.page-about {
  background:
    radial-gradient(880px 520px at 90% -6%, rgba(34, 211, 238, 0.12), transparent 60%),
    radial-gradient(720px 460px at 4% 16%, rgba(167, 139, 250, 0.09), transparent 62%);
  padding-bottom: clamp(40px, 7vw, 88px);
}

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

.page-about .breadcrumb {
  padding-top: clamp(14px, 3vw, 26px);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding-block: clamp(22px, 4vw, 40px) clamp(20px, 4vw, 36px);
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(22px, 4vw, 40px);
}

.page-about .about-hero h1 {
  margin: 12px 0 18px;
  font-family: var(--font-head);
  font-size: clamp(30px, 6.4vw, 52px);
  font-weight: 700;
  line-height: 1.18;
  letter-spacing: 0.012em;
  color: var(--ink);
}

.page-about .about-hero .lede {
  margin: 0;
  max-width: 58ch;
  color: var(--ink-dim);
  font-size: clamp(16px, 1.9vw, 18px);
  line-height: 1.78;
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 30px);
}

.page-about .about-hero-facts {
  padding: clamp(20px, 3vw, 28px);
  background:
    linear-gradient(160deg, rgba(17, 26, 51, 0.96), rgba(14, 23, 44, 0.86));
}

.page-about .about-hero-facts .panel-title {
  margin: 0 0 18px;
  font-family: var(--font-head);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--ink-dim);
}

.page-about .fact-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px 12px;
}

.page-about .fact-list .stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .fact-list .stat-num {
  font-size: clamp(21px, 3.4vw, 27px);
  line-height: 1.15;
  color: var(--cyan);
  letter-spacing: 0.02em;
}

.page-about .fact-list .stat-label {
  font-size: 13px;
  color: var(--ink-dim);
}

.page-about .fact-note {
  margin: 20px 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.7;
  color: var(--ink-dim);
}

/* ---------- 章节预览 ---------- */

.page-about .about-toc {
  margin-top: clamp(24px, 4vw, 40px);
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.page-about .toc-label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--ink-dim);
}

.page-about .toc-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .toc-list a {
  display: inline-block;
  padding: 7px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 14px;
  color: var(--ink-dim);
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .toc-list a:hover,
.page-about .toc-list a:focus-visible {
  color: var(--ink);
  border-color: rgba(34, 211, 238, 0.6);
  background: rgba(34, 211, 238, 0.08);
}

/* ---------- 章节骨架 ---------- */

.page-about .about-chapter {
  padding-block: clamp(34px, 6vw, 66px);
}

.page-about .chapter-grid {
  display: grid;
  gap: 14px;
}

.page-about .chapter-index {
  font-family: var(--font-mono);
}

.page-about .chapter-index .eyebrow {
  font-size: 13px;
  letter-spacing: 0.2em;
  color: var(--cyan);
}

.page-about .chapter-body > h2 {
  margin: 0 0 18px;
  font-family: var(--font-head);
  font-size: clamp(24px, 4.2vw, 34px);
  line-height: 1.28;
  color: var(--ink);
}

.page-about .chapter-body > p {
  margin: 0 0 16px;
  max-width: 68ch;
  color: var(--ink-dim);
  font-size: 16px;
  line-height: 1.78;
}

.page-about .chapter-body strong {
  color: var(--ink);
  font-weight: 600;
}

.page-about .serif-quote {
  margin: 28px 0 0;
}

.page-about .serif-quote p {
  font-family: var(--font-serif);
  font-size: clamp(18px, 2.4vw, 22px);
  line-height: 1.7;
  color: var(--ink);
}

/* ---------- 技能树 ---------- */

.page-about .skill-tree {
  margin: 28px 0 32px;
}

.page-about .tree-root {
  display: inline-block;
  padding: 7px 16px;
  border: 1px solid rgba(34, 211, 238, 0.45);
  border-radius: 999px;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .tree-list {
  position: relative;
  margin: 18px 0 0;
  padding: 0 0 0 28px;
  list-style: none;
}

.page-about .tree-list::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 22px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, rgba(34, 211, 238, 0.75), rgba(167, 139, 250, 0.5) 52%, rgba(245, 197, 66, 0.55));
  opacity: 0.7;
}

.page-about .tree-node {
  position: relative;
  padding-bottom: 14px;
}

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

.page-about .tree-node::before {
  content: "";
  position: absolute;
  left: -22px;
  top: 26px;
  width: 22px;
  height: 1px;
  background: var(--line);
}

.page-about .tree-node::after {
  content: "";
  position: absolute;
  left: -26px;
  top: 22px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--node-color, var(--cyan));
  box-shadow: 0 0 10px var(--node-color, var(--cyan));
}

.page-about .tree-node--newbie { --node-color: var(--newbie); }
.page-about .tree-node--classic { --node-color: var(--classic); }
.page-about .tree-node--casual { --node-color: var(--casual); }
.page-about .tree-node--arena { --node-color: var(--arena); }
.page-about .tree-node--violet { --node-color: var(--violet); }
.page-about .tree-node--return { --node-color: var(--ret); }

.page-about .tree-card {
  padding: 16px 18px 18px;
  border-left: 2px solid var(--node-color, var(--cyan));
  transition: transform var(--dur) var(--ease);
}

.page-about .tree-node:hover .tree-card,
.page-about .tree-node:focus-within .tree-card {
  transform: translateX(3px);
}

.page-about .tree-card h3 {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-size: 19px;
  color: var(--ink);
}

