.page-about {
  --axis-w: 118px;
  --axis-gap: 40px;
}

.page-about .about-crumb {
  padding-top: 22px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: 40px 0 60px;
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(120% 100% at 88% 0%, rgba(43, 224, 200, 0.10), transparent 58%),
    radial-gradient(90% 90% at 4% 100%, rgba(200, 16, 46, 0.20), transparent 62%),
    linear-gradient(180deg, rgba(22, 50, 79, 0.55), rgba(14, 23, 38, 0));
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(159, 179, 200, 0.055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(159, 179, 200, 0.055) 1px, transparent 1px);
  background-size: 72px 72px;
  -webkit-mask-image: radial-gradient(85% 78% at 45% 35%, #000 25%, transparent 100%);
  mask-image: radial-gradient(85% 78% at 45% 35%, #000 25%, transparent 100%);
  pointer-events: none;
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 36px;
}

.page-about .about-hero-title {
  margin: 14px 0 0;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(34px, 6.4vw, 76px);
  line-height: 1.02;
  letter-spacing: -0.02em;
  max-width: 18ch;
}

.page-about .about-hero-title em {
  font-style: normal;
  color: var(--gold);
  display: inline-block;
  position: relative;
}

.page-about .about-hero-title em::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -0.06em;
  height: 3px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--gold), rgba(232, 178, 26, 0));
}

.page-about .about-hero-lede {
  margin-top: 20px;
  max-width: 52ch;
  color: rgba(233, 237, 242, 0.82);
}

.page-about .about-hero-side {
  border-left: 2px solid rgba(43, 224, 200, 0.4);
  padding-left: 18px;
}

.page-about .about-hero-side-note {
  margin: 0 0 20px;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--steel);
  max-width: 34ch;
}

.page-about .about-hero-stats {
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 14px;
}

.page-about .about-stat dt {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
  margin-bottom: 4px;
}

.page-about .about-stat dd {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: 5px;
}

.page-about .about-stat-num {
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stat-unit {
  font-size: 12.5px;
  color: var(--steel);
}

/* ---------- 主体栅格 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  column-gap: 0;
}

.page-about .about-flow {
  min-width: 0;
}

/* ---------- 左侧时间轴 ---------- */
.page-about .about-axis {
  display: none;
}

/* ---------- 章节通用 ---------- */
.page-about .about-chapter {
  padding: 56px 0 60px;
  border-top: 1px solid var(--line);
}

.page-about .about-flow > .about-chapter:first-child {
  border-top: 0;
  padding-top: 44px;
}

.page-about .about-chapter-head {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 26px;
}

.page-about .about-chapter-heading {
  min-width: 0;
}

.page-about .about-chapter-num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(44px, 8vw, 88px);
  line-height: 0.78;
  letter-spacing: -0.05em;
  color: rgba(232, 178, 26, 0.12);
  -webkit-text-stroke: 1px rgba(232, 178, 26, 0.55);
  user-select: none;
}

.page-about .about-chapter-title {
  margin: 8px 0 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(23px, 3.4vw, 38px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  max-width: 24ch;
}

.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  margin-bottom: 30px;
}

.page-about .about-prose p {
  margin: 0 0 16px;
  font-size: 16.5px;
  line-height: 1.78;
  color: rgba(233, 237, 242, 0.86);
  max-width: 62ch;
  overflow-wrap: break-word;
}

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

.page-about .about-note {
  border-left: 2px solid rgba(232, 178, 26, 0.45);
  padding-left: 16px;
}

.page-about .about-note p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.78;
  color: var(--steel);
  max-width: 40ch;
}

/* ---------- 阶段 ---------- */
.page-about .about-phases {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .about-phase {
  position: relative;
  padding: 22px 20px 24px;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: linear-gradient(160deg, rgba(22, 50, 79, 0.72), rgba(14, 23, 38, 0.42));
  overflow: hidden;
}

.page-about .about-phase::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 3px;
  background: var(--ph, var(--cyan));
  opacity: 0.85;
}

.page-about .about-phase--1 {
  --ph: var(--red);
  --ph-soft: rgba(200, 16, 46, 0.4);
}

.page-about .about-phase--2 {
  --ph: var(--gold);
  --ph-soft: rgba(232, 178, 26, 0.4);
}

.page-about .about-phase--3 {
  --ph: var(--cyan);
  --ph-soft: rgba(43, 224, 200, 0.4);
}

.page-about .about-phase-tag {
  display: inline-block;
  padding: 4px 11px;
  border-radius: 999px;
  border: 1px solid var(--ph-soft, rgba(43, 224, 200, 0.4));
  color: var(--ph, var(--cyan));
  font-size: 12px;
  letter-spacing: 0.1em;
}

.page-about .about-phase h3 {
  margin: 14px 0 10px;
  font-size: 18px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--white);
}

