.page-about {
  --about-line: rgba(143, 163, 191, .22);
  --about-line-strong: rgba(69, 243, 228, .32);
  --about-track: rgba(69, 243, 228, .18);
}

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

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 18px 0 8px;
}

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
  padding: 20px 0 50px;
}

.page-about .kicker {
  margin: 0 0 14px;
  color: var(--cyan);
  font-size: 12px;
  letter-spacing: .22em;
  text-transform: uppercase;
}

.page-about h1 {
  margin: 0 0 20px;
  font-size: clamp(34px, 8vw, 62px);
  line-height: 1.1;
  font-weight: 900;
  letter-spacing: .03em;
  color: var(--ice);
  text-wrap: balance;
}

.page-about h2 {
  margin: 0 0 14px;
  font-size: clamp(26px, 5.2vw, 42px);
  line-height: 1.16;
  font-weight: 800;
  letter-spacing: .04em;
  color: var(--ice);
}

.page-about h3 {
  margin: 0 0 8px;
  font-size: 18px;
  line-height: 1.4;
  font-weight: 700;
  letter-spacing: .03em;
  color: var(--ice);
}

.page-about p {
  margin: 0 0 1em;
  font-size: 16px;
  line-height: 1.78;
  color: rgba(232, 241, 255, .8);
  max-width: 68ch;
}

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

.page-about .about-lead {
  font-size: 17px;
  line-height: 1.85;
  color: rgba(232, 241, 255, .88);
  max-width: 56ch;
}

.page-about .about-lead--soft {
  color: var(--mist);
  font-size: 15px;
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(132px, 1fr));
  gap: 16px;
  margin: 26px 0 28px;
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-left: 12px;
  border-left: 2px solid var(--about-line-strong);
}

.page-about .about-stat-num {
  font-size: 21px;
  font-weight: 600;
  letter-spacing: .04em;
  color: var(--cyan);
}

.page-about .about-stat-label {
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--mist);
}

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

/* 框景窗口 */
.page-about .about-frame {
  position: relative;
  margin: 0;
  padding: 10px;
  border: 1px solid var(--about-line-strong);
  border-radius: var(--radius-lg);
  background:
    linear-gradient(158deg, rgba(69, 243, 228, .12), rgba(155, 108, 255, .10) 58%, rgba(6, 10, 18, 0) 100%);
}

.page-about .about-frame::before,
.page-about .about-frame::after {
  content: "";
  position: absolute;
  width: 15px;
  height: 15px;
  border: 1px solid var(--amber);
  pointer-events: none;
}

.page-about .about-frame::before {
  top: -1px;
  left: -1px;
  border-right: 0;
  border-bottom: 0;
  border-top-left-radius: var(--radius-lg);
}

.page-about .about-frame::after {
  right: -1px;
  bottom: -1px;
  border-left: 0;
  border-top: 0;
  border-bottom-right-radius: var(--radius-lg);
}

.page-about .about-frame img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border-radius: calc(var(--radius-lg) - 8px);
  object-fit: cover;
}

.page-about .about-frame figcaption,
.page-about .about-tl-figure figcaption,
.page-about .team-figure figcaption {
  margin-top: 10px;
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--mist);
  line-height: 1.6;
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  padding: 54px 0;
  border-top: 1px solid var(--about-line);
}

.page-about .about-head {
  margin-bottom: 34px;
  max-width: 60ch;
}

.page-about .about-sub {
  color: var(--mist);
  font-size: 15px;
}

/* ---------- 服务对象 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
}

.page-about .who-list {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--about-line);
}

.page-about .who-item {
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 14px;
  padding: 20px 0;
  border-bottom: 1px solid var(--about-line);
  transition: background .3s var(--ease);
}

.page-about .who-item:hover {
  background: rgba(69, 243, 228, .04);
}

.page-about .who-mark {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  font-size: 12px;
  color: var(--cyan);
  border: 1px solid var(--about-line-strong);
  border-radius: var(--radius-sm);
  background: rgba(69, 243, 228, .07);
}

.page-about .who-item h3 {
  font-size: 17px;
}

.page-about .who-item p {
  font-size: 15px;
  line-height: 1.75;
  color: rgba(232, 241, 255, .72);
}

/* ---------- 技能树 ---------- */
.page-about .tree {
  display: grid;
  justify-items: start;
}

.page-about .tree-root {
  position: relative;
  width: 100%;
  padding: 20px;
  border: 1px solid var(--about-line-strong);
  border-radius: var(--radius-md);
  background: linear-gradient(140deg, rgba(69, 243, 228, .1), rgba(14, 23, 40, .95));
}

