.page-about {
  --about-rule: rgba(11, 95, 255, .10);
  --about-shadow: 0 3px 14px rgba(16, 22, 31, .07);
  background-color: var(--paper);
}

/* ============ 首屏专题封面 ============ */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(22px, 4vw, 44px) 0 clamp(34px, 5vw, 62px);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(120% 100% at 88% 0%, rgba(255, 107, 26, .10), transparent 58%),
    linear-gradient(180deg, rgba(11, 95, 255, .07), rgba(11, 95, 255, 0) 72%),
    var(--paper);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--about-rule) 1px, transparent 1px),
    linear-gradient(90deg, var(--about-rule) 1px, transparent 1px);
  background-size: 46px 46px;
  -webkit-mask-image: linear-gradient(180deg, #000 0%, transparent 88%);
  mask-image: linear-gradient(180deg, #000 0%, transparent 88%);
  pointer-events: none;
}

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

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  margin-top: 16px;
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(32px, 5.6vw, 58px);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--ink);
  margin: 10px 0 0;
  max-width: 760px;
}

.page-about .about-lede {
  margin: 18px 0 0;
  max-width: 62ch;
  font-size: 17px;
  line-height: 1.85;
  color: var(--graphite);
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero-badge {
  position: relative;
  overflow: hidden;
  padding: 20px 22px 22px;
  border-radius: var(--radius-lg);
  background: var(--ink);
  color: #fff;
  box-shadow: var(--shadow-island);
}

.page-about .about-hero-badge::after {
  content: "";
  position: absolute;
  right: -34px;
  top: -34px;
  width: 128px;
  height: 128px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 107, 26, .40), transparent 68%);
  pointer-events: none;
}

.page-about .badge-label {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, .62);
}

.page-about .badge-num {
  margin: 8px 0 10px;
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: 54px;
  line-height: 1;
  color: var(--orange);
}

.page-about .badge-note {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: rgba(255, 255, 255, .80);
}

.page-about .about-stats {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(28px, 4vw, 46px) 0 0;
  padding: 0;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.page-about .about-stats li {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 15px 16px;
  background: var(--card);
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: clamp(22px, 3vw, 28px);
  line-height: 1;
  color: var(--blue);
}

.page-about .stat-label {
  font-size: 13px;
  color: var(--graphite);
}

/* ============ 主体骨架 ============ */
.page-about .about-body {
  padding-block: clamp(34px, 5vw, 64px);
}

.page-about .rail-main {
  min-width: 0;
}

.page-about .about-section {
  scroll-margin-top: calc(var(--header-h) + 26px);
  padding-bottom: clamp(38px, 5.5vw, 68px);
}

.page-about .about-section + .about-section {
  padding-top: clamp(34px, 5vw, 58px);
  border-top: 1px solid var(--line);
}

.page-about .about-section .section-title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 3.4vw, 36px);
  line-height: 1.18;
  letter-spacing: -0.005em;
  color: var(--ink);
  margin: 0 0 16px;
}

.page-about .file-tab {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 14px;
  padding: 5px 13px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--blue);
  background: var(--blue-soft);
  border: 1px solid rgba(11, 95, 255, .22);
  border-radius: var(--radius-pill);
}

.page-about .file-tab::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--orange);
  flex: none;
}

.page-about .section-more {
  margin: clamp(18px, 2.6vw, 26px) 0 0;
  padding-left: 14px;
  border-left: 3px solid var(--orange);
  font-size: 15px;
  line-height: 1.8;
  color: var(--graphite);
}

.page-about .section-more a {
  color: var(--blue);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ============ 图版 ============ */
.page-about .about-media {
  margin: clamp(22px, 3vw, 34px) 0 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--card);
  overflow: hidden;
  box-shadow: var(--about-shadow);
}

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

.page-about .about-media figcaption {
  padding: 10px 16px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .02em;
  color: var(--graphite);
}

/* ============ 制造工序条 ============ */
.page-about .process-track {
  list-style: none;
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  counter-reset: none;
}

.page-about .process-step {
  position: relative;
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 16px;
  padding-bottom: 24px;
}