.page-about .about-phase p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(233, 237, 242, 0.74);
}

.page-about .about-stage-figure {
  margin: 26px 0 0;
}

/* ---------- 归档标签墙 ---------- */
.page-about .about-archive-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}

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

.page-about .about-tag {
  display: block;
  flex: 1 1 100%;
  padding: 15px 18px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line-strong);
  background: rgba(22, 50, 79, 0.5);
  color: var(--white);
  text-decoration: none;
  transition: background 0.25s var(--ease), border-color 0.25s var(--ease), transform 0.25s var(--ease);
}

.page-about .about-tag:nth-child(3n) {
  border-radius: 999px;
  padding-inline: 24px;
}

.page-about .about-tag:nth-child(3n + 2) {
  background: rgba(14, 23, 38, 0.72);
}

.page-about .about-tag:hover,
.page-about .about-tag:focus-visible {
  border-color: rgba(43, 224, 200, 0.55);
  background: rgba(22, 50, 79, 0.85);
  transform: translateY(-2px);
  outline: none;
}

.page-about .about-tag-name {
  display: block;
  font-size: 15.5px;
  line-height: 1.4;
}

.page-about .about-tag-desc {
  display: block;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  margin-top: 0;
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--steel);
  transition: max-height 0.28s var(--ease), opacity 0.28s var(--ease), margin-top 0.28s var(--ease);
}

.page-about .about-tag:hover .about-tag-desc,
.page-about .about-tag:focus-visible .about-tag-desc {
  max-height: 60px;
  opacity: 1;
  margin-top: 8px;
}

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

/* ---------- 团队四象限 ---------- */
.page-about .about-quad {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-quad-cell {
  padding: 22px 20px 24px;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: var(--qc, rgba(22, 50, 79, 0.6));
}

.page-about .about-quad-cell--a {
  --qc: linear-gradient(165deg, rgba(200, 16, 46, 0.24), rgba(14, 23, 38, 0.55));
  --qk: var(--red);
}

.page-about .about-quad-cell--b {
  --qc: linear-gradient(165deg, rgba(232, 178, 26, 0.18), rgba(14, 23, 38, 0.55));
  --qk: var(--gold);
}

.page-about .about-quad-cell--c {
  --qc: linear-gradient(165deg, rgba(43, 224, 200, 0.18), rgba(14, 23, 38, 0.55));
  --qk: var(--cyan);
}

.page-about .about-quad-cell--d {
  --qc: linear-gradient(165deg, rgba(124, 142, 163, 0.26), rgba(14, 23, 38, 0.55));
  --qk: var(--steel);
}

.page-about .about-quad-name {
  display: block;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--qk, var(--gold));
  margin-bottom: 10px;
}

.page-about .about-quad-cell h3 {
  margin: 0 0 10px;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--white);
}

.page-about .about-quad-cell p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(233, 237, 242, 0.75);
}

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

/* ---------- 更新指标 ---------- */
.page-about .about-metrics {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.page-about .about-metric {
  padding: 24px 20px 26px;
  background: rgba(14, 23, 38, 0.88);
}

.page-about .about-metric-num {
  display: block;
  font-size: clamp(22px, 2.6vw, 30px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--gold);
  font-variant-numeric: tabular-nums;
}

.page-about .about-metric-label {
  display: block;
  margin-top: 6px;
  font-size: 12.5px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .about-metric p {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.72;
  color: rgba(233, 237, 242, 0.72);
}

/* ---------- 同栏模拟看板 ---------- */
.page-about .about-screen {
  border-radius: var(--radius-lg);
  border: 1px solid var(--line-strong);
  background: linear-gradient(160deg, rgba(22, 50, 79, 0.68), rgba(10, 18, 32, 0.94));
  overflow: hidden;
}

.page-about .about-screen-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--line);
  background: rgba(10, 18, 32, 0.62);
}

.page-about .about-screen-meta {
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--steel);
}

.page-about .about-screen-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
}

.page-about .about-screen-col {
  padding: 20px 18px 22px;
  min-width: 0;
}

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

.page-about .about-screen-title {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--cyan);
}

.page-about .about-screen-list {
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 11px;
}

.page-about .about-screen-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 14.5px;
  line-height: 1.65;
  color: rgba(233, 237, 242, 0.82);
}

.page-about .about-screen-list li::before {
  content: "";
  flex: 0 0 auto;
  width: 5px;
  height: 5px;
  margin-top: 9px;
  border-radius: 50%;
  background: var(--cyan);
}

.page-about .about-window {
  display: inline-flex;
  gap: 4px;
  margin-top: 18px;
  padding: 4px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(10, 18, 32, 0.72);
}

.page-about .about-window-item {
  font-size: 12.5px;
  padding: 5px 13px;
  border-radius: 999px;
  color: var(--steel);
}

.page-about .about-window-item.is-on {
  background: rgba(43, 224, 200, 0.16);
  color: var(--cyan);
}