.page-about .tree-root h3 {
  font-size: 20px;
  color: var(--cyan);
}

.page-about .tree-root p {
  font-size: 14.5px;
  color: rgba(232, 241, 255, .76);
  max-width: 58ch;
}

.page-about .tree-tag {
  display: inline-block;
  margin-bottom: 8px;
  padding: 2px 8px;
  font-size: 11px;
  letter-spacing: .16em;
  border-radius: var(--radius-sm);
  color: var(--ice);
  background: rgba(143, 163, 191, .16);
}

.page-about .tree-tag--cyan {
  color: var(--cyan);
  background: rgba(69, 243, 228, .12);
}

.page-about .tree-tag--violet {
  color: var(--violet);
  background: rgba(155, 108, 255, .16);
}

.page-about .tree-tag--amber {
  color: var(--amber);
  background: rgba(255, 180, 84, .14);
}

.page-about .tree-stem {
  width: 2px;
  height: 26px;
  margin-left: 26px;
  background: linear-gradient(var(--cyan), rgba(69, 243, 228, 0));
}

.page-about .tree-branches {
  display: grid;
  gap: 14px;
  width: 100%;
}

.page-about .tree-node {
  position: relative;
  padding: 18px;
  border: 1px solid var(--about-line);
  border-radius: var(--radius-md);
  background: var(--ink-panel);
  transition: border-color .28s var(--ease), transform .28s var(--ease), background .28s var(--ease);
}

.page-about .tree-node:hover,
.page-about .tree-node:focus-visible {
  border-color: var(--cyan);
  background: rgba(69, 243, 228, .06);
  transform: translateY(-2px);
  outline: none;
}

.page-about .tree-node h3 {
  font-size: 18px;
}

.page-about .tree-node p {
  font-size: 14.5px;
  line-height: 1.72;
  color: rgba(232, 241, 255, .74);
}

.page-about .tree-link {
  display: inline-block;
  margin-top: 4px;
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(69, 243, 228, .35);
  transition: border-color .25s var(--ease), color .25s var(--ease);
}

.page-about .tree-link:hover {
  color: var(--ice);
  border-bottom-color: var(--ice);
}

/* ---------- 时间线 ---------- */
.page-about .about-tl-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
}

.page-about .tl {
  margin: 0 0 0 4px;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--about-line);
  display: grid;
  gap: 24px;
}

.page-about .tl-item {
  position: relative;
  padding-left: 22px;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  top: 7px;
  left: -5px;
  width: 9px;
  height: 9px;
  border: 1px solid var(--cyan);
  border-radius: 2px;
  background: var(--ink-void);
  transform: rotate(45deg);
  transition: background .28s var(--ease), box-shadow .28s var(--ease);
}

.page-about .tl-item:hover::before,
.page-about .tl-item:focus-within::before {
  background: var(--cyan);
  box-shadow: 0 0 12px rgba(69, 243, 228, .55);
}

.page-about .tl-num {
  display: inline-block;
  margin-bottom: 6px;
  font-size: 12.5px;
  letter-spacing: .2em;
  color: var(--cyan);
}

.page-about .tl-item h3 {
  font-size: 17px;
  margin-bottom: 6px;
}

.page-about .tl-item p {
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(232, 241, 255, .72);
  max-width: 54ch;
}

.page-about .about-tl-figure {
  margin: 0;
  padding: 10px;
  border: 1px solid var(--about-line);
  border-radius: var(--radius-md);
  background: rgba(14, 23, 40, .72);
}

.page-about .about-tl-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border-radius: calc(var(--radius-md) - 6px);
  object-fit: cover;
}

/* ---------- 团队 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

.page-about .team-figure {
  margin: 0;
  padding: 10px;
  border: 1px solid var(--about-line);
  border-radius: var(--radius-lg);
  background:
    radial-gradient(circle at 30% 20%, rgba(155, 108, 255, .14), transparent 62%),
    rgba(14, 23, 40, .8);
}

.page-about .team-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border-radius: calc(var(--radius-lg) - 8px);
  object-fit: cover;
}

.page-about .team-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 26px;
}

.page-about .team-stat {
  padding: 14px;
  border: 1px solid var(--about-line);
  border-radius: var(--radius-sm);
  background: rgba(14, 23, 40, .7);
  transition: border-color .28s var(--ease);
}

.page-about .team-stat:hover {
  border-color: var(--about-line-strong);
}

.page-about .team-stat-num {
  display: block;
  font-size: 20px;
  font-weight: 600;
  letter-spacing: .04em;
  color: var(--amber);
}