.page-about .process-step::before {
  content: "";
  position: absolute;
  left: 21px;
  top: 46px;
  bottom: 4px;
  width: 1px;
  background: var(--line);
}

.page-about .process-step:last-child {
  padding-bottom: 0;
}

.page-about .process-step:last-child::before {
  display: none;
}

.page-about .step-idx {
  position: relative;
  z-index: 1;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  border: 1px solid var(--blue);
  background: var(--card);
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 13px;
  color: var(--blue);
}

.page-about .step-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 19px;
  line-height: 1.3;
  color: var(--ink);
  margin: 9px 0 6px;
}

.page-about .step-text {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--graphite);
  max-width: 62ch;
}

/* ============ 认证条 ============ */
.page-about .cert-band {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: clamp(22px, 3vw, 30px);
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.page-about .cert-item {
  padding: 16px 18px;
  background: var(--card);
}

.page-about .cert-code {
  position: relative;
  margin: 0;
  padding-left: 16px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 12.5px;
  letter-spacing: .12em;
  color: var(--teal);
}

.page-about .cert-code::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 7px;
  height: 7px;
  margin-top: -3.5px;
  border-radius: 50%;
  background: var(--teal);
}

.page-about .cert-name {
  margin: 6px 0 0;
  padding-left: 16px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--graphite);
}

/* ============ 产品线折叠 ============ */
.page-about .line-stack {
  display: grid;
  gap: 10px;
  margin-top: clamp(20px, 3vw, 28px);
}

.page-about .line-stack .fold {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  transition: border-color .22s ease, box-shadow .22s ease;
}

.page-about .line-stack .fold[open] {
  border-color: rgba(11, 95, 255, .32);
  box-shadow: var(--about-shadow);
}

.page-about .line-stack .fold-summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 14px;
  padding: 15px 18px;
  color: var(--ink);
}

.page-about .line-stack .fold-summary::-webkit-details-marker {
  display: none;
}

.page-about .line-code {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--blue);
  background: var(--blue-soft);
  border-radius: var(--radius-sm);
  padding: 3px 8px;
}

.page-about .line-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 20px;
  line-height: 1.2;
}

.page-about .line-tag {
  margin-left: auto;
  padding: 3px 11px;
  font-size: 12px;
  color: var(--graphite);
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  transition: color .22s ease, background-color .22s ease, border-color .22s ease;
}

.page-about .line-stack .fold[open] .line-tag {
  color: var(--orange-deep);
  background: var(--orange-soft);
  border-color: var(--orange-soft);
}

.page-about .line-stack .fold-body {
  padding: 0 18px 18px;
}

.page-about .line-stack .fold-body p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--graphite);
}

.page-about .line-keys {
  list-style: none;
  display: grid;
  gap: 9px;
  margin: 14px 0 0;
  padding: 0;
}

.page-about .line-keys li {
  display: grid;
  grid-template-columns: 78px minmax(0, 1fr);
  gap: 12px;
  font-size: 15px;
  line-height: 1.75;
}

.page-about .line-keys .key {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--blue);
  padding-top: 4px;
}

.page-about .line-keys .val {
  color: var(--graphite);
}

/* ============ 版本轨道 ============ */
.page-about .version-rail {
  list-style: none;
  display: flex;
  gap: 12px;
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding: 0 0 10px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
}

.page-about .version-rail::-webkit-scrollbar {
  height: 6px;
}

.page-about .version-rail::-webkit-scrollbar-thumb {
  background: var(--line);
  border-radius: 3px;
}

.page-about .vnode {
  position: relative;
  flex: 0 0 auto;
  min-width: 116px;
  padding: 18px 14px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--card);
  scroll-snap-align: start;
}

.page-about .vnode::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 3px;
  border-radius: var(--radius-md) var(--radius-md) 0 0;
  background: var(--line);
}

.page-about .vnode.is-current {
  border-color: rgba(255, 107, 26, .48);
  background: var(--orange-soft);
}

