.page-about {
  display: block;
  --about-node: 11px;
  --about-axis-x: 5px;
}

/* ============ 首屏 ============ */
.page-about .about-hero {
  display: grid;
  gap: clamp(22px, 3vw, 42px);
  padding: clamp(18px, 2.6vw, 34px) 0 clamp(28px, 4vw, 54px);
}

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

.page-about .about-hero__media .figure__frame {
  aspect-ratio: 4 / 5;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 3px;
  background: var(--bg-deep);
}

.page-about .about-hero__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  filter: saturate(.86) contrast(1.04);
}

.page-about .about-hero__body {
  max-width: 68ch;
}

.page-about .about-hero__body h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.85rem, 5.4vw, 3.15rem);
  line-height: 1.06;
  letter-spacing: .01em;
  color: var(--ink);
  margin: .35em 0 .5em;
}

.page-about .about-hero__body .lede {
  margin: 0 0 clamp(20px, 2.4vw, 28px);
}

.page-about .about-hero__note {
  margin: clamp(16px, 2vw, 22px) 0 0;
  font-size: .86rem;
  line-height: 1.75;
  color: var(--ink-mute);
}

.page-about .about-hero__note a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(62, 216, 200, .4);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-hero__note a:hover {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

/* 首屏读数 */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  background: var(--line-soft);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-stats__item {
  background: var(--bg);
  padding: 12px 4px 14px 0;
}

.page-about .about-stats__key {
  display: block;
  font-size: .72rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--ink-mute);
  margin-bottom: 4px;
}

.page-about .about-stats__value {
  display: block;
  margin: 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.5rem, 4.2vw, 2rem);
  line-height: 1;
  color: var(--lime);
}

.page-about .about-stats__plus {
  font-size: .62em;
  color: var(--amber);
  margin-left: .12em;
}

/* ============ 时间轴 ============ */
.page-about .about-track {
  border-top: 1px solid var(--line);
  padding-top: clamp(30px, 4vw, 52px);
}

.page-about .timeline {
  position: relative;
  list-style: none;
  margin: clamp(24px, 3vw, 40px) 0 0;
  padding: 0 0 0 30px;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: var(--about-axis-x);
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(180deg,
      var(--lime) 0%,
      var(--amber) 42%,
      var(--magenta) 76%,
      var(--line-strong) 100%);
  opacity: .6;
}

.page-about .tl-item {
  position: relative;
  padding-bottom: clamp(24px, 3vw, 36px);
}

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

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: calc(-30px + var(--about-axis-x) - 5px);
  top: 7px;
  width: var(--about-node);
  height: var(--about-node);
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--steel);
  box-sizing: border-box;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .tl-item:hover::before,
.page-about .tl-item:focus-within::before {
  border-color: var(--lime);
  background: var(--lime);
  transform: scale(1.15);
}

.page-about .tl-item--live::before {
  border-color: var(--amber);
  background: var(--amber);
  box-shadow: 0 0 0 4px rgba(255, 154, 46, .16);
}

.page-about .tl-item__idx {
  display: inline-block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: .76rem;
  letter-spacing: .1em;
  color: var(--amber);
  margin-bottom: 6px;
}

.page-about .tl-item--live .tl-item__idx {
  color: var(--lime);
}

.page-about .tl-item__body h3 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.05rem, 2.6vw, 1.3rem);
  line-height: 1.25;
  color: var(--ink);
  margin: 0 0 .45em;
}

.page-about .tl-item__body p {
  margin: 0;
  font-size: .95rem;
  line-height: 1.8;
  color: var(--ink-soft);
  opacity: .8;
  transform: translateX(0);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .tl-item:hover .tl-item__body p,
.page-about .tl-item:focus-within .tl-item__body p {
  opacity: 1;
  transform: translateX(6px);
}

/* ============ 数据来源 ============ */
.page-about .about-source {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: clamp(30px, 4vw, 54px) 0;
}

.page-about .about-source__copy h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.4rem, 3.8vw, 2rem);
  line-height: 1.14;
  color: var(--ink);
  margin: .3em 0 .6em;
}

.page-about .about-source__copy p {
  margin: 0 0 1.1em;
  font-size: .97rem;
  line-height: 1.85;
  color: var(--ink-soft);
}

.page-about .source-list {
  list-style: none;
  margin: clamp(20px, 2.6vw, 28px) 0 0;
  padding: 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .source-list__item {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .source-list__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.35rem;
  line-height: 1;
  color: var(--lime);
  min-width: 4.6em;
}

.page-about .source-list__unit {
  font-size: .58em;
  color: var(--ink-mute);
  margin-left: .35em;
  letter-spacing: .04em;
}

.page-about .source-list__text {
  flex: 1 1 12ch;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--ink-soft);
}

.page-about .about-source__figure {
  margin: clamp(26px, 3.4vw, 36px) 0 0;
}

.page-about .about-source__figure .figure__frame {
  aspect-ratio: 3 / 2;
  overflow: hidden;
  border: 1px solid var(--line);
  border-left: 3px solid var(--amber);
  background: var(--bg-deep);
}

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

/* ============ 团队 ============ */
.page-about .about-team {
  padding: clamp(32px, 4.4vw, 58px) 0 0;
}

.page-about .team-grid {
  display: grid;
  gap: clamp(16px, 2.2vw, 24px);
  margin-top: clamp(22px, 3vw, 34px);
}

.page-about .team-card {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 3px;
  padding: clamp(20px, 2.6vw, 28px) clamp(18px, 2.4vw, 26px);
  overflow: hidden;
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .team-card::after {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 3px;
  background: var(--steel);
  transition: background var(--dur) var(--ease);
}

