.page-about {
  --about-line: var(--grid);
  --about-card-bg: var(--night);
}

/* ---------- 首屏 ---------- */
.page-about .brand-hero {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
  padding: clamp(34px, 6vw, 84px) 0 clamp(44px, 7vw, 104px);
  border-bottom: 1px solid var(--about-line);
}

.page-about .brand-hero__stamp {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-family: var(--font-mono);
}

.page-about .brand-hero__stamp-num {
  font-size: 1.5rem;
  letter-spacing: .06em;
  color: var(--amber);
}

.page-about .brand-hero__stamp-name {
  font-size: .76rem;
  letter-spacing: .18em;
  color: var(--haze);
}

.page-about .brand-hero__kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .22em;
  color: var(--blue);
}

.page-about .brand-hero h1 {
  margin: 0 0 18px;
  font-size: clamp(1.9rem, 4vw, 3.1rem);
  line-height: 1.24;
  letter-spacing: -.01em;
  color: var(--star);
  max-width: 20ch;
}

.page-about .brand-hero__lead {
  margin: 0;
  max-width: 42ch;
  color: var(--haze);
  font-size: 1rem;
  line-height: 1.82;
}

.page-about .brand-hero__metrics {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .brand-hero__metrics li {
  background: var(--night);
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.page-about .brand-hero__metric-num {
  font-family: var(--font-mono);
  font-size: 1.12rem;
  color: var(--mint);
  letter-spacing: .02em;
}

.page-about .brand-hero__metric-label {
  font-size: .74rem;
  letter-spacing: .1em;
  color: var(--haze);
}

/* ---------- 章节通用 ---------- */
.page-about .chapter {
  padding-top: clamp(56px, 9vw, 128px);
}

.page-about .chapter__head {
  max-width: 60ch;
}

.page-about .section-title {
  display: flex;
  align-items: baseline;
  gap: 14px;
  flex-wrap: wrap;
  margin: 0;
  font-size: clamp(1.36rem, 2.4vw, 1.94rem);
  line-height: 1.3;
  color: var(--star);
}

.page-about .section-title__code {
  flex: none;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .14em;
  color: var(--amber);
  border: 1px solid rgba(255, 194, 74, .38);
  padding: 4px 9px;
}

.page-about .chapter__note {
  margin: 14px 0 0;
  color: var(--haze);
  font-size: .95rem;
  line-height: 1.78;
}

.page-about .chapter__figure {
  margin-top: clamp(26px, 4vw, 44px);
}

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  list-style: none;
  margin: clamp(32px, 5vw, 52px) 0 0;
  padding: 0 0 0 30px;
  position: relative;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: linear-gradient(180deg, var(--amber), var(--blue) 48%, var(--mint));
  opacity: .72;
}

.page-about .timeline__item {
  position: relative;
  padding-bottom: 30px;
}

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

.page-about .timeline__node {
  position: absolute;
  left: -30px;
  top: 8px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 0 3px rgba(255, 194, 74, .14);
  transition: background .25s var(--ease), box-shadow .25s var(--ease);
}

.page-about .timeline__item--now .timeline__node {
  background: var(--mint);
  box-shadow: 0 0 0 4px rgba(47, 232, 176, .18), 0 0 13px rgba(47, 232, 176, .55);
}

.page-about .timeline__card {
  padding: 2px 0 2px 14px;
  border-left: 1px solid transparent;
  transition: border-color .25s var(--ease);
}

.page-about .timeline__item:hover .timeline__card,
.page-about .timeline__item:focus-within .timeline__card {
  border-left-color: var(--blue);
}

.page-about .timeline__code {
  font-family: var(--font-mono);
  font-size: .73rem;
  letter-spacing: .12em;
  color: var(--haze);
}

.page-about .timeline__title {
  margin: 7px 0 7px;
  font-size: 1.02rem;
  color: var(--star);
  letter-spacing: .01em;
}

.page-about .timeline__text {
  margin: 0;
  max-width: 48ch;
  color: var(--haze);
  font-size: .93rem;
  line-height: 1.76;
}

.page-about .timeline__tip {
  display: block;
  margin-top: 9px;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .06em;
  color: var(--mint);
  opacity: 0;
  transform: translateY(-4px);
  transition: opacity .25s var(--ease), transform .25s var(--ease);
}

.page-about .timeline__item:hover .timeline__tip,
.page-about .timeline__item:focus-within .timeline__tip {
  opacity: 1;
  transform: none;
}

