.page-about {
  position: relative;
  overflow-x: clip;
  color: var(--text);
  background:
    radial-gradient(820px 500px at 84% -6%, rgba(42, 107, 255, .15), transparent 64%),
    radial-gradient(640px 420px at 4% 20%, rgba(108, 76, 241, .10), transparent 62%);
}

.page-about::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: linear-gradient(to right, var(--hair) 1px, transparent 1px);
  background-size: 108px 100%;
  opacity: .2;
  -webkit-mask-image: linear-gradient(to bottom, #000 0, transparent 44%);
  mask-image: linear-gradient(to bottom, #000 0, transparent 44%);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding: 86px 0 46px;
  border-bottom: 1px solid var(--hair);
}

.page-about .about-crumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
  font-size: 13px;
  color: var(--text-2);
}

.page-about .about-crumb li {
  display: flex;
  align-items: center;
}

.page-about .about-crumb li + li::before {
  content: "/";
  padding: 0 9px;
  color: var(--hair);
}

.page-about .about-crumb a {
  color: var(--text-2);
  text-decoration: none;
  transition: color .18s var(--ease);
}

.page-about .about-crumb a:hover {
  color: var(--cyan);
}

.page-about .about-crumb [aria-current="page"] {
  color: var(--text);
}

.page-about .about-hero__eyebrow {
  margin: 0;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  max-width: 20ch;
  font-size: clamp(30px, 5.4vw, 52px);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.12;
}

.page-about .about-hero__lede {
  margin: 22px 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--text-2);
}

.page-about .about-hero__marks {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.page-about .about-hero__marks li {
  padding: 6px 13px;
  font-size: 13px;
  color: var(--text-2);
  border: 1px solid var(--hair);
  border-radius: var(--r-pill);
  background: var(--glass);
}

/* ---------- 通用区块 ---------- */

.page-about .about-section {
  position: relative;
  padding: 52px 0;
  border-bottom: 1px solid var(--hair);
}

.page-about .about-section:last-of-type {
  border-bottom: 0;
  padding-bottom: 84px;
}

.page-about .about-section__head {
  margin-bottom: 26px;
}

.page-about .about-section__num {
  display: block;
  margin-bottom: 12px;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
}

.page-about .about-section__title {
  margin: 0;
  font-size: clamp(22px, 3.3vw, 32px);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.24;
}

.page-about .about-section__note {
  margin: 12px 0 0;
  max-width: 60ch;
  font-size: 14px;
  line-height: 1.74;
  color: var(--text-2);
}

.page-about .about-p {
  max-width: 66ch;
  margin: 0 0 1.1em;
  font-size: 16px;
  line-height: 1.78;
  color: var(--text-2);
}

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

.page-about .about-p strong {
  color: var(--text);
  font-weight: 600;
}

/* ---------- 立场三格 ---------- */

.page-about .stance {
  display: grid;
  gap: 12px;
  margin-top: 28px;
}

.page-about .stance__item {
  padding: 20px 18px;
  border: 1px solid var(--hair);
  border-radius: var(--r-md);
  background: var(--slate);
  transition: border-color .2s var(--ease);
}

.page-about .stance__item:hover {
  border-color: rgba(34, 211, 238, .3);
}

.page-about .stance__k {
  display: block;
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--cyan);
}

.page-about .stance__t {
  margin: 10px 0 0;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .stance__d {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-2);
}

/* ---------- 不提供清单 ---------- */

.page-about .excl {
  list-style: none;
  display: grid;
  gap: 1px;
  margin: 26px 0 0;
  padding: 0;
  border: 1px solid var(--hair);
  border-radius: var(--r-md);
  overflow: hidden;
  background: var(--hair);
}

.page-about .excl__row {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 14px 16px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-2);
  background: var(--void);
}

.page-about .excl__row::before {
  content: "—";
  flex: 0 0 auto;
  font-family: var(--mono);
  color: var(--amber);
}

/* ---------- 图片 ---------- */

.page-about .about-figure {
  margin: 30px 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--hair);
  border-radius: var(--r-md);
  background: var(--slate);
}

.page-about .about-figure__cap {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.68;
  color: var(--text-2);
}

/* ---------- 版本轨道 ---------- */

.page-about .track {
  display: grid;
  gap: 4px;
  margin: 30px 0 0;
}

.page-about .vnode {
  position: relative;
  padding: 12px 0 12px 24px;
  border-left: 1px solid var(--hair);
}

.page-about .vnode::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 17px;
  width: 9px;
  height: 9px;
  border-radius: 2px;
  background: var(--cyan);
  box-shadow: 0 0 0 3px rgba(34, 211, 238, .13);
}

.page-about .vnode--violet::before {
  background: var(--violet);
  box-shadow: 0 0 0 3px rgba(108, 76, 241, .18);
}

.page-about .vnode--violet .vnode__ver {
  color: var(--violet);
}

.page-about .vnode > summary {
  display: flex;
  flex-direction: column;
  gap: 4px;
  list-style: none;
  cursor: pointer;
  outline: none;
  -webkit-tap-highlight-color: transparent;
}

.page-about .vnode > summary::-webkit-details-marker {
  display: none;
}

.page-about .vnode > summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 4px;
  border-radius: var(--r-xs);
}

.page-about .vnode__ver {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--cyan);
}

.page-about .vnode__label {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
}