.page-about .vnode.is-current::before {
  background: var(--orange);
}

.page-about .vid {
  display: block;
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: 25px;
  line-height: 1;
  color: var(--ink);
}

.page-about .vnode.is-current .vid {
  color: var(--orange-deep);
}

.page-about .vlbl {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  color: var(--graphite);
}

/* ============ 变更条目 ============ */
.page-about .change-list {
  list-style: none;
  display: grid;
  gap: 1px;
  margin: clamp(18px, 2.6vw, 26px) 0 0;
  padding: 0;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.page-about .change-list li {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 12px;
  padding: 14px 18px;
  background: var(--card);
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
}

.page-about .change-no {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 12px;
  color: var(--orange-deep);
  padding-top: 4px;
}

/* ============ 服务片区 ============ */
.page-about .region-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: clamp(20px, 3vw, 28px);
}

.page-about .region-card {
  position: relative;
  overflow: hidden;
  padding: 18px 18px 22px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  transition: transform .24s ease, box-shadow .24s ease, border-color .24s ease;
}

.page-about .region-card::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--blue), var(--blue-deep));
  transform: scaleX(.22);
  transform-origin: left;
  transition: transform .28s ease;
}

.page-about .region-card:hover,
.page-about .region-card:focus-visible {
  transform: translateY(-3px);
  border-color: rgba(11, 95, 255, .28);
  box-shadow: var(--about-shadow);
}

.page-about .region-card:hover::after,
.page-about .region-card:focus-visible::after {
  transform: scaleX(1);
}

.page-about .region-code {
  display: block;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .16em;
  color: var(--blue);
}

.page-about .region-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 21px;
  line-height: 1.25;
  color: var(--ink);
  margin: 7px 0 9px;
}

.page-about .region-text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--graphite);
}

/* ============ 承诺带 ============ */
.page-about .promise-band {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  margin-top: clamp(22px, 3vw, 32px);
  padding: clamp(20px, 3vw, 32px);
  border-radius: var(--radius-lg);
  background:
    linear-gradient(135deg, rgba(11, 95, 255, .22), rgba(11, 95, 255, 0) 62%),
    var(--ink);
  box-shadow: var(--shadow-island);
}

.page-about .promise-item {
  padding-left: 16px;
  border-left: 2px solid rgba(255, 107, 26, .55);
}

.page-about .promise-num {
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: clamp(30px, 4.4vw, 44px);
  line-height: 1;
  color: var(--orange);
}

.page-about .promise-unit {
  margin-left: 4px;
  font-family: var(--font-mono);
  font-size: 16px;
  color: rgba(255, 255, 255, .72);
}

.page-about .promise-text {
  margin: 10px 0 0;
  font-size: 14.5px;
  line-height: 1.76;
  color: rgba(255, 255, 255, .80);
  max-width: 34ch;
}

/* ============ 转化块 ============ */
.page-about .about-cta {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
  margin-top: clamp(24px, 3.4vw, 38px);
  padding: clamp(22px, 3vw, 30px);
  border: 1px solid rgba(11, 95, 255, .18);
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(11, 95, 255, .09), rgba(255, 107, 26, .10));
}

.page-about .about-cta h3 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(20px, 2.5vw, 27px);
  line-height: 1.24;
  color: var(--ink);
  margin: 0 0 10px;
}

.page-about .about-cta p {
  margin: 0;
  max-width: 60ch;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--graphite);
}

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

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

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

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

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 8fr) minmax(0, 3fr);
    gap: 44px;
    align-items: end;
  }
}

@media (min-width: 1080px) {
  .page-about .region-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 1200px) {
  .page-about .process-track {
    padding-left: 6px;
  }
}

@media (max-width: 420px) {
  .page-about .about-stats {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .line-keys li {
    grid-template-columns: minmax(0, 1fr);
    gap: 2px;
  }

  .page-about .line-keys .key {
    padding-top: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .region-card,
  .page-about .region-card::after,
  .page-about .line-stack .fold,
  .page-about .line-tag {
    transition: none;
  }

  .page-about .region-card:hover,
  .page-about .region-card:focus-visible {
    transform: none;
  }
}