.page-about {
  --about-gutter: 20px;
  --about-rail-w: 216px;
  --about-radius: 3px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--night);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero-media {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.page-about .about-hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.42;
  filter: saturate(0.85) contrast(1.06);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background:
    radial-gradient(120% 90% at 82% 8%, rgba(139, 108, 240, 0.34), transparent 62%),
    radial-gradient(90% 70% at 6% 92%, rgba(49, 228, 210, 0.16), transparent 66%),
    linear-gradient(180deg, rgba(10, 19, 34, 0.6) 0%, rgba(10, 19, 34, 0.9) 68%, var(--night) 100%);
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 2;
  padding-block: 72px 48px;
}

.page-about .about-hero-eyebrow {
  margin-top: 28px;
}

.page-about .about-hero-title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(30px, 6.2vw, 56px);
  line-height: 1.14;
  letter-spacing: -0.01em;
  color: var(--cream);
  max-width: 20ch;
}

.page-about .about-hero-lead {
  margin: 20px 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--ink);
}

.page-about .about-hero-stats {
  margin-top: 32px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  border-top: 1px solid var(--line);
  padding-top: 20px;
}

.page-about .about-hero-stats .stat {
  display: grid;
  gap: 4px;
  padding-left: 12px;
  border-left: 2px solid var(--cyan);
}

.page-about .about-hero-stats .stat:nth-child(2) { border-left-color: var(--violet); }
.page-about .about-hero-stats .stat:nth-child(3) { border-left-color: var(--amber); }

.page-about .about-hero-stats .stat-value {
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 700;
  color: var(--cream);
  line-height: 1.1;
}

.page-about .about-hero-stats .stat-unit {
  font-style: normal;
  font-size: 13px;
  margin-left: 2px;
  color: var(--stone);
}

.page-about .about-hero-stats .stat-label {
  font-size: 12px;
  color: var(--stone);
  letter-spacing: 0.02em;
}

/* ---------- 布局骨架 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px;
  padding-block: 44px 72px;
}

/* ---------- 左侧轨道 ---------- */
.page-about .about-rail-title {
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--stone);
  margin: 0 0 12px;
}

.page-about .about-rail-track {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 14px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail-track::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 16px;
  bottom: 16px;
  width: 1px;
  background: linear-gradient(180deg, var(--clay), var(--moss), var(--cyan), var(--violet));
  opacity: 0.45;
  display: none;
}

.page-about .about-rail-item { flex: 0 0 auto; }

.page-about .about-rail-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
  border-radius: var(--about-radius);
  border: 1px solid transparent;
  text-decoration: none;
  color: var(--stone);
  font-size: 14px;
  white-space: nowrap;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-rail-link:hover {
  color: var(--cream);
  border-color: var(--line);
}

.page-about .about-rail-link.is-active {
  color: var(--cyan);
  background: var(--cyan-soft);
  border-color: rgba(49, 228, 210, 0.32);
}

.page-about .about-rail-link:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .about-rail-idx {
  font-size: 11px;
  letter-spacing: 0.04em;
  opacity: 0.75;
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  padding-block: 40px;
  border-bottom: 1px solid var(--line);
}

.page-about .about-section:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-section .section-summary {
  max-width: 62ch;
}

/* ---------- 01 来路 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin-top: 28px;
}

.page-about .about-split-main .prose {
  margin: 0 0 18px;
  max-width: 68ch;
}

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

.page-about .about-split-side {
  padding: 22px 20px;
  display: grid;
  gap: 2px;
  align-content: start;
}

.page-about .about-side-key {
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--stone);
  margin: 12px 0 0;
}

.page-about .about-side-key:first-child { margin-top: 0; }

.page-about .about-side-val {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
  color: var(--cream);
}

.page-about .about-side-val:last-child {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

/* ---------- 02 版本轨道 ---------- */
.page-about .about-track {
  margin-top: 32px;
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  position: relative;
}

.page-about .about-track-item {
  display: grid;
  gap: 12px;
  align-content: start;
  padding: 22px 20px 24px;
  background: var(--night-2);
  border: 1px solid var(--line);
  border-top-width: 3px;
  border-radius: var(--about-radius);
  position: relative;
  overflow: hidden;
}