.page-about .vnode > summary:hover .vnode__label {
  color: var(--cyan);
}

.page-about .vnode__body {
  margin: 10px 0 0;
  max-width: 34ch;
  font-size: 13px;
  line-height: 1.72;
  color: var(--text-2);
}

/* ---------- 复核流程 ---------- */

.page-about .flow {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
}

.page-about .flow__step {
  position: relative;
  padding: 0 0 26px 30px;
  border-left: 1px solid var(--hair);
}

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

.page-about .flow__idx {
  position: absolute;
  left: 0;
  top: 1px;
  transform: translateX(-50%);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 22px;
  min-width: 26px;
  padding: 0 6px;
  font-size: 11px;
  letter-spacing: .04em;
  color: var(--void);
  background: var(--cyan);
  border-radius: var(--r-pill);
  box-shadow: 0 0 0 4px var(--void);
}

.page-about .flow__title {
  margin: 0;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .flow__text {
  margin: 8px 0 0;
  max-width: 58ch;
  font-size: 14px;
  line-height: 1.74;
  color: var(--text-2);
}

.page-about .flow__tip {
  margin: 8px 0 0;
  max-width: 58ch;
  padding-left: 12px;
  border-left: 2px solid rgba(34, 211, 238, .42);
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-2);
  transition: border-color .2s var(--ease), color .2s var(--ease);
}

.page-about .flow__step:hover .flow__tip {
  border-left-color: var(--cyan);
  color: var(--text);
}

/* ---------- 覆盖范围 ---------- */

.page-about .scale {
  display: grid;
  gap: 12px;
  margin-top: 28px;
}

.page-about .scale__item {
  padding: 18px 16px;
  border: 1px solid var(--hair);
  border-radius: var(--r-md);
  background: var(--slate);
}

.page-about .scale__num {
  display: block;
  font-size: 30px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .scale__label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-2);
}

/* ---------- 术语 ---------- */

.page-about .terms {
  display: grid;
  gap: 10px;
  margin-top: 28px;
}

.page-about .term {
  border: 1px solid var(--hair);
  border-radius: var(--r-md);
  background: var(--slate);
  transition: border-color .22s var(--ease);
}

.page-about .term[open] {
  border-color: rgba(34, 211, 238, .34);
}

.page-about .term > summary {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 15px 16px;
  list-style: none;
  cursor: pointer;
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  outline: none;
  -webkit-tap-highlight-color: transparent;
}

.page-about .term > summary::-webkit-details-marker {
  display: none;
}

.page-about .term > summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -3px;
  border-radius: var(--r-md);
}

.page-about .term > summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--mono);
  font-size: 16px;
  line-height: 1;
  color: var(--cyan);
  transition: color .2s var(--ease);
}

.page-about .term[open] > summary::after {
  content: "−";
}

.page-about .term__body {
  margin: 0;
  padding: 14px 16px 16px;
  border-top: 1px solid var(--hair);
}

.page-about .term__row {
  margin: 0 0 10px;
  font-size: 13px;
  line-height: 1.74;
  color: var(--text-2);
}

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

.page-about .term__k {
  display: inline-block;
  min-width: 62px;
  margin-right: 6px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--cyan);
}

.page-about .term__row--no .term__k {
  color: var(--text-2);
}

/* ---------- 服务地区与延伸 ---------- */

.page-about .about-contact {
  display: grid;
  gap: 14px;
  margin-top: 26px;
}

.page-about .about-contact__panel {
  padding: 22px 20px;
  border: 1px solid var(--hair);
  border-radius: var(--r-md);
  background: var(--slate);
}

.page-about .about-contact__h {
  margin: 0 0 10px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .about-contact__p {
  margin: 0 0 14px;
  font-size: 14px;
  line-height: 1.74;
  color: var(--text-2);
}

.page-about .about-link {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--brand);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 1px solid rgba(42, 107, 255, .42);
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

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

.page-about .about-index {
  margin-top: 34px;
  padding-top: 26px;
  border-top: 1px solid var(--hair);
}

.page-about .about-index__title {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
}

.page-about .about-index__list {
  list-style: none;
  display: grid;
  gap: 1px;
  margin: 0;
  padding: 0;
  border: 1px solid var(--hair);
  border-radius: var(--r-md);
  overflow: hidden;
  background: var(--hair);
}

.page-about .about-index__list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 14px;
  padding: 13px 16px;
  font-size: 14px;
  background: var(--slate);
}

.page-about .about-index__list a {
  color: var(--text);
  font-weight: 600;
  text-decoration: none;
  padding-bottom: 1px;
  border-bottom: 1px solid transparent;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

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

.page-about .about-index__list span {
  font-size: 13px;
  line-height: 1.66;
  color: var(--text-2);
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .scale {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .page-about .stance {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 820px) {
  .page-about .track {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .vnode {
    padding: 26px 10px 12px 0;
    border-left: 0;
    border-top: 1px solid var(--hair);
  }

  .page-about .vnode::before {
    left: 0;
    top: -5px;
  }

  .page-about .vnode__body {
    max-width: 100%;
  }

  .page-about .about-contact {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 16px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 104px 0 54px;
  }

  .page-about .about-section {
    padding: 72px 0;
  }

  .page-about .about-section:last-of-type {
    padding-bottom: 104px;
  }

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

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

  .page-about .flow__step {
    padding-bottom: 30px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .vnode,
  .page-about .term,
  .page-about .stance__item,
  .page-about .flow__tip,
  .page-about .about-link,
  .page-about .about-index__list a {
    transition: none;
  }
}
</main>