.page-about {
  --about-line: var(--line);
  background: var(--ink-900);
  color: var(--text);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about .num {
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--green);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(96px, 14vh, 160px) 0 clamp(36px, 5vw, 62px);
  border-bottom: 1px solid var(--about-line);
  background-color: var(--ink-800);
  background-image:
    radial-gradient(circle at 84% 6%, rgba(61, 255, 158, 0.10), transparent 46%),
    radial-gradient(circle at 6% 96%, rgba(53, 215, 255, 0.08), transparent 42%),
    repeating-linear-gradient(to right, rgba(36, 51, 79, 0.5) 0 1px, transparent 1px 88px),
    repeating-linear-gradient(to bottom, rgba(36, 51, 79, 0.4) 0 1px, transparent 1px 88px);
}

.page-about .about-hero h1 {
  margin: 18px 0 0;
  max-width: 20ch;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(32px, 6vw, 60px);
  line-height: 1.08;
  letter-spacing: -0.01em;
}

.page-about .about-hero__lead {
  margin: 22px 0 0;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-hero__board,
.page-about .scale-board {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 32px 0 0;
  border: 1px solid var(--about-line);
  background: var(--about-line);
}

.page-about .about-hero__board .scoreboard__item,
.page-about .scale-board .scoreboard__item {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 5px;
  padding: 16px 18px;
  background: var(--ink-900);
}

.page-about .about-hero__board .scoreboard__value,
.page-about .scale-board .scoreboard__value {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1;
  color: var(--green);
}

.page-about .scale-board .scoreboard__value {
  color: var(--text);
}

.page-about .about-hero__board .scoreboard__unit,
.page-about .scale-board .scoreboard__unit {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--green-dim);
}

.page-about .about-hero__board .scoreboard__label,
.page-about .scale-board .scoreboard__label {
  flex: 1 0 100%;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--muted);
}

/* ---------- 索引轨道 + 正文壳 ---------- */
.page-about .about-shell {
  padding-top: clamp(36px, 5vw, 64px);
  padding-bottom: clamp(48px, 7vw, 92px);
}

.page-about .year-rail {
  display: flex;
  gap: 8px;
  margin: 0 0 26px;
  padding: 0 0 12px;
  overflow-x: auto;
  border-bottom: 1px solid var(--about-line);
  scrollbar-width: thin;
}

.page-about .year-rail__title {
  display: none;
  margin: 0 0 12px;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .year-rail__item {
  flex: 0 0 auto;
  padding: 6px 12px;
  border: 1px solid var(--about-line);
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  text-decoration: none;
  transition: color 180ms ease, border-color 180ms ease;
}

.page-about .year-rail__item:hover,
.page-about .year-rail__item:focus-visible {
  color: var(--green);
  border-color: var(--green-dim);
}

/* ---------- 分节 ---------- */
.page-about .about-block {
  scroll-margin-top: 96px;
  padding: clamp(30px, 5vw, 56px) 0;
}

.page-about .about-block + .about-block {
  border-top: 1px solid var(--about-line);
}

.page-about .about-block__head h2 {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(25px, 3.6vw, 38px);
  line-height: 1.2;
  max-width: 24ch;
}

.page-about .about-block__lede {
  margin: 14px 0 0;
  max-width: 70ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-block__lede .num {
  font-size: 17px;
}

.page-about .about-split {
  display: grid;
  gap: 24px;
  margin-top: 26px;
}

.page-about .prose p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--muted);
}

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

.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--about-line);
  background: var(--ink-800);
}

.page-about .about-figure--wide {
  margin-top: 28px;
}

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

.page-about .about-figure figcaption {
  padding: 10px 14px;
  border-top: 1px solid var(--about-line);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 215, 255, 0.4);
  transition: color 160ms ease, border-color 160ms ease;
}

.page-about .link:hover,
.page-about .link:focus-visible {
  color: var(--green);
  border-bottom-color: var(--green);
}

/* ---------- 版本时间轴 ---------- */
.page-about .epoch-list {
  display: grid;
  gap: 10px;
  margin-top: 26px;
}

.page-about .epoch {
  border: 1px solid var(--about-line);
  background: var(--ink-800);
  transition: border-color 200ms ease, background-color 200ms ease;
}

.page-about .epoch:hover {
  border-color: var(--green-dim);
}

.page-about .epoch[open] {
  border-color: var(--green);
  background: var(--ink-700);
}

.page-about .epoch__summary {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
}

.page-about .epoch__summary::-webkit-details-marker {
  display: none;
}

.page-about .epoch__tag {
  flex: 0 0 auto;
  padding: 3px 9px;
  background: var(--green);
  color: var(--ink-900);
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.06em;
}

.page-about .epoch__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(15px, 2.1vw, 19px);
  line-height: 1.4;
}

.page-about .epoch__hint {
  margin-left: auto;
  flex: 0 0 auto;
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .epoch__hint::after {
  content: "展开";
}

.page-about .epoch[open] .epoch__hint::after {
  content: "收起";
}

.page-about .epoch__body {
  display: grid;
  gap: 18px;
  padding: 18px;
  border-top: 1px solid var(--about-line);
}

.page-about .epoch__col h3 {
  margin: 0 0 8px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .epoch__col p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .epoch__col[open] p {
  color: var(--text);
}

/* ---------- 团队分工 ---------- */
.page-about .role-grid {
  display: grid;
  gap: 14px;
  margin-top: 28px;
}