/* ---------- 体系视图切换 ---------- */
.page-about .system-view {
  margin-top: clamp(26px, 4vw, 40px);
}

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

.page-about .system-view__tabs {
  display: inline-flex;
  border: 1px solid var(--about-line);
  margin-bottom: 26px;
}

.page-about .system-view__tab {
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .08em;
  padding: 10px 20px;
  color: var(--haze);
  cursor: pointer;
  border-right: 1px solid var(--about-line);
  transition: color .2s var(--ease), background .2s var(--ease);
}

.page-about .system-view__tab:last-child {
  border-right: 0;
}

.page-about .system-view__tab:hover {
  color: var(--star);
}

.page-about #about-view-nine:checked ~ .system-view__tabs .system-view__tab[for="about-view-nine"],
.page-about #about-view-twelve:checked ~ .system-view__tabs .system-view__tab[for="about-view-twelve"] {
  color: var(--deep);
  background: var(--mint);
}

.page-about .system-view__panel {
  display: none;
}

.page-about #about-view-nine:checked ~ .system-view__panel--nine,
.page-about #about-view-twelve:checked ~ .system-view__panel--twelve {
  display: block;
}

.page-about .system-view__figure {
  margin: 0 0 28px;
}

.page-about .system-view__lead {
  margin: 0;
  max-width: 52ch;
  color: var(--haze);
  font-size: .96rem;
  line-height: 1.8;
}

.page-about .system-view__foot {
  margin: 26px 0 0;
}

/* ---------- 栏目卡片 ---------- */
.page-about .channel-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .channel-card {
  background: var(--about-card-bg);
  padding: 22px 20px 20px;
  display: flex;
  flex-direction: column;
  gap: 9px;
  border-left: 2px solid transparent;
  transition: border-color .25s var(--ease), background .25s var(--ease);
}

.page-about .channel-card:hover,
.page-about .channel-card:focus-within {
  border-left-color: var(--mint);
  background: #241748;
}

.page-about .channel-card__name {
  margin: 0;
  font-size: 1rem;
  color: var(--star);
  letter-spacing: .01em;
}

.page-about .channel-card__text {
  margin: 0;
  font-size: .89rem;
  line-height: 1.72;
  color: var(--haze);
}

.page-about .channel-card__link {
  margin-top: auto;
  align-self: flex-start;
  font-family: var(--font-mono);
  font-size: .73rem;
  letter-spacing: .09em;
  color: var(--blue);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .channel-card__link:hover {
  color: var(--mint);
  border-bottom-color: var(--mint);
}

/* ---------- 十二分区 ---------- */
.page-about .zone-grid {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .zone-cell {
  background: var(--deep);
  aspect-ratio: 1 / 1;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 1.08rem;
  letter-spacing: .04em;
  color: var(--blue);
  transition: background .2s var(--ease), color .2s var(--ease);
}

.page-about .zone-cell:hover {
  background: rgba(47, 232, 176, .1);
  color: var(--mint);
}

/* ---------- 入口调整 ---------- */
.page-about .shift-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .shift-grid__main,
.page-about .shift-grid__side {
  padding: clamp(22px, 3.4vw, 38px);
}

.page-about .shift-grid__main {
  background: var(--deep);
}

.page-about .shift-grid__side {
  background: var(--night);
}

.page-about .shift-grid__title {
  margin: 0 0 16px;
  font-size: 1.06rem;
  color: var(--star);
}

.page-about .shift-grid__subtitle {
  margin: 0 0 14px;
  font-size: .98rem;
  color: var(--mint);
  letter-spacing: .01em;
}

.page-about .shift-grid__text {
  margin: 0 0 14px;
  max-width: 46ch;
  color: var(--haze);
  font-size: .93rem;
  line-height: 1.8;
}

.page-about .shift-grid__text:last-of-type {
  margin-bottom: 0;
}

.page-about .shift-grid__text strong {
  color: var(--star);
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: .92em;
}

.page-about .shift-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 12px;
}

.page-about .shift-list li {
  position: relative;
  padding-left: 20px;
  color: var(--haze);
  font-size: .91rem;
  line-height: 1.76;
}

.page-about .shift-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .68em;
  width: 8px;
  height: 1px;
  background: var(--blue);
}

.page-about .shift-grid__actions {
  margin: 24px 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 复核 ---------- */
.page-about .review-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .review-grid__figure {
  margin: 0;
}