.page-about .about-track-item::after {
  content: "";
  position: absolute;
  right: -40px;
  top: -40px;
  width: 140px;
  height: 140px;
  border-radius: 50%;
  opacity: 0.1;
  pointer-events: none;
}

.page-about .about-track-item--v1 { border-top-color: var(--clay); }
.page-about .about-track-item--v1::after { background: var(--clay); }
.page-about .about-track-item--v2 { border-top-color: var(--moss); }
.page-about .about-track-item--v2::after { background: var(--moss); }
.page-about .about-track-item--v3 {
  border-top-color: var(--cyan);
  background: linear-gradient(165deg, rgba(139, 108, 240, 0.14), rgba(18, 32, 54, 0.96) 55%);
}
.page-about .about-track-item--v3::after { background: var(--cyan); }

.page-about .about-track-tag {
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin: 0;
  color: var(--stone);
}

.page-about .about-track-item--v1 .about-track-tag { color: var(--clay); }
.page-about .about-track-item--v2 .about-track-tag { color: var(--moss); }
.page-about .about-track-item--v3 .about-track-tag { color: var(--cyan); }

.page-about .about-track-item .track-title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 20px;
  line-height: 1.3;
  color: var(--cream);
}

.page-about .about-track-item .track-body {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink);
}

.page-about .about-track-list {
  list-style: none;
  margin: 4px 0 0;
  padding: 0;
  display: grid;
  gap: 8px;
  border-top: 1px dashed var(--line);
  padding-top: 14px;
}

.page-about .about-track-list li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--stone);
}

.page-about .about-track-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--line-strong);
}

.page-about .about-track-item--v3 .about-track-list li::before { background: var(--cyan); }

/* ---------- 03 团队 ---------- */
.page-about .about-team-figure {
  margin: 28px 0 24px;
}

.page-about .about-team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.page-about .about-role {
  background: var(--rock);
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  overflow: hidden;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-role[open] {
  border-color: rgba(49, 228, 210, 0.36);
  background: linear-gradient(180deg, rgba(49, 228, 210, 0.07), var(--rock) 60%);
}

.page-about .about-role-head {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 15px 18px;
  cursor: pointer;
  list-style: none;
}

.page-about .about-role-head::-webkit-details-marker { display: none; }

.page-about .about-role-head::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  line-height: 1;
  color: var(--cyan);
  transition: transform var(--dur) var(--ease);
}

.page-about .about-role[open] .about-role-head::after {
  content: "–";
}

.page-about .about-role-head:focus-visible {
  outline: 2px solid var(--violet);
  outline-offset: -2px;
}

.page-about .about-role-idx {
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--violet);
}

.page-about .about-role-name {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  color: var(--cream);
}

.page-about .about-role-body {
  padding: 0 18px 18px;
  border-top: 1px solid var(--line);
  margin-top: 4px;
  padding-top: 14px;
}

.page-about .about-role-body p {
  margin: 0 0 12px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink);
}

.page-about .about-role-note {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.02em;
  color: var(--moss);
  padding: 8px 12px;
  background: rgba(127, 176, 140, 0.1);
  border-left: 2px solid var(--moss);
  border-radius: 0 var(--about-radius) var(--about-radius) 0;
}

/* ---------- 04 赛后节奏 ---------- */
.page-about .about-section--flow {
  background:
    linear-gradient(180deg, rgba(11, 22, 38, 0.7), transparent 40%),
    repeating-linear-gradient(90deg, rgba(147, 160, 180, 0.07) 0 1px, transparent 1px 80px),
    var(--rock);
}

.page-about .about-flow-figure {
  margin: 26px 0 24px;
}

.page-about .about-flow-steps {
  list-style: none;
  margin: 0;
  padding: 0 0 0 26px;
  border-left: 1px solid var(--line);
  display: grid;
  gap: 26px;
}

.page-about .about-flow-step {
  position: relative;
}

.page-about .about-flow-step::before {
  content: "";
  position: absolute;
  left: -32px;
  top: 6px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--night);
  border: 2px solid var(--stone);
}

