.page-about {
  --about-rail-w: 218px;
  --about-gap: clamp(26px, 4.4vw, 72px);
  --about-sec-gap: clamp(46px, 6.5vw, 92px);
  position: relative;
  display: block;
  color: var(--white);
  background:
    radial-gradient(120% 55% at 10% 0%, rgba(43, 47, 122, 0.55), transparent 62%),
    radial-gradient(90% 40% at 92% 12%, rgba(53, 224, 232, 0.08), transparent 60%);
  font-family: var(--font-sans);
}

/* ---------- 面包屑与首屏 ---------- */
.page-about .about-top {
  position: relative;
  padding-top: clamp(18px, 3vw, 34px);
}

.page-about .breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 clamp(24px, 3.6vw, 44px);
  padding: 0;
  list-style: none;
  font-size: 13px;
  color: var(--muted);
}

.page-about .breadcrumbs a {
  color: var(--muted);
  text-decoration: none;
  transition: color 0.25s var(--ease-out);
}

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

.page-about .breadcrumbs li + li::before {
  content: "/";
  margin-right: 8px;
  color: rgba(153, 162, 201, 0.5);
}

.page-about .about-hero {
  position: relative;
  padding: clamp(34px, 5.5vw, 76px) 0 clamp(34px, 4.6vw, 62px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -12% -8% -30% -12%;
  background:
    radial-gradient(46% 58% at 18% 16%, rgba(164, 107, 255, 0.26), transparent 70%),
    radial-gradient(42% 52% at 88% 46%, rgba(53, 224, 232, 0.13), transparent 72%);
  pointer-events: none;
  z-index: 0;
}

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

.page-about .about-hero::after {
  content: "";
  display: block;
  height: 2px;
  margin-top: clamp(30px, 4vw, 52px);
  background: linear-gradient(90deg, var(--violet), var(--cyan) 46%, rgba(53, 224, 232, 0) 90%);
}

.page-about .eyebrow {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-hero h1 {
  margin: 0 0 clamp(18px, 2.4vw, 26px);
  max-width: 22em;
  font-size: clamp(30px, 5.4vw, 64px);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: 0.02em;
  color: var(--white);
}

.page-about .hl {
  background: linear-gradient(100deg, var(--violet), var(--cyan));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.page-about .about-lede {
  max-width: 40em;
  margin: 0;
  font-size: clamp(15px, 1.4vw, 18px);
  line-height: 1.9;
  color: rgba(238, 241, 255, 0.82);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(122px, 1fr));
  gap: 20px 22px;
  margin: clamp(30px, 4vw, 48px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-facts li {
  padding-left: 14px;
  border-left: 2px solid rgba(164, 107, 255, 0.45);
}

.page-about .about-facts li:nth-child(2n) {
  border-left-color: rgba(53, 224, 232, 0.4);
}

.page-about .about-facts li:nth-child(3n) {
  border-left-color: rgba(243, 185, 74, 0.5);
}

.page-about .fact-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(19px, 2.1vw, 27px);
  line-height: 1.2;
  color: var(--cyan);
}

.page-about .fact-label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  line-height: 1.6;
  letter-spacing: 0.08em;
  color: var(--muted);
}

/* ---------- 主体两栏 ---------- */
.page-about .about-layout {
  display: grid;
  align-items: start;
  gap: var(--about-gap);
  padding-top: clamp(40px, 5.6vw, 84px);
  padding-bottom: clamp(56px, 7vw, 110px);
}

.page-about .about-rail {
  position: relative;
  top: auto;
  align-self: start;
  padding-top: 2px;
}

.page-about .rail-head {
  display: none;
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--muted);
}

.page-about .rail-list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 10px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .rail-list::-webkit-scrollbar {
  display: none;
}

.page-about .rail-list a {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 13px;
  white-space: nowrap;
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
  background: rgba(20, 26, 63, 0.7);
  border: 1px solid rgba(153, 162, 201, 0.22);
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 0 100%);
  transition: color 0.25s var(--ease-out), border-color 0.25s var(--ease-out);
}

.page-about .rail-list a:hover,
.page-about .rail-list a:focus-visible {
  color: var(--white);
  border-color: var(--violet);
}

.page-about .rail-num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about .about-flow {
  min-width: 0;
}

/* ---------- 章节通用 ---------- */
.page-about .about-section + .about-section {
  margin-top: var(--about-sec-gap);
}

.page-about .about-sec-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: clamp(18px, 2.4vw, 30px);
}

.page-about .about-sec-num {
  flex: none;
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--cyan);
  border: 1px solid rgba(53, 224, 232, 0.4);
}

.page-about .about-sec-head h2 {
  margin: 0;
  font-size: clamp(22px, 3.2vw, 38px);
  font-weight: 800;
  line-height: 1.22;
  letter-spacing: 0.02em;
}

.page-about .prose {
  max-width: 38em;
  font-size: clamp(15px, 1.1vw, 17px);
  line-height: 1.9;
  color: rgba(238, 241, 255, 0.84);
}

