.page-about {
  --about-gap: clamp(20px, 4vw, 44px);
  --about-chapter-top: clamp(34px, 5vw, 66px);
}

/* 面包屑 */
.page-about .breadcrumbs {
  padding-top: clamp(16px, 3vw, 30px);
}

.page-about .breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .04em;
}

.page-about .breadcrumbs li {
  display: inline-flex;
  align-items: center;
  color: var(--text-3);
}

.page-about .breadcrumbs li + li::before {
  content: "/";
  margin: 0 10px;
  color: var(--text-3);
}

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

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

/* 首屏分屏 */
.page-about .about-hero {
  padding-top: clamp(22px, 4vw, 42px);
  padding-bottom: clamp(34px, 6vw, 76px);
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(28px, 5vw, 56px);
  align-items: center;
}

.page-about .about-hero-copy h1 {
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: -.015em;
  line-height: 1.14;
  font-size: clamp(29px, 5.4vw, 52px);
  margin: 12px 0 20px;
  color: var(--text);
}

.page-about .about-hero-meta {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
  border-top: 1px solid var(--line-soft);
  padding-top: 20px;
}

.page-about .about-hero-meta li {
  font-size: 14px;
  color: var(--text-2);
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
}

.page-about .about-hero-meta .mono {
  font-family: var(--font-mono);
  color: var(--cyan);
  font-size: 13px;
  letter-spacing: .06em;
  border-left: 2px solid var(--coral);
  padding-left: 8px;
}

/* 首屏右侧纯 CSS 数据视觉 */
.page-about .about-hero-visual {
  position: relative;
}

.page-about .ahv-frame {
  position: relative;
  border: 1px solid var(--line);
  background: linear-gradient(152deg, var(--ink-1) 0%, var(--ink-0) 72%);
  padding: clamp(16px, 3vw, 26px);
  box-shadow: var(--shadow-card);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 28px), calc(100% - 28px) 100%, 0 100%);
}

.page-about .ahv-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--line-soft) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line-soft) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: .5;
  pointer-events: none;
}

.page-about .ahv-head {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .ahv-dot {
  width: 8px;
  height: 8px;
  background: var(--line);
  display: block;
}

.page-about .ahv-dot--coral {
  background: var(--coral);
}

.page-about .ahv-title {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--text-2);
}

.page-about .ahv-bars {
  position: relative;
  display: flex;
  align-items: flex-end;
  gap: 6px;
  height: clamp(130px, 22vw, 190px);
  margin-top: 22px;
  padding-bottom: 1px;
  border-bottom: 1px solid var(--line);
}

.page-about .ahv-bars span {
  flex: 1 1 0;
  min-width: 0;
  display: block;
  background: linear-gradient(180deg, var(--cyan) 0%, rgba(64, 240, 208, .12) 100%);
}

.page-about .ahv-bars span:nth-child(1) { height: 34%; }
.page-about .ahv-bars span:nth-child(2) { height: 58%; }
.page-about .ahv-bars span:nth-child(3) { height: 44%; }
.page-about .ahv-bars span:nth-child(4) { height: 76%; background: linear-gradient(180deg, var(--coral) 0%, rgba(255, 106, 77, .12) 100%); }
.page-about .ahv-bars span:nth-child(5) { height: 52%; }
.page-about .ahv-bars span:nth-child(6) { height: 86%; }
.page-about .ahv-bars span:nth-child(7) { height: 40%; }
.page-about .ahv-bars span:nth-child(8) { height: 68%; background: linear-gradient(180deg, var(--coral) 0%, rgba(255, 106, 77, .12) 100%); }
.page-about .ahv-bars span:nth-child(9) { height: 57%; }
.page-about .ahv-bars span:nth-child(10) { height: 92%; }
.page-about .ahv-bars span:nth-child(11) { height: 63%; }
.page-about .ahv-bars span:nth-child(12) { height: 80%; }

.page-about .ahv-foot {
  position: relative;
  display: flex;
  justify-content: space-between;
  margin-top: 14px;
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--text-3);
}

.page-about .ahv-foot-coral {
  color: var(--coral-soft);
}

/* 章节骨架 */
.page-about .about-chapter {
  display: grid;
  gap: 16px;
  padding-top: var(--about-chapter-top);
  padding-bottom: var(--about-chapter-top);
  margin-top: var(--about-chapter-top);
  border-top: 1px solid var(--line-soft);
}

.page-about .about-chapter-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(38px, 9vw, 58px);
  line-height: .86;
  letter-spacing: -.03em;
  color: var(--cyan);
  opacity: .9;
}

.page-about .about-chapter-body > .section-title {
  margin-bottom: 14px;
}

.page-about .about-chapter-body > .lead {
  margin-bottom: 26px;
  max-width: 62ch;
}

/* 双栏文本 */
.page-about .about-duo {
  display: grid;
  gap: clamp(20px, 3vw, 34px);
}

.page-about .about-duo-col p {
  margin: 0 0 16px;
  color: var(--text-2);
  line-height: 1.78;
}

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

/* 数据链路 */
.page-about .about-chain-grid {
  display: grid;
  gap: clamp(26px, 4vw, 46px);
}

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

.page-about .about-flow-step {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 14px;
  padding: 20px 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-flow-step:last-child {
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-flow-idx {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--coral);
  padding-top: 4px;
}