/* ---------- 服务范围 ---------- */
.page-about .about-facts {
  margin: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.page-about .about-fact {
  padding: 16px 18px;
  background: rgba(22, 50, 79, 0.42);
}

.page-about .about-fact dt {
  margin-bottom: 5px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .about-fact dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
  color: var(--white);
  overflow-wrap: break-word;
}

/* ---------- 结尾入口 ---------- */
.page-about .about-next {
  padding: 56px 0 8px;
  border-top: 1px solid var(--line);
}

.page-about .about-next-head {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 26px;
}

.page-about .about-next-title {
  margin: 8px 0 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(23px, 3.2vw, 34px);
  line-height: 1.2;
  letter-spacing: -0.01em;
}

.page-about .about-next-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-next-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  text-decoration: none;
  color: inherit;
  transition: transform 0.24s var(--ease), border-color 0.24s var(--ease);
}

.page-about .about-next-card:hover,
.page-about .about-next-card:focus-visible {
  transform: translateY(-3px);
  border-color: rgba(232, 178, 26, 0.5);
  outline: none;
}

.page-about .about-next-index {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--gold);
}

.page-about .about-next-card h3 {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--white);
}

.page-about .about-next-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: rgba(233, 237, 242, 0.74);
}

.page-about .about-next-go {
  margin-top: auto;
  padding-top: 10px;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--cyan);
}

.page-about .about-tail {
  padding: 34px 0 8px;
  display: flex;
  justify-content: flex-end;
}

/* ---------- 进入视口 ---------- */
.page-about .reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.28s var(--ease), transform 0.28s var(--ease);
}

.page-about .reveal.is-in {
  opacity: 1;
  transform: none;
}

/* ---------- 中屏 ---------- */
@media (min-width: 700px) {
  .page-about .about-tag {
    flex: 1 1 46%;
  }

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

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

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

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

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

/* ---------- 宽屏 ---------- */
@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 52px 0 68px;
  }

  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.62fr);
    align-items: end;
    gap: 48px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    gap: 40px;
  }

  .page-about .about-archive-layout {
    grid-template-columns: minmax(0, 1.28fr) minmax(0, 0.72fr);
    gap: 40px;
  }

  .page-about .about-tag {
    flex: 1 1 45%;
  }

  .page-about .about-screen-cols {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .page-about .about-screen-col + .about-screen-col {
    border-top: 0;
    border-left: 1px solid var(--line);
  }

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

@media (min-width: 1080px) {
  .page-about .about-body {
    grid-template-columns: var(--axis-w) minmax(0, 1fr);
    column-gap: var(--axis-gap);
  }

  .page-about .about-axis {
    display: block;
    position: relative;
  }

  .page-about .about-axis-inner {
    position: sticky;
    top: calc(var(--header-h, 88px) + 34px);
    display: flex;
    flex-direction: column;
    gap: 26px;
    padding: 78px 0 40px;
  }

  .page-about .about-axis-inner::before {
    content: "";
    position: absolute;
    left: 9px;
    top: 84px;
    bottom: 48px;
    width: 1px;
    background: linear-gradient(180deg, rgba(232, 178, 26, 0.55), rgba(43, 224, 200, 0.35), rgba(159, 179, 200, 0.14));
  }

  .page-about .about-node {
    position: relative;
    display: block;
    padding-left: 30px;
    font-size: 12.5px;
    letter-spacing: 0.1em;
    line-height: 1.4;
    color: var(--mist);
    text-decoration: none;
    transition: color 0.25s var(--ease);
  }

  .page-about .about-node::before {
    content: "";
    position: absolute;
    left: 4px;
    top: 2px;
    width: 11px;
    height: 11px;
    border-radius: 50%;
    border: 1px solid var(--line-strong);
    background: var(--ink);
    transition: background 0.25s var(--ease), border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
  }

  .page-about .about-node:hover,
  .page-about .about-node:focus-visible {
    color: var(--white);
    outline: none;
  }

  .page-about .about-node:hover::before,
  .page-about .about-node:focus-visible::before {
    border-color: rgba(43, 224, 200, 0.8);
  }

  .page-about .about-node[aria-current="true"] {
    color: var(--white);
  }

  .page-about .about-node[aria-current="true"]::before {
    background: var(--gold);
    border-color: var(--gold-light);
    box-shadow: 0 0 0 5px rgba(232, 178, 26, 0.16);
  }

  .page-about .about-chapter {
    padding: 72px 0 76px;
  }

  .page-about .about-chapter-num {
    -webkit-text-stroke-width: 1.2px;
  }

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

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

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

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

  .page-about .about-tail {
    padding-bottom: 24px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .page-about .about-tag,
  .page-about .about-tag-desc,
  .page-about .about-next-card,
  .page-about .about-node::before {
    transition: none;
  }
}