.page-about {
  --about-rail-w: 224px;
  --about-sticky-top: 6.5rem;
  background: var(--ink-900);
  color: var(--body-tint);
  padding-block: clamp(1.5rem, 4vw, 2.75rem) clamp(3rem, 7vw, 5rem);
}

.page-about .breadcrumb {
  margin-bottom: clamp(1.25rem, 3vw, 2.25rem);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  max-width: 940px;
}

.page-about .about-hero .eyebrow {
  color: var(--red);
}

.page-about .about-hero__title {
  color: var(--white);
  margin: 0.7rem 0 0;
  max-width: 20ch;
  line-height: 1.08;
}

.page-about .about-hero__lede {
  font-family: var(--font-serif);
  font-size: clamp(1.02rem, 1.6vw, 1.26rem);
  line-height: 1.95;
  color: var(--paper);
  letter-spacing: 0.01em;
  margin: clamp(1rem, 2.4vw, 1.6rem) 0 0;
  max-width: 32em;
}

.page-about .hero-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem 2rem;
  list-style: none;
  margin: clamp(1.5rem, 3vw, 2.25rem) 0 0;
  padding: 1.15rem 0 0;
  border-top: 1px solid var(--line);
}

.page-about .hero-facts li {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  font-size: 0.82rem;
  color: var(--steel);
  letter-spacing: 0.04em;
}

.page-about .hero-facts b {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--cyan);
  letter-spacing: 0.02em;
}

/* ---------- 双栏骨架 ---------- */
.page-about .about-layout {
  display: grid;
  gap: clamp(1.75rem, 4vw, 3rem);
  margin-top: clamp(2rem, 5vw, 3.25rem);
}

.page-about .about-rail__inner {
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--ink-800);
  padding: 0.95rem 0.95rem 1.05rem;
}

.page-about .about-rail__title {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--steel);
  margin: 0 0 0.7rem;
}

.page-about .about-rail__list {
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  list-style: none;
  margin: 0;
  padding: 0 0.15rem 0.15rem;
  scrollbar-width: thin;
}

.page-about .rail-tick {
  display: flex;
  flex-direction: column;
  gap: 0.18rem;
  min-width: 116px;
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  text-decoration: none;
  transition: border-color 0.16s var(--ease), background-color 0.16s var(--ease);
}

.page-about .rail-tick:hover,
.page-about .rail-tick:focus-visible {
  border-color: var(--red);
  background: var(--ink-900);
}

.page-about .rail-tick:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .rail-tick__meta {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--cyan);
  letter-spacing: 0.04em;
}

.page-about .rail-tick__label {
  font-size: 0.84rem;
  color: var(--paper);
  white-space: nowrap;
}

/* ---------- 章节 ---------- */
.page-about .about-flow {
  min-width: 0;
  max-width: 760px;
}

.page-about .about-chapter {
  padding-block: clamp(2rem, 5vw, 3.5rem);
  border-top: 1px solid var(--line);
  scroll-margin-top: 6rem;
}

.page-about .about-chapter:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .chapter-head {
  margin-bottom: clamp(1.15rem, 2.6vw, 1.85rem);
}

.page-about .chapter-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
  margin: 0;
}

.page-about .chapter-title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(1.55rem, 3.4vw, 2.35rem);
  line-height: 1.32;
  letter-spacing: 0.005em;
  color: var(--white);
  margin: 0.55rem 0 0;
}

.page-about .chapter-rule {
  display: block;
  width: 56px;
  height: 3px;
  background: var(--red);
  margin-top: 1rem;
}

.page-about .prose {
  max-width: 40em;
}

.page-about .prose p {
  font-size: 1.0625rem;
  line-height: 1.9;
  letter-spacing: 0.01em;
  color: var(--body-tint);
  margin: 0 0 1.15rem;
}

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

.page-about .chapter-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-top: clamp(1.4rem, 3vw, 2rem);
}

/* ---------- 数字面板 ---------- */
.page-about .figure-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
  margin-top: clamp(1.5rem, 3.2vw, 2.25rem);
}

.page-about .figure-cell {
  background: var(--ink-800);
  padding: 1.1rem 1.15rem 1.2rem;
}

.page-about .figure-num {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: clamp(1.55rem, 4vw, 2.1rem);
  line-height: 1;
  color: var(--white);
  margin: 0;
  letter-spacing: 0.01em;
}

.page-about .figure-num small {
  font-size: 0.46em;
  color: var(--steel);
  margin-left: 0.28em;
  letter-spacing: 0.04em;
}

