.page-about {
  --about-rail: 268px;
  counter-reset: chapter;
  background: var(--ink);
  color: var(--mist);
  font-family: var(--font-body);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: 34px 0 58px;
  border-bottom: 1px solid var(--hair);
  overflow: hidden;
  background:
    radial-gradient(120% 90% at 10% 0%, rgba(61, 44, 141, 0.55) 0%, rgba(11, 18, 32, 0) 62%),
    radial-gradient(90% 70% at 94% 14%, rgba(0, 229, 212, 0.12) 0%, rgba(11, 18, 32, 0) 58%),
    var(--ink);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(90deg, var(--hair) 0 1px, transparent 1px 88px),
    repeating-linear-gradient(0deg, var(--hair) 0 1px, transparent 1px 88px);
  opacity: 0.45;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 88%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 88%);
}

.page-about .about-hero > .wrap {
  position: relative;
  z-index: 1;
}

.page-about .hero-heading {
  margin: 18px 0 0;
}

.page-about .hero-mega {
  display: block;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(64px, 17vw, 178px);
  line-height: 0.82;
  letter-spacing: -0.02em;
  color: var(--white);
}

.page-about .hero-promise {
  display: block;
  margin: 22px 0 0;
  max-width: 22ch;
  font-family: var(--font-head);
  font-weight: 600;
  font-size: clamp(19px, 3.6vw, 30px);
  line-height: 1.38;
  color: var(--cyan);
}

.page-about .hero-sub {
  margin: 18px 0 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .hero-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 38px 0 0;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .fact {
  background: var(--ink-2);
  padding: 18px 18px 20px;
}

.page-about .fact-num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(24px, 4.4vw, 32px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--white);
}

.page-about .fact-num em {
  font-style: normal;
  font-size: 0.58em;
  color: var(--orange);
  margin-left: 2px;
}

.page-about .fact-label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  letter-spacing: 0.05em;
  color: var(--faint);
}

/* ---------- 编号章节 ---------- */
.page-about .chapter {
  counter-increment: chapter;
  position: relative;
  padding: 52px 0;
  border-bottom: 1px solid var(--hair);
}

.page-about .chapter--tint {
  background: var(--ink-3);
}

.page-about .chapter-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
}

.page-about .chapter-rail {
  padding-top: 14px;
  border-top: 2px solid var(--cyan);
}

.page-about .chapter-num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 32px;
  line-height: 1;
  letter-spacing: 0.04em;
  color: rgba(0, 229, 212, 0.85);
}

.page-about .chapter-num::before {
  content: counter(chapter, decimal-leading-zero);
}

.page-about .chapter-title {
  margin: 12px 0 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(24px, 4.2vw, 34px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .chapter-body > p {
  margin: 0 0 16px;
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.88;
  color: var(--muted);
}

.page-about .chapter-body > p:last-of-type {
  margin-bottom: 0;
}

.page-about .chapter-intro {
  margin: 0 0 26px;
  max-width: 68ch;
  font-size: 15.5px;
  line-height: 1.88;
  color: var(--muted);
}

/* ---------- 校验流程 ---------- */
.page-about .flow-figure {
  display: none;
  margin: 0 0 26px;
  padding: 18px 20px;
  border: 1px solid var(--hair);
  background: var(--ink-2);
}

.page-about .flow-svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .step-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .step-card {
  background: var(--ink-2);
  padding: 22px 20px 24px;
  border-top: 2px solid var(--line);
  transition: background-color 0.2s ease;
}

.page-about .step-card:nth-child(1) { border-top-color: var(--cyan); }
.page-about .step-card:nth-child(2) { border-top-color: var(--turf); }
.page-about .step-card:nth-child(3) { border-top-color: var(--orange); }

.page-about .step-card:hover {
  background: var(--ink);
}

.page-about .step-idx {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--faint);
}

.page-about .step-name {
  margin: 12px 0 10px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 19px;
  line-height: 1.25;
  color: var(--white);
}

.page-about .step-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.82;
  color: var(--muted);
}

/* ---------- 发展时间线 ---------- */
.page-about .timeline {
  list-style: none;
  margin: 0 0 30px;
  padding: 0;
  position: relative;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: var(--hair-strong);
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 30px 36px;
}