.page-about .prose p {
  margin: 0 0 1.05em;
}

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

.page-about .prose a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 224, 232, 0.42);
  transition: border-color 0.25s var(--ease-out);
}

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

/* ---------- 分类卡 ---------- */
.page-about .about-cats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(228px, 1fr));
  gap: 14px;
  margin-top: clamp(22px, 3vw, 34px);
}

.page-about .cat {
  position: relative;
  padding: 24px 20px 24px;
  background: linear-gradient(155deg, rgba(20, 26, 63, 0.96), rgba(43, 47, 122, 0.4));
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%);
}

.page-about .cat::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 24px;
  height: 3px;
  background: var(--violet);
}

.page-about .cat:nth-child(3n + 2)::before {
  background: var(--cyan);
}

.page-about .cat:nth-child(3n)::before {
  background: var(--gold);
}

.page-about .cat h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--white);
}

.page-about .cat p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-structure-note {
  margin-top: clamp(22px, 3vw, 32px);
}

/* ---------- 会员五档 ---------- */
.page-about .member-track {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(128px, 1fr));
  gap: 12px;
  margin: clamp(22px, 3vw, 32px) 0 clamp(24px, 3.2vw, 36px);
  padding: 0;
  list-style: none;
}

.page-about .tier {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 14px 18px;
  background: rgba(20, 26, 63, 0.74);
  border-top: 3px solid var(--muted);
  clip-path: polygon(0 0, calc(100% - 14px) 0, 100% 14px, 100% 100%, 0 100%);
}

.page-about .tier-1 { border-top-color: rgba(153, 162, 201, 0.6); }
.page-about .tier-2 { border-top-color: var(--cyan); }
.page-about .tier-3 { border-top-color: #8E7BFF; }
.page-about .tier-4 { border-top-color: var(--violet); }
.page-about .tier-5 { border-top-color: var(--gold); }

.page-about .tier-idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--muted);
}

.page-about .tier strong {
  font-size: 17px;
  letter-spacing: 0.06em;
  color: var(--white);
}

.page-about .tier-note {
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .about-member-fig {
  margin: 0 0 clamp(22px, 3vw, 32px);
}

/* ---------- 团队 ---------- */
.page-about .about-team-wrap {
  display: grid;
  gap: clamp(24px, 3.5vw, 48px);
  align-items: start;
}

.page-about .about-team {
  display: grid;
  gap: 22px;
  margin: clamp(22px, 3vw, 32px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .team-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 6px 12px;
  align-items: baseline;
}

.page-about .team-name {
  font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--white);
}

.page-about .team-count {
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--cyan);
}

.page-about .team-bar {
  position: relative;
  grid-column: 1 / -1;
  height: 8px;
  background: rgba(153, 162, 201, 0.14);
  overflow: hidden;
}

.page-about .team-bar i {
  position: absolute;
  inset: 0 auto 0 0;
  display: block;
  background: linear-gradient(90deg, var(--violet), var(--cyan));
}

.page-about .team-row--plan .team-bar i { width: 39%; }
.page-about .team-row--design .team-bar i { width: 25%; background: linear-gradient(90deg, var(--cyan), #6FD9FF); }
.page-about .team-row--tech .team-bar i { width: 22%; background: linear-gradient(90deg, #6E77C8, var(--violet)); }
.page-about .team-row--service .team-bar i { width: 14%; background: linear-gradient(90deg, var(--gold), rgba(243, 185, 74, 0.45)); }

.page-about .team-desc {
  grid-column: 1 / -1;
  font-size: 12.5px;
  line-height: 1.75;
  color: var(--muted);
  transition: color 0.3s var(--ease-out);
}

.page-about .team-row:hover .team-desc {
  color: rgba(238, 241, 255, 0.92);
}

.page-about .about-team-fig {
  margin: 0;
}

.page-about .about-team-note {
  margin-top: clamp(24px, 3.2vw, 38px);
}

/* ---------- 版本演进 ---------- */
.page-about .about-versions-banner {
  position: relative;
  height: clamp(150px, 21vw, 290px);
  margin-bottom: clamp(18px, 2.4vw, 28px);
  overflow: hidden;
  clip-path: polygon(0 0, calc(100% - 26px) 0, 100% 26px, 100% 100%, 0 100%);
}

.page-about .about-versions-banner img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.7;
}

.page-about .about-versions-banner::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(10, 15, 44, 0.35), rgba(10, 15, 44, 0.85));
  pointer-events: none;
}

.page-about .about-spark {
  display: block;
  width: 100%;
  height: auto;
  max-height: 150px;
}

.page-about .about-spark-note {
  margin: 6px 0 clamp(20px, 2.6vw, 30px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .about-versions {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .version-item {
  padding: 0 18px;
  background: rgba(20, 26, 63, 0.6);
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 0 100%);
}

.page-about .version-head {
  margin: 0;
  font-size: inherit;
  font-weight: inherit;
}