.page-about .review-grid__text {
  margin: 0;
  max-width: 52ch;
  color: var(--haze);
  font-size: .95rem;
  line-height: 1.84;
}

.page-about .review-steps {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .review-step {
  background: var(--night);
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  padding: 16px 18px;
  transition: background .22s var(--ease);
}

.page-about .review-step:hover {
  background: #241748;
}

.page-about .review-step__num {
  font-family: var(--font-mono);
  font-size: .82rem;
  letter-spacing: .1em;
  color: var(--orange);
}

.page-about .review-step__text {
  margin: 0;
  color: var(--haze);
  font-size: .92rem;
  line-height: 1.76;
}

.page-about .review-grid__note {
  margin: 24px 0 0;
  padding-left: 16px;
  border-left: 2px solid var(--mint);
  color: var(--haze);
  font-size: .92rem;
  line-height: 1.8;
  max-width: 52ch;
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .team-card {
  background: var(--about-card-bg);
  padding: clamp(22px, 3vw, 30px);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.page-about .team-card--accent {
  background: linear-gradient(180deg, rgba(47, 232, 176, .08), transparent 60%), var(--night);
}

.page-about .team-card__tag {
  align-self: flex-start;
  font-family: var(--font-mono);
  font-size: .71rem;
  letter-spacing: .12em;
  color: var(--amber);
  border: 1px solid rgba(255, 194, 74, .36);
  padding: 3px 9px;
}

.page-about .team-card__title {
  margin: 0;
  font-size: 1.02rem;
  line-height: 1.5;
  color: var(--star);
}

.page-about .team-card__text {
  margin: 0;
  color: var(--haze);
  font-size: .91rem;
  line-height: 1.78;
}

/* ---------- 合作与引用 ---------- */
.page-about .coop-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .coop-grid__text {
  margin: 0 0 16px;
  max-width: 54ch;
  color: var(--haze);
  font-size: .94rem;
  line-height: 1.84;
}

.page-about .coop-grid__text:last-child {
  margin-bottom: 0;
}

.page-about .coop-wall {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-content: flex-start;
}

.page-about .coop-tag {
  font-family: var(--font-mono);
  font-size: .73rem;
  letter-spacing: .08em;
  padding: 9px 14px;
  color: var(--haze);
  background: var(--glass);
  border: 1px solid var(--about-line);
  transition: border-color .2s var(--ease), color .2s var(--ease);
}

.page-about .coop-tag:hover {
  border-color: var(--blue);
  color: var(--star);
}

/* ---------- CTA ---------- */
.page-about .chapter--cta {
  padding-bottom: clamp(40px, 7vw, 96px);
}

.page-about .cta-panel {
  border: 1px solid var(--about-line);
  background:
    linear-gradient(135deg, rgba(59, 107, 255, .16), transparent 58%),
    var(--night);
  padding: clamp(28px, 5vw, 54px);
  display: grid;
  gap: 16px;
}

.page-about .cta-panel__title {
  margin: 0;
  font-size: clamp(1.2rem, 2.2vw, 1.7rem);
  line-height: 1.4;
  color: var(--star);
}

.page-about .cta-panel__text {
  margin: 0;
  max-width: 56ch;
  color: var(--haze);
  font-size: .94rem;
  line-height: 1.84;
}

.page-about .cta-panel__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 6px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .zone-grid {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

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

@media (min-width: 900px) {
  .page-about .brand-hero {
    grid-template-columns: 110px minmax(0, 1fr) 250px;
    gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .brand-hero__stamp {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
  }

  .page-about .brand-hero__stamp-num {
    font-size: 2rem;
  }

  .page-about .brand-hero__stamp-name {
    writing-mode: vertical-rl;
    letter-spacing: .3em;
  }

  .page-about .shift-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }

  .page-about .review-grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: clamp(28px, 4vw, 52px);
    align-items: start;
  }

  .page-about .coop-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: clamp(28px, 4vw, 56px);
  }
}

@media (hover: none) {
  .page-about .timeline__tip {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .timeline__node,
  .page-about .timeline__card,
  .page-about .timeline__tip,
  .page-about .channel-card,
  .page-about .channel-card__link,
  .page-about .zone-cell,
  .page-about .coop-tag,
  .page-about .review-step,
  .page-about .system-view__tab {
    transition: none;
  }
}