.page-about .figure-num--red {
  color: var(--red);
}

.page-about .figure-num--cyan {
  color: var(--cyan);
}

.page-about .figure-label {
  font-size: 0.82rem;
  line-height: 1.6;
  color: var(--steel);
  margin: 0.5rem 0 0;
  letter-spacing: 0.04em;
}

/* ---------- 时间轴 ---------- */
.page-about .timeline {
  list-style: none;
  position: relative;
  margin: clamp(1.5rem, 3.4vw, 2.4rem) 0 0;
  padding: 0 0 0 1.75rem;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 0.35rem;
  top: 0.55rem;
  bottom: 0.55rem;
  width: 2px;
  background: var(--line-strong);
}

.page-about .timeline__item {
  position: relative;
  padding-bottom: clamp(1.4rem, 3vw, 2rem);
}

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

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: calc(-1.4rem - 4px);
  top: 0.42rem;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 2px solid var(--red);
  box-sizing: border-box;
}

.page-about .timeline__stamp {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--red);
  margin: 0;
  text-transform: uppercase;
}

.page-about .timeline__title {
  font-size: 1.06rem;
  font-weight: 700;
  line-height: 1.6;
  color: var(--white);
  margin: 0.42rem 0 0.45rem;
}

.page-about .timeline__text {
  font-size: 0.94rem;
  line-height: 1.85;
  color: var(--body-tint);
  margin: 0;
  max-width: 38em;
}

/* ---------- 图位 ---------- */
.page-about .about-figure {
  margin: clamp(1.4rem, 3vw, 2.1rem) 0;
}

.page-about .media-frame {
  background: var(--ink-800);
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .media-frame__caption {
  font-size: 0.78rem;
  line-height: 1.7;
  color: var(--steel);
  letter-spacing: 0.03em;
  margin: 0.65rem 0 0;
}

.page-about .timeline .media-frame {
  margin: 0.2rem 0 0;
}

/* ---------- 团队图表 ---------- */
.page-about .team-chart {
  margin-top: clamp(1.5rem, 3.4vw, 2.25rem);
}

.page-about .team-bar {
  display: flex;
  height: 58px;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  background: var(--ink-800);
}

.page-about .team-bar__seg {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: filter 0.16s var(--ease);
}

.page-about .team-bar__seg:first-child {
  border-radius: calc(var(--r-sm) - 1px) 0 0 calc(var(--r-sm) - 1px);
}

.page-about .team-bar__seg:last-child {
  border-radius: 0 calc(var(--r-sm) - 1px) calc(var(--r-sm) - 1px) 0;
}

.page-about .team-bar__seg:hover,
.page-about .team-bar__seg:focus-visible {
  filter: brightness(1.28);
  outline: none;
}

.page-about .team-bar__seg:focus-visible {
  box-shadow: inset 0 0 0 2px var(--cyan);
}

.page-about .team-bar__seg--edit {
  width: 25.6%;
  background: var(--red);
}

.page-about .team-bar__seg--night {
  width: 20.9%;
  background: var(--cyan);
}

.page-about .team-bar__seg--field {
  width: 36.1%;
  background: var(--line-strong);
}

.page-about .team-bar__seg--ops {
  width: 17.4%;
  background: var(--line);
}

.page-about .team-bar__num {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--white);
}

.page-about .team-bar__seg--night .team-bar__num,
.page-about .team-bar__seg--ops .team-bar__num {
  color: var(--ink-900);
}

.page-about .team-bar__seg::after {
  content: attr(data-post);
  position: absolute;
  bottom: calc(100% + 9px);
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  background: var(--ink-900);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-xs);
  color: var(--paper);
  font-size: 0.76rem;
  letter-spacing: 0.03em;
  padding: 0.35rem 0.6rem;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.16s var(--ease), transform 0.16s var(--ease);
  z-index: 3;
}

.page-about .team-bar__seg:hover::after,
.page-about .team-bar__seg:focus-visible::after {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.page-about .team-legend {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.7rem 1.25rem;
  list-style: none;
  margin: 1rem 0 0;
  padding: 0;
}

.page-about .team-legend li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.86rem;
  color: var(--steel);
}

.page-about .team-legend b {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--paper);
}

.page-about .team-swatch {
  width: 10px;
  height: 10px;
  border-radius: 2px;
  flex: none;
}