.page-about .version-item .accordion-trigger {
  display: grid;
  grid-template-columns: auto auto 1fr auto;
  grid-template-areas: "year tag title caret";
  align-items: center;
  gap: 10px 14px;
  width: 100%;
  padding: 16px 0;
  background: none;
  border: 0;
  color: var(--white);
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.page-about .version-item .accordion-trigger:hover .ver-title {
  color: var(--cyan);
}

.page-about .ver-year {
  grid-area: year;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .ver-tag {
  grid-area: tag;
  padding: 2px 7px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--cyan);
  border: 1px solid rgba(53, 224, 232, 0.38);
}

.page-about .ver-title {
  grid-area: title;
  font-size: 15.5px;
  letter-spacing: 0.02em;
  transition: color 0.25s var(--ease-out);
}

.page-about .ver-caret {
  grid-area: caret;
  justify-self: end;
  width: 9px;
  height: 9px;
  border-right: 2px solid var(--muted);
  border-bottom: 2px solid var(--muted);
  transform: rotate(45deg);
  transition: transform 0.3s var(--ease-out), border-color 0.3s var(--ease-out);
}

.page-about .version-item .accordion-trigger[aria-expanded="true"] .ver-caret {
  transform: rotate(-135deg);
  border-color: var(--cyan);
}

.page-about .version-item .accordion-panel {
  max-width: 42em;
  padding: 0 0 18px;
  font-size: 14.5px;
  line-height: 1.85;
  color: rgba(238, 241, 255, 0.8);
}

.page-about .version-item .accordion-panel p {
  margin: 0;
}

.page-about .about-versions-note {
  margin-top: clamp(22px, 3vw, 32px);
}

/* ---------- 品质把关 ---------- */
.page-about .q-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(148px, 1fr));
  gap: 16px 16px;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .q-step {
  padding-top: 14px;
  border-top: 1px solid rgba(153, 162, 201, 0.24);
  transition: border-color 0.3s var(--ease-out);
}

.page-about .q-step:hover {
  border-top-color: var(--violet);
}

.page-about .q-step b {
  display: block;
  margin-bottom: 7px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .q-name {
  display: block;
  margin-bottom: 5px;
  font-size: 15px;
  color: var(--white);
}

.page-about .q-step p {
  margin: 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 结尾入口 ---------- */
.page-about .about-next {
  margin-top: var(--about-sec-gap);
  padding: clamp(28px, 4vw, 52px);
  background: linear-gradient(120deg, rgba(164, 107, 255, 0.2), rgba(53, 224, 232, 0.1) 58%, rgba(243, 185, 74, 0.06));
  clip-path: polygon(0 0, calc(100% - 28px) 0, 100% 28px, 100% 100%, 0 100%);
}

.page-about .about-next h2 {
  margin: 0 0 14px;
  font-size: clamp(21px, 2.8vw, 30px);
  line-height: 1.3;
}

.page-about .about-next-lede {
  max-width: 42em;
  margin: 0 0 clamp(22px, 3vw, 32px);
  font-size: clamp(14.5px, 1.1vw, 16.5px);
  line-height: 1.9;
  color: rgba(238, 241, 255, 0.84);
}

.page-about .about-next-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 图片容器适配 ---------- */
.page-about .media img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .media-caption {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--muted);
}

/* ---------- 响应式 ---------- */
@media (min-width: 900px) {
  .page-about .about-team-wrap {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.82fr);
  }
}

@media (min-width: 1040px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
  }

  .page-about .about-rail {
    position: sticky;
    top: var(--rail-top);
    max-height: calc(100vh - var(--rail-top) - 32px);
    overflow-y: auto;
  }

  .page-about .rail-head {
    display: block;
  }

  .page-about .rail-list {
    flex-direction: column;
    gap: 2px;
    padding-bottom: 0;
    overflow: visible;
  }

  .page-about .rail-list a {
    width: 100%;
    padding: 9px 10px 9px 13px;
    background: none;
    border: 0;
    border-left: 2px solid rgba(153, 162, 201, 0.2);
    clip-path: none;
  }

  .page-about .rail-list a:hover,
  .page-about .rail-list a:focus-visible {
    border-left-color: var(--violet);
    background: linear-gradient(90deg, rgba(164, 107, 255, 0.16), rgba(164, 107, 255, 0));
  }
}

@media (max-width: 640px) {
  .page-about .version-item .accordion-trigger {
    grid-template-columns: auto 1fr auto;
    grid-template-areas:
      "year tag caret"
      "title title title";
    gap: 8px 12px;
    padding: 15px 0;
  }

  .page-about .about-versions-banner {
    height: 150px;
  }

  .page-about .about-spark {
    max-height: 96px;
  }

  .page-about .about-next-links .btn {
    width: 100%;
    text-align: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .rail-list a,
  .page-about .team-desc,
  .page-about .ver-caret,
  .page-about .ver-title,
  .page-about .q-step,
  .page-about .prose a {
    transition: none;
  }
}