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

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 1px;
  top: 6px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--cyan);
  box-shadow: 0 0 0 3px rgba(0, 229, 212, 0.1);
  transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

.page-about .tl-item:hover::before {
  background: var(--cyan);
  box-shadow: 0 0 0 6px rgba(0, 229, 212, 0.2);
}

.page-about .tl-year {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.page-about .tl-title {
  margin: 8px 0 8px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 20px;
  line-height: 1.28;
  color: var(--white);
}

.page-about .tl-text {
  margin: 0;
  max-width: 62ch;
  font-size: 14.5px;
  line-height: 1.82;
  color: var(--muted);
}

/* ---------- 团队与规模 ---------- */
.page-about .team-scale {
  margin: 0 0 28px;
}

.page-about .scale-track {
  display: flex;
  height: 48px;
  border: 1px solid var(--hair);
  background: var(--ink-3);
}

.page-about .scale-seg {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding: 0 12px;
  font-size: 15px;
  font-weight: 700;
}

.page-about .scale-seg--a {
  width: 40%;
  background: rgba(0, 229, 212, 0.16);
  color: var(--cyan);
  border-right: 1px solid var(--hair);
}

.page-about .scale-seg--b {
  width: 60%;
  background: rgba(61, 44, 141, 0.42);
  color: var(--mist);
}

.page-about .scale-legend {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .scale-legend li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .scale-legend li .mono {
  margin-left: auto;
  color: var(--white);
}

.page-about .scale-dot {
  flex: none;
  width: 10px;
  height: 10px;
}

.page-about .scale-dot--a { background: var(--cyan); }
.page-about .scale-dot--b { background: var(--indigo); }

.page-about .stat-grid {
  list-style: none;
  margin: 0 0 30px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .stat-cell {
  background: var(--ink-2);
  padding: 20px 18px 22px;
}

.page-about .stat-num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(24px, 4.6vw, 30px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--white);
}

.page-about .stat-num .u {
  font-size: 0.52em;
  font-weight: 400;
  color: var(--faint);
  margin-left: 4px;
}

.page-about .stat-label {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--faint);
}

/* ---------- 覆盖与服务 ---------- */
.page-about .cover-list {
  list-style: none;
  margin: 0 0 30px;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .cover-list li {
  background: var(--ink-2);
  border-left: 2px solid var(--turf);
  padding: 17px 18px;
  font-size: 14.5px;
  line-height: 1.82;
  color: var(--muted);
}

.page-about .cover-list strong {
  color: var(--white);
  font-weight: 600;
}

.page-about .cover-list a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 229, 212, 0.4);
}

.page-about .cover-list a:hover {
  border-bottom-color: var(--cyan);
}

/* ---------- 图 ---------- */
.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--hair);
  background: var(--ink-2);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.7) contrast(1.05);
}

.page-about .about-figure figcaption {
  padding: 12px 16px;
  border-top: 1px solid var(--hair);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--faint);
}

/* ---------- 底部行动区 ---------- */
.page-about .about-cta {
  position: relative;
  padding: 52px 0 56px;
  border-bottom: 1px solid var(--hair);
  background: linear-gradient(118deg, var(--indigo) 0%, var(--ink-2) 60%, var(--ink) 100%);
  overflow: hidden;
}

.page-about .cta-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
}

.page-about .cta-kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--cyan);
}

.page-about .cta-title {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(23px, 4vw, 32px);
  line-height: 1.2;
  color: var(--white);
}

.page-about .cta-text {
  margin: 14px 0 0;
  max-width: 60ch;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: flex-start;
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .hero-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 760px) {
  .page-about .flow-figure {
    display: block;
  }

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

  .page-about .cta-grid {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: end;
    gap: 40px;
  }

  .page-about .cta-actions {
    justify-content: flex-end;
    max-width: 280px;
  }
}

@media (min-width: 960px) {
  .page-about .about-hero {
    padding: 46px 0 72px;
  }

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

  .page-about .chapter-grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 56px;
  }

  .page-about .chapter-rail {
    position: sticky;
    top: 148px;
    align-self: start;
    border-top: none;
    border-left: 2px solid var(--cyan);
    padding: 2px 0 2px 20px;
  }

  .page-about .about-cta {
    padding: 64px 0 68px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-item::before,
  .page-about .step-card {
    transition: none;
  }
}