.page-about {
  --about-rail: 88px;
  --about-gap: 44px;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  padding-top: calc(var(--step) * 5);
  padding-bottom: calc(var(--step) * 2);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-bottom: calc(var(--step) * 8);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: calc(var(--step) * -6);
  right: calc(var(--step) * -8);
  width: 62%;
  height: 76%;
  background:
    radial-gradient(circle at 32% 30%, rgba(34, 211, 238, 0.16), transparent 62%),
    radial-gradient(circle at 74% 66%, rgba(240, 180, 41, 0.1), transparent 58%);
  pointer-events: none;
}

.page-about .about-hero-grid {
  position: relative;
  display: grid;
  gap: calc(var(--step) * 5);
}

.page-about .about-hero-copy .section-kicker {
  margin-bottom: calc(var(--step) * 2);
}

.page-about .about-hero-copy h1 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(30px, 7.4vw, 62px);
  line-height: 1.14;
  letter-spacing: -0.01em;
  color: var(--text);
  max-width: 20ch;
}

.page-about .about-hero-lead {
  margin: calc(var(--step) * 3) 0 0;
  max-width: 54ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--frame);
  margin-top: calc(var(--step) * 4);
  border: var(--frame) solid var(--line);
  border-radius: var(--r-s);
  background: var(--line);
  overflow: hidden;
}

.page-about .hero-stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: calc(var(--step) * 2) calc(var(--step) * 2.5);
  background: var(--panel);
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 500;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: 0.02em;
}

.page-about .stat-label {
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.page-about .about-hero-figure {
  border-radius: var(--r-m);
}

/* ---------- 流程轨道 ---------- */
.page-about .flow-block {
  position: relative;
}

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

.page-about .flow-rail {
  display: none;
}

.page-about .flow-content {
  padding-bottom: calc(var(--step) * 9);
}

.page-about .flow-lead {
  margin: calc(var(--step) * 2.5) 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .inline-link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(34, 211, 238, 0.45);
  padding-bottom: 1px;
  transition: border-color 180ms ease, color 180ms ease;
}

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

/* ---------- 团队技能树 ---------- */
.page-about .team-split {
  display: grid;
  gap: calc(var(--step) * 5);
  margin-top: calc(var(--step) * 6);
}

.page-about .tree {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 calc(var(--step) * 4);
}

.page-about .tree::before {
  content: "";
  position: absolute;
  left: 0;
  top: calc(var(--step) * 2);
  bottom: calc(var(--step) * 2);
  width: var(--frame);
  background: linear-gradient(180deg, var(--cyan), var(--line) 34%, var(--line));
}

.page-about .tree-item {
  position: relative;
  padding: calc(var(--step) * 2.5) 0 calc(var(--step) * 3) calc(var(--step) * 3);
  border-bottom: 1px dashed var(--line);
}

.page-about .tree-item:last-child {
  border-bottom: 0;
  padding-bottom: calc(var(--step) * 1.5);
}

.page-about .tree-item::before {
  content: "";
  position: absolute;
  left: calc(var(--step) * -4);
  top: calc(var(--step) * 4.5);
  width: calc(var(--step) * 4);
  height: var(--frame);
  background: var(--line);
}

.page-about .tree-item::after {
  content: "";
  position: absolute;
  left: calc(var(--step) * -4 - 3px);
  top: calc(var(--step) * 4.5 - 3px);
  width: 8px;
  height: 8px;
  border: var(--frame) solid var(--line);
  border-radius: 50%;
  background: var(--ink);
}

.page-about [data-section][data-state="active"] .tree-item::after {
  border-color: var(--cyan);
}

.page-about .tree-head {
  display: flex;
  align-items: baseline;
  gap: calc(var(--step) * 1.5);
}

.page-about .tree-index {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--archive);
}

.page-about .tree-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 20px;
  letter-spacing: 0.01em;
  color: var(--text);
}