.page-about .role-card {
  position: relative;
  padding: 20px 20px 22px;
  border: 1px solid var(--about-line);
  background: var(--ink-800);
  overflow: hidden;
  transition: border-color 200ms ease;
}

.page-about .role-card::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 3px;
  background: var(--cyan);
}

.page-about .role-card--data::before {
  background: var(--green);
}

.page-about .role-card--service::before {
  background: var(--orange);
}

.page-about .role-card:hover,
.page-about .role-card:focus-within {
  border-color: var(--green);
}

.page-about .role-card__tag {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .role-card h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 19px;
  line-height: 1.35;
}

.page-about .role-card__base,
.page-about .role-card__more {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .role-card__more {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--about-line);
  color: var(--text);
}

/* ---------- 合作生态 ---------- */
.page-about .eco-split {
  display: grid;
  gap: 24px;
  margin-top: 26px;
}

.page-about .eco-panel {
  border: 1px solid var(--about-line);
  background: var(--ink-800);
  padding: 16px;
}

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

.page-about .eco-map .eco-line {
  stroke: var(--line);
  stroke-width: 1;
  fill: none;
}

.page-about .eco-map .eco-ring {
  fill: none;
  stroke: var(--green-dim);
  stroke-width: 1;
  stroke-dasharray: 4 6;
}

.page-about .eco-map .eco-hub {
  fill: var(--green);
}

.page-about .eco-map .eco-node {
  fill: var(--ink-700);
  stroke: var(--cyan);
  stroke-width: 1;
}

.page-about .eco-panel__note {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 使用规模与场景 ---------- */
.page-about .scale-board {
  margin-top: 26px;
}

.page-about .scene-list {
  display: grid;
  gap: 12px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .scene-list li {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: 12px;
  padding: 16px;
  border: 1px solid var(--about-line);
  background: var(--ink-800);
  transition: border-color 200ms ease;
}

.page-about .scene-list li:hover {
  border-color: var(--green-dim);
}

.page-about .scene-list__idx {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--green);
  padding-top: 3px;
}

.page-about .scene-list h3 {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
}

.page-about .scene-list p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 长期使用 ---------- */
.page-about .stay-list {
  display: grid;
  gap: 12px;
  margin-top: 26px;
}

.page-about .stay-item {
  display: grid;
  gap: 8px;
  padding: 20px;
  border: 1px solid var(--about-line);
  background: linear-gradient(90deg, rgba(22, 35, 63, 0.92), rgba(16, 27, 51, 0.5));
}

.page-about .stay-item__k {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--green);
}

.page-about .stay-item__v {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 结尾引导 ---------- */
.page-about .about-cta {
  border-top: 1px solid var(--about-line);
  background-color: var(--ink-800);
  background-image: radial-gradient(circle at 14% 118%, rgba(255, 138, 61, 0.14), transparent 52%);
}

.page-about .about-cta__inner {
  display: grid;
  gap: 26px;
  padding-top: clamp(40px, 6vw, 72px);
  padding-bottom: clamp(40px, 6vw, 72px);
}

.page-about .about-cta h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 3.2vw, 34px);
  line-height: 1.22;
  max-width: 22ch;
}

.page-about .about-cta__copy p {
  margin: 14px 0 0;
  max-width: 58ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 交互增强 ---------- */
@media (hover: hover) {
  .page-about .role-card__more {
    max-height: 0;
    margin-top: 0;
    padding-top: 0;
    border-top-color: transparent;
    opacity: 0;
    overflow: hidden;
    transition: opacity 220ms ease, max-height 260ms ease, margin-top 220ms ease, padding-top 220ms ease;
  }

  .page-about .role-card:hover .role-card__more,
  .page-about .role-card:focus-within .role-card__more {
    max-height: 260px;
    margin-top: 12px;
    padding-top: 12px;
    border-top-color: var(--about-line);
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .epoch,
  .page-about .role-card,
  .page-about .scene-list li,
  .page-about .year-rail__item {
    transition: none;
  }
}

/* ---------- 窄屏到宽屏 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero__board,
  .page-about .scale-board {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 780px) {
  .page-about .epoch__body {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 28px;
  }

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

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

  .page-about .stay-item {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: 22px;
    align-items: baseline;
  }
}

@media (min-width: 900px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .eco-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 32px;
    align-items: stretch;
  }

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.9fr);
    gap: 48px;
    align-items: center;
  }
}

@media (min-width: 1040px) {
  .page-about .about-shell {
    display: grid;
    grid-template-columns: 132px minmax(0, 1fr);
    gap: clamp(32px, 4vw, 64px);
    align-items: start;
  }

  .page-about .year-rail {
    display: block;
    position: sticky;
    top: 104px;
    align-self: start;
    overflow: visible;
    margin: 0;
    padding: 0 0 0 16px;
    border-bottom: 0;
    border-left: 1px solid var(--about-line);
  }

  .page-about .year-rail__title {
    display: block;
  }

  .page-about .year-rail__item {
    display: block;
    position: relative;
    padding: 7px 0 7px 14px;
    border: 0;
    font-size: 13px;
  }

  .page-about .year-rail__item::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    width: 8px;
    height: 1px;
    background: var(--about-line);
    transition: background-color 180ms ease, width 180ms ease;
  }

  .page-about .year-rail__item:hover,
  .page-about .year-rail__item:focus-visible {
    color: var(--green);
  }

  .page-about .year-rail__item:hover::before,
  .page-about .year-rail__item:focus-visible::before {
    background: var(--green);
    width: 16px;
  }

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