.page-about .team-swatch--edit {
  background: var(--red);
}

.page-about .team-swatch--night {
  background: var(--cyan);
}

.page-about .team-swatch--field {
  background: var(--line-strong);
}

.page-about .team-swatch--ops {
  background: var(--line);
}

/* ---------- 流程 ---------- */
.page-about .flow-steps {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
  margin: clamp(1.5rem, 3.4vw, 2.25rem) 0 0;
  padding: 0;
}

.page-about .flow-step {
  background: var(--ink-800);
  padding: 1.15rem 1.1rem 1.3rem;
}

.page-about .flow-step__no {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  letter-spacing: 0.16em;
  color: var(--cyan);
  margin: 0;
}

.page-about .flow-step__title {
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--white);
  margin: 0.5rem 0 0.45rem;
}

.page-about .flow-step__text {
  font-size: 0.88rem;
  line-height: 1.8;
  color: var(--body-tint);
  margin: 0;
}

/* ---------- 合作生态 ---------- */
.page-about .eco {
  display: grid;
  gap: clamp(1.25rem, 3vw, 2rem);
  margin-top: clamp(1.5rem, 3.4vw, 2.25rem);
}

.page-about .eco-dots {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(13px, 1fr));
  gap: 6px;
  margin: 0;
  padding: 0;
  max-width: 340px;
}

.page-about .eco-dot {
  aspect-ratio: 1 / 1;
  border-radius: 50%;
}

.page-about .eco-dot--club {
  background: var(--red);
}

.page-about .eco-dot--host {
  background: var(--cyan);
}

.page-about .eco-dot--org {
  background: var(--line-strong);
}

.page-about .eco-legend {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.6rem;
}

.page-about .eco-legend li {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.9rem;
  color: var(--body-tint);
}

.page-about .eco-legend b {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 500;
  color: var(--white);
}

.page-about .eco-swatch {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  flex: none;
}

.page-about .eco-swatch--club {
  background: var(--red);
}

.page-about .eco-swatch--host {
  background: var(--cyan);
}

.page-about .eco-swatch--org {
  background: var(--line-strong);
}

/* ---------- 服务网络 ---------- */
.page-about .figure-grid--three {
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
}

.page-about .cred-list {
  list-style: none;
  margin: clamp(1.5rem, 3.2vw, 2.1rem) 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .cred-list li {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1.25rem;
  align-items: baseline;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--line);
}

.page-about .cred-key {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  color: var(--steel);
  min-width: 76px;
}

.page-about .cred-val {
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--paper);
}

/* ---------- 回顶刻度 ---------- */
.page-about .about-toplink {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  margin-top: clamp(2rem, 5vw, 3.25rem);
  padding: 0.55rem 0.95rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--r-pill);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  letter-spacing: 0.1em;
  color: var(--cyan);
  text-decoration: none;
  transition: border-color 0.16s var(--ease), color 0.16s var(--ease);
}

.page-about .about-toplink:hover,
.page-about .about-toplink:focus-visible {
  border-color: var(--red);
  color: var(--paper);
}

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

/* ---------- 平板及以上 ---------- */
@media (min-width: 1024px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(2rem, 4.5vw, 4rem);
  }

  .page-about .about-rail__inner {
    position: sticky;
    top: var(--about-sticky-top);
    padding: 1.1rem 1.05rem 1.2rem;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 0.45rem;
    overflow: visible;
  }

  .page-about .rail-tick {
    min-width: 0;
    width: 100%;
    padding: 0.6rem 0.75rem;
  }

  .page-about .rail-tick__label {
    white-space: normal;
  }

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

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

  .page-about .eco {
    grid-template-columns: minmax(0, 340px) minmax(0, 1fr);
    align-items: center;
  }

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

  .page-about .team-legend li {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.3rem;
  }

  .page-about .team-legend b {
    margin-left: 0;
  }
}

@media (min-width: 1280px) {
  .page-about .about-flow {
    max-width: 780px;
  }
}

/* ---------- 小屏微调 ---------- */
@media (max-width: 560px) {
  .page-about .hero-facts {
    gap: 0.6rem 1.35rem;
  }

  .page-about .team-bar {
    height: 48px;
  }

  .page-about .team-bar__num {
    font-size: 0.72rem;
  }

  .page-about .team-bar__seg::after {
    font-size: 0.7rem;
    white-space: normal;
    max-width: 150px;
    text-align: center;
  }

  .page-about .chapter-links .btn {
    width: 100%;
    justify-content: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .rail-tick,
  .page-about .team-bar__seg,
  .page-about .team-bar__seg::after,
  .page-about .about-toplink {
    transition: none;
  }
}