.page-about .tree-desc {
  margin: calc(var(--step) * 1.5) 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .tree-tags {
  display: flex;
  flex-wrap: wrap;
  gap: calc(var(--step) * 1);
  margin: calc(var(--step) * 2) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .tree-tags li {
  padding: 4px 10px;
  border: 1px solid var(--line);
  border-radius: var(--r-s);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--archive);
  background: rgba(124, 144, 174, 0.06);
}

.page-about .about-tree-figure {
  border-radius: var(--r-m);
}

/* ---------- 版本时间轴 ---------- */
.page-about .version-jump {
  display: flex;
  align-items: center;
  gap: calc(var(--step) * 1);
  margin-top: calc(var(--step) * 4);
}

.page-about .version-jump-label {
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--archive);
  margin-right: calc(var(--step) * 0.5);
}

.page-about .version-jump a {
  display: inline-block;
  padding: 5px 12px;
  border: var(--frame) solid var(--line);
  border-radius: var(--r-s);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--muted);
  text-decoration: none;
  transition: border-color 180ms ease, color 180ms ease, transform 180ms ease;
}

.page-about .version-jump a:hover,
.page-about .version-jump a:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
  transform: translateY(-2px);
}

.page-about .version-track {
  list-style: none;
  margin: calc(var(--step) * 5) 0 0;
  padding: 0;
}

.page-about .version-item {
  position: relative;
  padding-left: calc(var(--step) * 5);
  padding-bottom: calc(var(--step) * 4);
}

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

.page-about .version-item::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 24px;
  bottom: 0;
  width: var(--frame);
  background: var(--line);
}

.page-about .version-item:last-child::before {
  display: none;
}

.page-about .version-dot {
  position: absolute;
  left: 0;
  top: 12px;
  width: 12px;
  height: 12px;
  border: var(--frame) solid var(--cyan);
  border-radius: 2px;
  background: var(--ink);
  transform: rotate(45deg);
  transition: background 180ms ease;
}

.page-about [data-section][data-state="active"] .version-dot {
  background: rgba(34, 211, 238, 0.35);
}

.page-about .version-card {
  padding: calc(var(--step) * 3);
}

.page-about .version-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: calc(var(--step) * 1.5);
  margin-bottom: calc(var(--step) * 2);
}

.page-about .version-no {
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 500;
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

.page-about .version-card .panel-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 21px;
  line-height: 1.4;
  color: var(--text);
}

.page-about .version-card p {
  margin: calc(var(--step) * 1.5) 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .version-figure {
  margin-top: calc(var(--step) * 5);
  border-radius: var(--r-m);
}

.page-about .version-figure-cap {
  margin-top: calc(var(--step) * 1.5);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--archive);
}

/* ---------- 设备适配 ---------- */
.page-about .device-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: calc(var(--step) * 2);
  margin: calc(var(--step) * 5) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .device-cell {
  padding: calc(var(--step) * 2.5);
  border: var(--frame) solid var(--line);
  border-radius: var(--r-s);
  background: var(--panel);
  transition: border-color 180ms ease, transform 180ms ease;
}

.page-about .device-cell:hover {
  border-color: rgba(34, 211, 238, 0.55);
  transform: translateY(-2px);
}

.page-about .device-name {
  display: block;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--cyan);
}

.page-about .device-cell p {
  margin: calc(var(--step) * 1.25) 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .device-note {
  margin-top: calc(var(--step) * 4);
}

/* ---------- 资料节奏 ---------- */
.page-about .cadence-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: calc(var(--step) * 2.5);
  margin-top: calc(var(--step) * 5);
}

.page-about .cadence-cell {
  position: relative;
  padding: calc(var(--step) * 3);
  border: var(--frame) solid var(--line);
  border-radius: var(--r-m);
  background:
    linear-gradient(160deg, rgba(124, 144, 174, 0.14), rgba(17, 27, 49, 0) 62%),
    var(--panel);
}

.page-about .cadence-num {
  font-family: var(--font-mono);
  font-size: 44px;
  font-weight: 500;
  line-height: 1;
  letter-spacing: 0.01em;
  color: var(--text);
}

.page-about .cadence-unit {
  margin-left: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.05em;
  color: var(--archive);
}

.page-about .cadence-title {
  margin: calc(var(--step) * 2) 0 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 18px;
  color: var(--text);
}