.page-about .team-stat-label {
  display: block;
  margin-top: 4px;
  font-size: 12.5px;
  letter-spacing: .05em;
  color: var(--mist);
  line-height: 1.5;
}

/* ---------- 服务方式（暖纸层） ---------- */
.page-about .principles {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .principle {
  position: relative;
  padding: 22px 20px 20px;
  border-radius: var(--radius-md);
  color: var(--ink-deep);
}

.page-about .principle h3 {
  color: var(--ink-deep);
  font-size: 18px;
  margin-top: 26px;
}

.page-about .principle p {
  color: rgba(17, 24, 39, .78);
  font-size: 14.5px;
  line-height: 1.75;
  max-width: none;
}

.page-about .principle-num {
  position: absolute;
  top: 16px;
  left: 20px;
  font-size: 13px;
  letter-spacing: .18em;
  color: rgba(17, 24, 39, .42);
}

/* ---------- 收尾入口 ---------- */
.page-about .about-outro {
  padding: 10px 0 64px;
}

.page-about .about-next {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
  padding: 26px 22px;
  border: 1px solid var(--about-line-strong);
  border-radius: var(--radius-lg);
}

.page-about .about-next-copy h2 {
  font-size: clamp(22px, 4.6vw, 30px);
}

.page-about .about-next-copy p {
  font-size: 14.5px;
  color: var(--mist);
  max-width: 48ch;
}

.page-about .about-next-links {
  display: grid;
  gap: 8px;
}

.page-about .next-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border: 1px solid var(--about-line);
  border-radius: var(--radius-sm);
  font-size: 14.5px;
  color: var(--ice);
  text-decoration: none;
  background: rgba(6, 10, 18, .5);
  transition: border-color .26s var(--ease), background .26s var(--ease), transform .26s var(--ease);
}

.page-about .next-link .mono {
  font-size: 11.5px;
  letter-spacing: .16em;
  color: var(--cyan);
}

.page-about .next-link:hover,
.page-about .next-link:focus-visible {
  border-color: var(--cyan);
  background: rgba(69, 243, 228, .08);
  transform: translateX(3px);
  outline: none;
}

.page-about .next-link--amber {
  border-color: rgba(255, 180, 84, .38);
}

.page-about .next-link--amber .mono {
  color: var(--amber);
}

.page-about .next-link--amber:hover,
.page-about .next-link--amber:focus-visible {
  border-color: var(--amber);
  background: rgba(255, 180, 84, .1);
}

/* ---------- 桌面端 ---------- */
@media (min-width: 760px) {
  .page-about .about-hero-grid {
    grid-template-columns: 1.06fr .94fr;
    align-items: start;
    gap: 40px;
    padding: 26px 0 62px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, .82fr) minmax(0, 1.18fr);
    gap: 42px;
    align-items: start;
  }

  .page-about .tree-branches {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
    position: relative;
    padding-top: 26px;
  }

  .page-about .tree-branches::before {
    content: "";
    position: absolute;
    top: 0;
    left: 16.6%;
    right: 16.6%;
    height: 2px;
    background: var(--about-track);
  }

  .page-about .tree-stem {
    margin: 0 auto;
  }

  .page-about .tree-root {
    justify-self: center;
    max-width: 640px;
  }

  .page-about .tree {
    justify-items: center;
  }

  .page-about .tree-node::before {
    content: "";
    position: absolute;
    top: -27px;
    left: 50%;
    width: 2px;
    height: 27px;
    background: var(--about-track);
  }

  .page-about .about-tl-grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, .9fr);
    gap: 46px;
    align-items: start;
  }

  .page-about .tl-item:nth-child(even) {
    margin-left: clamp(16px, 4vw, 52px);
  }

  .page-about .about-tl-figure {
    position: sticky;
    top: 96px;
  }

  .page-about .team-grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
    gap: 46px;
    align-items: center;
  }

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

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

  .page-about .principle:nth-child(2) {
    margin-top: 26px;
  }

  .page-about .principle:nth-child(3) {
    margin-top: -8px;
  }

  .page-about .about-next {
    grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr);
    gap: 34px;
    align-items: center;
    padding: 34px 32px;
  }

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

@media (min-width: 1080px) {
  .page-about .about-hero-grid {
    gap: 56px;
  }

  .page-about .about-section {
    padding: 66px 0;
  }

  .page-about .tree-node {
    padding: 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tree-node,
  .page-about .next-link,
  .page-about .who-item,
  .page-about .team-stat {
    transition: none;
  }

  .page-about .tree-node:hover,
  .page-about .next-link:hover {
    transform: none;
  }
}