.page-about .about-flow-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.4;
  margin: 0 0 8px;
  color: var(--text);
}

.page-about .about-flow-step p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-2);
}

/* 图片 */
.page-about .about-figure {
  margin: 0;
}

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

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .05em;
  color: var(--text-3);
}

.page-about .about-figure--band {
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .about-figure--band img {
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 34px), calc(100% - 34px) 100%, 0 100%);
}

/* 里程碑轴 */
.page-about .about-timeline {
  list-style: none;
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(232px, 1fr);
  gap: 0;
  margin: 0;
  padding: 22px 0 18px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  -webkit-overflow-scrolling: touch;
}

.page-about .about-timeline::-webkit-scrollbar {
  height: 4px;
}

.page-about .about-timeline::-webkit-scrollbar-thumb {
  background: var(--cyan);
}

.page-about .about-node {
  position: relative;
  scroll-snap-align: start;
  padding: 18px 20px 6px 0;
  margin-right: 20px;
  border-right: 1px solid var(--line-soft);
}

.page-about .about-node:last-child {
  border-right: 0;
  margin-right: 0;
  padding-right: 0;
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  top: -27px;
  left: 0;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--coral);
  box-shadow: 0 0 0 5px rgba(255, 106, 77, .14);
}

.page-about .about-node-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--cyan);
  margin-bottom: 10px;
}

.page-about .about-node-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  line-height: 1.35;
  margin: 0 0 8px;
  color: var(--text);
}

.page-about .about-node p {
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--text-2);
  max-width: 30ch;
}

/* 版本演进补充区 */
.page-about .about-evolve {
  display: grid;
  gap: clamp(22px, 4vw, 40px);
  margin-top: clamp(28px, 4vw, 46px);
}

.page-about .about-evolve-copy p {
  color: var(--text-2);
  line-height: 1.78;
  margin: 0 0 14px;
}

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

.page-about .about-evolve-copy .about-node-title {
  margin-bottom: 12px;
}

/* 原则折叠 */
.page-about .about-rules {
  display: grid;
  gap: 12px;
}

.page-about .about-rule {
  background: linear-gradient(100deg, rgba(18, 70, 111, .38) 0%, rgba(4, 16, 31, .5) 100%);
  border-left: 2px solid var(--cyan);
  transition: border-color .2s ease;
}

.page-about .about-rule[open] {
  border-left-color: var(--coral);
}

.page-about .about-rule-idx {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--coral);
  margin-right: 12px;
}

.page-about .about-rule .fold-body p {
  margin: 0;
  color: var(--text-2);
  line-height: 1.78;
}

/* 合作生态 */
.page-about .about-partners {
  display: grid;
  gap: clamp(20px, 3vw, 30px);
}

.page-about .about-partner {
  border-top: 2px solid var(--cyan);
  padding-top: 16px;
}

.page-about .about-partner:nth-child(2) {
  border-top-color: var(--coral);
}

.page-about .about-partner:nth-child(3) {
  border-top-color: var(--cyan-soft);
}

.page-about .about-partner-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  margin: 0 0 10px;
  color: var(--text);
}

.page-about .about-partner p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-2);
}

.page-about .about-partner a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(64, 240, 208, .4);
}

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

.page-about .about-report {
  margin: clamp(24px, 4vw, 36px) 0 0;
  padding-left: 18px;
  border-left: 2px solid var(--coral);
  color: var(--text-2);
  line-height: 1.78;
}

/* 结尾行动区 */
.page-about .about-cta-wrap {
  padding-bottom: clamp(40px, 7vw, 88px);
}

.page-about .about-cta {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  background: linear-gradient(118deg, var(--ink-1) 0%, var(--ink-0) 68%);
  padding: clamp(26px, 5vw, 52px);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 32px), calc(100% - 32px) 100%, 0 100%);
}

.page-about .about-cta::after {
  content: "";
  position: absolute;
  right: -90px;
  bottom: -140px;
  width: 360px;
  height: 360px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(64, 240, 208, .22) 0%, transparent 68%);
  pointer-events: none;
}

.page-about .about-cta-title {
  position: relative;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(22px, 3.6vw, 32px);
  line-height: 1.24;
  margin: 10px 0 14px;
  color: var(--text);
}

.page-about .about-cta-text {
  position: relative;
  margin: 0 0 26px;
  max-width: 58ch;
  color: var(--text-2);
  line-height: 1.78;
}

.page-about .about-cta-actions {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

/* 平板及以上 */
@media (min-width: 620px) {
  .page-about .about-partners {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .about-duo {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .page-about .about-duo-col + .about-duo-col {
    border-left: 1px solid var(--line-soft);
    padding-left: clamp(20px, 3vw, 34px);
  }
}

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: 1.08fr .92fr;
    align-items: center;
  }

  .page-about .about-chapter {
    grid-template-columns: 128px minmax(0, 1fr);
    gap: clamp(24px, 4vw, 56px);
  }

  .page-about .about-chapter-num {
    position: sticky;
    top: 112px;
    align-self: start;
  }

  .page-about .about-chain-grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    align-items: start;
  }

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

  .page-about .about-cta-text {
    margin-bottom: 32px;
  }
}

@media (min-width: 1080px) {
  .page-about .about-timeline {
    grid-auto-columns: minmax(260px, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    animation: none !important;
    transition: none !important;
  }
}