-family: var(--font-display);
  font-size: clamp(30px, 7.2vw, 56px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero__lead {
  max-width: 62ch;
  margin: 0;
  font-size: 17px;
  line-height: 1.75;
  color: var(--pale);
}

.page-about .about-hero__note {
  max-width: 62ch;
  margin: 16px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--clay);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.9;
  letter-spacing: 0.04em;
  color: var(--rock);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 14px;
  margin: 26px 0 0;
  padding: 20px 0 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.page-about .stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 500;
  line-height: 1.2;
  color: var(--lime);
}

.page-about .stat-label {
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.05em;
  color: var(--rock);
}

/* ---------- 编号章节骨架 ---------- */
.page-about .chapter {
  margin: 0 0 64px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(var(--bar-h) + 18px);
}

.page-about .chapter-rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 14px;
}

.page-about .chapter-num {
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--rock);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 160ms ease, border-color 160ms ease;
}

.page-about .chapter-num:hover,
.page-about .chapter-num:focus-visible {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

.page-about .chapter-note {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--rock);
}

.page-about .chapter:target {
  border-top-color: var(--lime);
}

.page-about .chapter:target .chapter-num {
  color: var(--lime);
}

.page-about .chapter-title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-size: clamp(23px, 5.4vw, 34px);
  font-weight: 700;
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .chapter-lead {
  max-width: 62ch;
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--pale);
}

.page-about .chapter-body .prose {
  margin: 0 0 22px;
}

.page-about .chapter-body .prose p {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--pale);
}

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

/* ---------- 时间线 ---------- */
.page-about .timeline {
  margin: 22px 0 26px;
  padding: 0 0 0 20px;
  border-left: 1px solid var(--line);
  list-style: none;
}

.page-about .tl-item {
  position: relative;
  padding: 15px 0 17px;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  top: 23px;
  left: -25px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--rock);
  box-shadow: 0 0 0 3px var(--bg);
  transition: background 160ms ease, box-shadow 160ms ease;
}

.page-about .tl-item.is-current::before {
  background: var(--lime);
  box-shadow: 0 0 0 3px var(--bg), 0 0 12px rgba(198, 255, 61, 0.55);
}

.page-about .tl-item:hover::before,
.page-about .tl-item:focus-within::before {
  background: var(--clay);
  box-shadow: 0 0 0 3px var(--bg);
}

.page-about .tl-item.is-current:hover::before {
  background: var(--lime);
}

.page-about .tl-year {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--clay);
}

.page-about .tl-title {
  margin: 7px 0 8px;
  font-size: 17px;
  font-weight: 600;
  line-height: 1.45;
  color: var(--paper);
}

.page-about .tl-text {
  margin: 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.7;
  color: var(--pale);
}

.page-about .tl-note {
  margin: 8px 0 0;
  max-width: 58ch;
  font-size: 13px;
  line-height: 1.7;
  color: var(--rock);
  opacity: 0.6;
  transition: opacity 180ms ease, color 180ms ease;
}

.page-about .tl-item:hover .tl-note,
.page-about .tl-item:focus-within .tl-note {
  opacity: 1;
  color: var(--pale);
}

/* ---------- 图片框 ---------- */
.page-about .about-figure {
  margin: 24px 0 26px;
  position: relative;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--radius);
}

.page-about .about-figure .mlabel {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--pale);
}

/* ---------- 三班切换 ---------- */
.page-about .shift-tabs {
  position: relative;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: 8px 0 22px;
  border: 1px solid var(--line);
  background: var(--about-panel);
}

.page-about .tab-radio {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.page-about .tab-label {
  display: flex;
  flex-direction: column;
  gap: 3px;
  padding: 13px 8px;
  border-right: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--rock);
  text-align: center;
  cursor: pointer;
  transition: background 160ms ease, color 160ms ease;
}

.page-about .tab-label:last-of-type {
  border-right: 0;
}

.page-about .tab-sub {
  font-size: 10px;
  letter-spacing: 0.04em;
  color: var(--rock);
  opacity: 0.8;
}

.page-about .tab-label:hover {
  color: var(--paper);
}

.page-about .tab-radio:checked + .tab-label {
  background: var(--lime);
  color: var(--ink);
}

.page-about .tab-radio:checked + .tab-label .tab-sub {
  color: rgba(18, 17, 15, 0.7);
  opacity: 1;
}

.page-about .tab-radio:focus-visible + .tab-label {
  outline: 2px solid var(--lime);
  outline-offset: -3px;
}

.page-about .shift-panels {
  grid-column: 1 / -1;
  border-top: 1px solid var(--line);
}

.page-about .shift-panel {
  display: none;
  padding: 20px 16px 22px;
  animation: about-fade 180ms ease both;
}

.page-about .shift-panel--morning {
  display: block;
}

.page-about #shift-mid:checked ~ .shift-panels .shift-panel--mid,
.page-about #shift-night:checked ~ .shift-panels .shift-panel--night {
  display: block;
}

.page-about #shift-mid:checked ~ .shift-panels .shift-panel--morning,
.page-about #shift-night:checked ~ .shift-panels .shift-panel--morning {
  display: none;
}

.page-about .shift-title {
  margin: 0 0 10px;
  font-size: 17px;
  font-weight: 600;
  line-height: 1.45;
  color: var(--lime);
}