.page-about .cadence-cell p {
  margin: calc(var(--step) * 1.25) 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 联系信息带 ---------- */
.page-about .about-contact {
  padding: calc(var(--step) * 4) 0 calc(var(--step) * 9);
}

.page-about .contact-band {
  display: grid;
  gap: calc(var(--step) * 4);
  padding: calc(var(--step) * 4) calc(var(--step) * 3);
  border: var(--frame) solid var(--line);
  border-radius: var(--r-l);
  background:
    linear-gradient(120deg, rgba(240, 180, 41, 0.09), rgba(34, 211, 238, 0.07) 52%, rgba(10, 16, 32, 0) 88%),
    var(--panel);
  box-shadow: var(--shadow-hard);
}

.page-about .contact-band-head .section-kicker {
  margin-bottom: calc(var(--step) * 1.5);
}

.page-about .contact-band-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(24px, 5.4vw, 38px);
  line-height: 1.2;
  letter-spacing: -0.005em;
  color: var(--text);
}

.page-about .contact-band-note {
  margin: calc(var(--step) * 2) 0 0;
  max-width: 52ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .contact-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--frame);
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: var(--frame) solid var(--line);
  border-radius: var(--r-s);
  overflow: hidden;
}

.page-about .contact-item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: calc(var(--step) * 2) calc(var(--step) * 2.5);
  background: var(--ink);
}

.page-about .contact-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--archive);
  text-transform: uppercase;
}

.page-about .contact-value {
  font-size: 15px;
  line-height: 1.6;
  color: var(--text);
  word-break: break-word;
}

.page-about .contact-item--wide .contact-value {
  font-size: 14px;
  color: var(--muted);
}

.page-about .contact-band-foot {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: calc(var(--step) * 2);
}

.page-about .contact-tip {
  margin: 0;
  max-width: 46ch;
  font-size: 14px;
  line-height: 1.75;
  color: var(--archive);
}

/* ---------- 中屏 ---------- */
@media (min-width: 640px) {
  .page-about .hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

  .page-about .cadence-cell:last-child {
    grid-column: 1 / -1;
  }

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

  .page-about .contact-item--wide {
    grid-column: 1 / -1;
  }

  .page-about .contact-band-foot {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    align-items: center;
    gap: calc(var(--step) * 6);
  }

  .page-about .about-hero {
    padding-bottom: calc(var(--step) * 12);
  }

  .page-about .flow-grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    column-gap: var(--about-gap);
  }

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

  .page-about .flow-rail::before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    right: 0;
    width: var(--frame);
    background: var(--line);
  }

  .page-about .flow-node {
    position: absolute;
    top: 0;
    right: 0;
    transform: translateX(50%);
    display: grid;
    place-items: center;
    width: 40px;
    height: 40px;
    border: var(--frame) solid var(--line);
    border-radius: var(--r-s);
    background: var(--ink);
    font-family: var(--font-mono);
    font-size: 13px;
    font-weight: 500;
    letter-spacing: 0.04em;
    color: var(--archive);
    transition: border-color 200ms ease, color 200ms ease;
  }

  .page-about [data-section][data-state="active"] .flow-node {
    border-color: var(--cyan);
    color: var(--cyan);
  }

  .page-about .flow-content {
    padding-bottom: calc(var(--step) * 12);
  }

  .page-about .team-split {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    align-items: start;
    gap: calc(var(--step) * 6);
  }

  .page-about .version-track {
    margin-top: calc(var(--step) * 6);
  }
}

@media (min-width: 1024px) {
  .page-about .device-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .cadence-cell:last-child {
    grid-column: auto;
  }

  .page-about .contact-band {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
    align-items: start;
    column-gap: calc(var(--step) * 6);
    padding: calc(var(--step) * 6) calc(var(--step) * 6);
  }

  .page-about .contact-band-head {
    grid-column: 1;
  }

  .page-about .contact-list {
    grid-column: 2;
    grid-row: 1 / span 2;
  }

  .page-about .contact-band-foot {
    grid-column: 1;
  }
}
<<<END>>>