.page-about .about-flow-step:nth-child(1)::before { border-color: var(--clay); }
.page-about .about-flow-step:nth-child(2)::before { border-color: var(--moss); }
.page-about .about-flow-step:nth-child(3)::before { border-color: var(--cyan); }
.page-about .about-flow-step:nth-child(4)::before {
  border-color: var(--amber);
  box-shadow: 0 0 0 4px var(--amber-soft);
}

.page-about .about-flow-time {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--stone);
  margin-bottom: 6px;
}

.page-about .about-flow-title {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 18px;
  line-height: 1.35;
  color: var(--cream);
}

.page-about .about-flow-step p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink);
  max-width: 62ch;
}

/* ---------- 05 长期准则 ---------- */
.page-about .about-promise-list {
  list-style: none;
  margin: 32px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-promise {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 16px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  align-items: start;
}

.page-about .about-promise-idx {
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px var(--stone);
  letter-spacing: 0.02em;
}

.page-about .about-promise h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 18px;
  line-height: 1.35;
  color: var(--cream);
}

.page-about .about-promise p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink);
  max-width: 64ch;
}

.page-about .about-promise a,
.page-about .about-eco-card a,
.page-about .about-eco-foot a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(49, 228, 210, 0.4);
}

.page-about .about-promise a:hover,
.page-about .about-eco-card a:hover,
.page-about .about-eco-foot a:hover {
  border-bottom-color: var(--cyan);
}

/* ---------- 06 协作生态 ---------- */
.page-about .about-eco-grid {
  margin-top: 28px;
}

.page-about .about-eco-card {
  padding: 20px 18px;
  display: grid;
  gap: 8px;
  align-content: start;
}

.page-about .about-eco-key {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--stone);
}

.page-about .about-eco-val {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  color: var(--amber);
  line-height: 1.1;
}

.page-about .about-eco-desc {
  margin: 4px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink);
}

.page-about .about-eco-foot {
  margin: 28px 0 0;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  color: var(--stone);
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .about-hero-inner {
    padding-block: 96px 64px;
  }

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

  .page-about .about-track {
    gap: 20px;
  }

  .page-about .about-promise {
    grid-template-columns: 64px 1fr;
    gap: 22px;
  }

  .page-about .about-promise-idx {
    font-size: 34px;
  }
}

@media (min-width: 960px) {
  .page-about {
    --about-gutter: 32px;
  }

  .page-about .about-hero-inner {
    padding-block: 120px 76px;
  }

  .page-about .about-hero-lead {
    font-size: 17px;
  }

  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 56px;
    padding-block: 72px 108px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 92px;
    align-self: start;
  }

  .page-about .about-rail-track {
    display: grid;
    gap: 2px;
    overflow: visible;
    padding-left: 14px;
  }

  .page-about .about-rail-track::before {
    display: block;
  }

  .page-about .about-rail-link {
    white-space: normal;
  }

  .page-about .about-section {
    padding-block: 56px;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-track {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0;
    align-items: stretch;
    border-top: 1px solid var(--line);
  }

  .page-about .about-track-item {
    border: 0;
    border-top: 3px solid var(--line);
    border-radius: 0;
    margin-top: -1px;
    background: transparent;
    padding: 24px 22px 26px;
  }

  .page-about .about-track-item + .about-track-item {
    border-left: 1px solid var(--line);
  }

  .page-about .about-track-item--v1 { border-top-color: var(--clay); }
  .page-about .about-track-item--v2 { border-top-color: var(--moss); }
  .page-about .about-track-item--v3 {
    border-top-color: var(--cyan);
    background: linear-gradient(180deg, rgba(139, 108, 240, 0.16), transparent 70%);
  }

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

  .page-about .about-flow-steps {
    padding-left: 34px;
    gap: 32px;
  }

  .page-about .about-flow-step::before {
    left: -40px;
    width: 13px;
    height: 13px;
  }

  .page-about .about-eco-foot {
    font-size: 15px;
  }
}

@media (min-width: 1180px) {
  .page-about .about-section {
    padding-block: 64px;
  }

  .page-about .about-track-item {
    padding: 28px 26px 30px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail-link,
  .page-about .about-role,
  .page-about .about-role-head::after {
    transition: none;
  }
}