.page-about .shift-panel p {
  margin: 0 0 12px;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--pale);
}

.page-about .shift-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 7px;
}

.page-about .shift-list li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  line-height: 1.65;
  color: var(--pale);
}

.page-about .shift-list li::before {
  content: "";
  position: absolute;
  top: 9px;
  left: 0;
  width: 7px;
  height: 1px;
  background: var(--pulse);
}

@keyframes about-fade {
  from {
    opacity: 0;
    transform: translateX(8px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* ---------- 三道校准 ---------- */
.page-about .calib-steps {
  display: grid;
  gap: 14px;
  margin: 8px 0 4px;
}

.page-about .calib-step {
  position: relative;
  padding: 18px 16px 18px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--clay);
  background: var(--about-panel);
}

.page-about .calib-num {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--clay);
}

.page-about .calib-title {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .calib-step p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--pale);
}

/* ---------- 荣誉与累计 ---------- */
.page-about .honor-list {
  margin: 8px 0 24px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.page-about .honor-item {
  padding: 18px 16px;
  border: 1px solid var(--line);
  background: linear-gradient(140deg, rgba(180, 116, 79, 0.14), rgba(42, 59, 50, 0.35));
}

.page-about .honor-year {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--clay);
}

.page-about .honor-name {
  margin: 8px 0 8px;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.4;
  color: var(--lime);
}

.page-about .honor-item p {
  margin: 0;
  max-width: 58ch;
  font-size: 14px;
  line-height: 1.75;
  color: var(--pale);
}

.page-about .about-tally {
  display: grid;
  grid-template-columns: repeat(1, minmax(0, 1fr));
  gap: 1px;
  margin: 0 0 22px;
  border: 1px solid var(--line);
  background: var(--line-soft);
}

.page-about .tally-item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 14px;
  background: var(--bg);
}

.page-about .tally-num {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 500;
  color: var(--pulse);
}

.page-about .tally-label {
  font-size: 13px;
  line-height: 1.6;
  color: var(--rock);
}

/* ---------- 结尾行动区 ---------- */
.page-about .about-cta {
  margin: 0 0 56px;
  padding: 30px 20px 32px;
  background: var(--lime);
  color: var(--ink);
  border-radius: var(--radius);
}

.page-about .about-cta__kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: rgba(18, 17, 15, 0.62);
}

.page-about .about-cta__title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-size: clamp(22px, 5.2vw, 32px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-cta__text {
  max-width: 60ch;
  margin: 0 0 22px;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(18, 17, 15, 0.82);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-cta .btn-primary {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--lime);
}

.page-about .about-cta .btn-primary:hover,
.page-about .about-cta .btn-primary:focus-visible {
  background: var(--moss);
  border-color: var(--moss);
  color: var(--paper);
}

.page-about .about-cta .btn-ghost {
  background: transparent;
  border-color: rgba(18, 17, 15, 0.4);
  color: var(--ink);
}

.page-about .about-cta .btn-ghost:hover,
.page-about .about-cta .btn-ghost:focus-visible {
  border-color: var(--ink);
  background: rgba(18, 17, 15, 0.08);
  color: var(--ink);
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero {
    padding: 34px 30px 36px;
  }

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

  .page-about .tab-label {
    font-size: 14px;
    padding: 15px 12px;
  }

  .page-about .tab-sub {
    font-size: 11px;
  }

  .page-about .shift-panel {
    padding: 24px 22px 26px;
  }

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

  .page-about .calib-step {
    border-left-width: 1px;
    border-top: 2px solid var(--clay);
  }

  .page-about .calib-step + .calib-step {
    border-left: 0;
  }

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

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

  .page-about .about-cta {
    padding: 40px 36px 44px;
  }
}

@media (min-width: 900px) {
  .page-about {
    --about-rail-w: 118px;
  }

  .page-about .about-hero {
    margin: 14px 0 72px;
    padding: 44px 44px 46px;
  }

  .page-about .chapter {
    display: grid;
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    column-gap: 44px;
    margin-bottom: 78px;
    padding-top: 26px;
  }

  .page-about .chapter-rail {
    grid-column: 1;
    position: sticky;
    top: var(--about-sticky-top);
    align-self: start;
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
    margin-bottom: 0;
  }

  .page-about .chapter-rail::before {
    content: "";
    width: 1px;
    height: 42px;
    background: linear-gradient(180deg, var(--lime), rgba(198, 255, 61, 0));
  }

  .page-about .chapter-num {
    font-size: 38px;
  }

  .page-about .chapter-note {
    writing-mode: vertical-rl;
    letter-spacing: 0.3em;
  }

  .page-about .chapter-body {
    grid-column: 2;
    min-width: 0;
  }

  .page-about .tl-text,
  .page-about .tl-note {
    max-width: 66ch;
  }

  .page-about .about-figure {
    margin: 30px 0 30px;
  }

  .page-about .about-figure .mlabel {
    position: absolute;
    right: 12px;
    bottom: 10px;
  }
}

@media (min-width: 1100px) {
  .page-about {
    --about-rail-w: 148px;
  }

  .page-about .chapter {
    column-gap: 56px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .shift-panel {
    animation: none;
  }

  .page-about .tl-item::before,
  .page-about .tl-note,
  .page-about .chapter-num {
    transition: none;
  }
}