.page-about .team-card--lime::after { background: var(--lime); }
.page-about .team-card--amber::after { background: var(--amber); }
.page-about .team-card--cyan::after { background: var(--cyan); }

.page-about .team-card:hover,
.page-about .team-card:focus-visible {
  transform: translate(-3px, -3px);
  border-color: var(--line-strong);
  outline: none;
}

.page-about .team-card__tag {
  display: inline-block;
  font-size: .68rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--bg);
  background: var(--steel);
  padding: 3px 9px;
  margin: 0 0 14px;
}

.page-about .team-card--lime .team-card__tag { background: var(--lime); }
.page-about .team-card--amber .team-card__tag { background: var(--amber); }
.page-about .team-card--cyan .team-card__tag { background: var(--cyan); }

.page-about .team-card h3 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.08rem;
  line-height: 1.3;
  color: var(--ink);
  margin: 0 0 10px;
}

.page-about .team-card__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 2.6rem;
  line-height: 1;
  color: var(--lime);
  margin: 0 0 12px;
}

.page-about .team-card--amber .team-card__num { color: var(--amber); }
.page-about .team-card--cyan .team-card__num { color: var(--cyan); }

.page-about .team-card__desc {
  margin: 0;
  font-size: .9rem;
  line-height: 1.78;
  color: var(--ink-soft);
}

/* ============ 战术板分隔 ============ */
.page-about .about-divider {
  margin: clamp(34px, 4.4vw, 56px) 0 0;
}

.page-about .about-divider .figure__frame {
  aspect-ratio: 16 / 7;
  overflow: hidden;
  background: var(--bg-deep);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .about-divider img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  opacity: .82;
}

/* ============ 合作生态与年鉴 ============ */
.page-about .about-eco {
  padding: clamp(32px, 4.4vw, 58px) 0 0;
}

.page-about .eco-grid {
  display: grid;
  gap: clamp(20px, 2.8vw, 32px);
  margin-top: clamp(20px, 2.6vw, 30px);
}

.page-about .eco-grid__main p {
  margin: 0 0 1.05em;
  font-size: .97rem;
  line-height: 1.85;
  color: var(--ink-soft);
}

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

.page-about .about-eco-card {
  align-self: start;
  transition: transform var(--dur) var(--ease);
}

.page-about .about-eco-card:hover {
  transform: translate(-2px, -3px);
}

.page-about .eco-list {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
}

.page-about .eco-list li {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px dashed rgba(20, 22, 26, .22);
  font-size: .88rem;
}

.page-about .eco-list li:last-child {
  border-bottom: none;
}

.page-about .eco-list__k {
  color: #4a5060;
}

.page-about .eco-list__v {
  font-family: var(--font-mono);
  font-weight: 700;
  color: #14161A;
  white-space: nowrap;
}

.page-about .about-eco-card .paper-card__note a {
  color: #14161A;
  border-bottom: 1px solid rgba(20, 22, 26, .35);
  text-decoration: none;
}

.page-about .about-eco-card .paper-card__note a:hover {
  border-bottom-color: var(--magenta);
  color: var(--magenta);
}

/* ============ 用户场景 ============ */
.page-about .about-users {
  padding: clamp(34px, 4.6vw, 60px) 0 clamp(40px, 5vw, 70px);
}

.page-about .users-strip {
  display: grid;
  gap: 1px;
  margin-top: clamp(22px, 3vw, 34px);
  background: var(--line-soft);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .user-cell {
  background: var(--bg);
  padding: clamp(20px, 2.6vw, 28px) clamp(16px, 2vw, 22px);
  position: relative;
  transition: background var(--dur) var(--ease);
}

.page-about .user-cell:hover {
  background: var(--charcoal);
}

.page-about .user-cell__idx {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: .74rem;
  letter-spacing: .14em;
  color: var(--magenta);
  margin: 0 0 10px;
}

.page-about .user-cell h3 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.02rem;
  line-height: 1.32;
  color: var(--ink);
  margin: 0 0 10px;
}

.page-about .user-cell p {
  margin: 0;
  font-size: .89rem;
  line-height: 1.78;
  color: var(--ink-soft);
}

/* ============ 收尾入口 ============ */
.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px 24px;
  margin-top: clamp(26px, 3.4vw, 40px);
  padding-top: clamp(20px, 2.6vw, 28px);
  border-top: 1px solid var(--line);
}

.page-about .about-cta p {
  flex: 1 1 16ch;
  margin: 0;
  font-size: .95rem;
  line-height: 1.7;
  color: var(--ink-soft);
}

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

/* ============ 窄屏微调 ============ */
@media (max-width: 479px) {
  .page-about .timeline {
    padding-left: 24px;
  }
  .page-about .tl-item::before {
    left: calc(-24px + var(--about-axis-x) - 5px);
  }
  .page-about .source-list__num {
    min-width: 3.6em;
  }
}

/* ============ 平板 ============ */
@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .team-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .users-strip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* ============ 桌面 ============ */
@media (min-width: 960px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: start;
    gap: clamp(30px, 4vw, 56px);
  }
  .page-about .about-hero__media .figure__frame {
    aspect-ratio: 4 / 5;
  }

  .page-about .about-source .grid--12 {
    align-items: start;
  }
  .page-about .about-source__copy {
    grid-column: 1 / span 7;
  }
  .page-about .about-source__figure {
    grid-column: 8 / span 5;
    margin-top: 6px;
  }

  .page-about .eco-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: clamp(28px, 3.6vw, 48px);
  }

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

  .page-about .about-cta {
    flex-wrap: nowrap;
  }
}

/* ============ 大屏 ============ */
@media (min-width: 1280px) {
  .page-about .timeline {
    padding-left: 38px;
  }
  .page-about .tl-item::before {
    left: calc(-38px + var(--about-axis-x) - 5px);
  }
}