.page-about .tree-card h3 .tag {
  font-size: 12px;
}

.page-about .tree-card p {
  margin: 0;
  color: var(--ink-dim);
  font-size: 15px;
  line-height: 1.72;
}

.page-about .tree-jump {
  display: inline-block;
  margin-top: 10px;
  font-size: 14px;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(34, 211, 238, 0.35);
}

.page-about .tree-jump:hover,
.page-about .tree-jump:focus-visible {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

/* ---------- 图片容器 ---------- */

.page-about .img-frame {
  margin: 8px 0 0;
}

.page-about .img-frame img {
  width: 100%;
  object-fit: cover;
}

.page-about .img-cap {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--ink-dim);
}

/* ---------- 时间线 ---------- */

.page-about .history-grid {
  display: grid;
  gap: 28px;
  margin-top: 6px;
}

.page-about .hist-list {
  position: relative;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .hist-list::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 12px;
  bottom: 16px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--gold), rgba(36, 48, 77, 0.85));
}

.page-about .hist-item {
  position: relative;
  padding: 0 0 26px 36px;
}

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

.page-about .hist-item::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 4px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2px solid var(--gold);
  background: var(--bg);
  box-shadow: 0 0 10px rgba(245, 197, 66, 0.4);
}

.page-about .hist-year {
  display: block;
  font-size: 14px;
  letter-spacing: 0.14em;
  color: var(--gold);
}

.page-about .hist-body h3 {
  margin: 6px 0 6px;
  font-family: var(--font-head);
  font-size: 18px;
  color: var(--ink);
}

.page-about .hist-body p {
  margin: 0;
  max-width: 46ch;
  color: var(--ink-dim);
  font-size: 15px;
  line-height: 1.72;
}

.page-about .hist-aside {
  display: grid;
  gap: 20px;
}

.page-about .hist-note {
  padding: 18px 20px;
}

.page-about .hist-note p {
  margin: 0;
  color: var(--ink-dim);
  font-size: 14px;
  line-height: 1.75;
}

.page-about .hist-note .mono {
  color: var(--cyan);
}

/* ---------- 团队标签页 ---------- */

.page-about .tab-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 24px 0 18px;
}

.page-about .tab-panel {
  padding: 20px 22px;
  border-left: 3px solid var(--cyan);
  border-radius: 0 var(--radius) var(--radius) 0;
  background: linear-gradient(180deg, rgba(17, 26, 51, 0.92), rgba(14, 23, 44, 0.72));
}

.page-about .tab-panel h3 {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-size: 19px;
  color: var(--ink);
}

.page-about .tab-panel p {
  margin: 0 0 10px;
  color: var(--ink-dim);
  font-size: 15px;
  line-height: 1.74;
}

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

.page-about .tab-metric {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .tabs + .img-frame {
  margin-top: 30px;
}

/* ---------- 服务原则 ---------- */

.page-about .principle-list {
  display: grid;
  gap: 16px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .principle-item {
  padding: 22px 20px;
  border-top: 2px solid var(--line);
  background: linear-gradient(180deg, rgba(17, 26, 51, 0.55), rgba(11, 18, 36, 0));
}

.page-about .principle-item--entry { border-top-color: var(--cyan); }
.page-about .principle-item--return { border-top-color: var(--gold); }
.page-about .principle-item--reply { border-top-color: var(--violet); }

.page-about .principle-num {
  font-size: 13px;
  letter-spacing: 0.18em;
  color: var(--ink-dim);
}

.page-about .principle-item h3 {
  margin: 10px 0 8px;
  font-family: var(--font-head);
  font-size: 20px;
  color: var(--ink);
}

.page-about .principle-item p {
  margin: 0 0 10px;
  color: var(--ink-dim);
  font-size: 15px;
  line-height: 1.72;
}

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

.page-about .principle-data {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--ink);
  letter-spacing: 0.02em;
}

.page-about .principle-item--entry .principle-data { color: var(--cyan); }
.page-about .principle-item--return .principle-data { color: var(--gold); }
.page-about .principle-item--reply .principle-data { color: var(--violet); }

/* ---------- 收尾 ---------- */

.page-about .about-tail {
  padding-block: clamp(26px, 5vw, 52px);
}

.page-about .tail-panel {
  display: grid;
  gap: 20px;
  padding: clamp(22px, 4vw, 34px);
  background: linear-gradient(120deg, rgba(17, 26, 51, 0.96), rgba(14, 23, 44, 0.78));
}

.page-about .tail-panel h2 {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-size: clamp(22px, 3.4vw, 28px);
  color: var(--ink);
}

.page-about .tail-panel p {
  margin: 0;
  max-width: 62ch;
  color: var(--ink-dim);
  font-size: 15px;
  line-height: 1.76;
}

.page-about .tail-panel .btn {
  justify-self: start;
}

/* ---------- 响应式 ---------- */

@media (min-width: 760px) {
  .page-about .principle-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .tail-panel {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.82fr);
    align-items: start;
  }

  .page-about .chapter-grid {
    grid-template-columns: 86px minmax(0, 1fr);
    gap: 36px;
  }

  .page-about .chapter-index {
    position: sticky;
    top: 104px;
    align-self: start;
    padding-right: 20px;
    text-align: right;
    border-right: 1px solid var(--line);
  }

  .page-about .history-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.85fr);
    gap: 44px;
    align-items: start;
  }

  .page-about .hist-aside {
    position: sticky;
    top: 104px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tree-card,
  .page-about .toc-list a {
    transition: none;
  }
}