.page-about {
  --about-axis-w: 176px;
  --about-num: clamp(52px, 10vw, 92px);
  --about-gap: clamp(28px, 4.5vw, 60px);
}

.page-about .breadcrumb {
  margin: 18px 0 22px;
}

/* ---------- 首屏：左叙事 / 右主题视觉 ---------- */
.page-about .about-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  align-items: center;
  padding-bottom: clamp(32px, 6vw, 64px);
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
  }
}

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

.page-about .about-hero__lead h1 {
  margin: 10px 0 18px;
  font-size: clamp(30px, 4.8vw, 46px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-hero__lead .lede {
  max-width: 62ch;
}

.page-about .about-hero__note {
  margin: 16px 0 0;
  max-width: 62ch;
  font-size: var(--t-14);
  line-height: 1.72;
  color: var(--muted);
  border-left: 3px solid rgba(124, 92, 255, 0.55);
  padding-left: 14px;
}

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

.page-about .about-hero__visual {
  margin: 0;
}

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

/* ---------- 长卷外壳：左侧章节轴 + 右侧正文 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  padding-top: clamp(26px, 5vw, 54px);
}

@media (min-width: 1024px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-axis-w) minmax(0, 1fr);
    gap: var(--about-gap);
  }
}

.page-about .about-axis__caption {
  margin: 0 0 10px;
  font-family: var(--f-mono);
  font-size: var(--t-12);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-axis__list {
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  display: flex;
  gap: 10px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-axis__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-left: 3px solid rgba(124, 92, 255, 0.65);
  background: rgba(16, 42, 62, 0.42);
  color: var(--muted);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease), background 0.25s var(--ease);
}

.page-about .about-axis__num {
  font-family: var(--f-mono);
  font-size: var(--t-12);
  color: var(--violet);
}

.page-about .about-axis__text {
  font-size: var(--t-14);
}

.page-about .about-axis__link:hover,
.page-about .about-axis__link[aria-current] {
  color: var(--paper);
  border-left-color: var(--cyan);
  background: rgba(0, 229, 208, 0.09);
}

@media (min-width: 1024px) {
  .page-about .about-axis {
    position: sticky;
    top: 28px;
    align-self: start;
  }

  .page-about .about-axis__list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
  }

  .page-about .about-axis__link {
    border: 0;
    border-left: 3px solid var(--line);
    background: none;
    padding: 7px 0 7px 12px;
  }

  .page-about .about-axis__link:hover,
  .page-about .about-axis__link[aria-current] {
    background: none;
    border-left-color: var(--cyan);
  }
}

.page-about .about-flow {
  display: flex;
  flex-direction: column;
  gap: clamp(38px, 6vw, 76px);
  min-width: 0;
}

/* ---------- 章节 ---------- */
.page-about .chap {
  min-width: 0;
  border-top: 2px solid rgba(124, 92, 255, 0.28);
  padding-top: clamp(20px, 3vw, 32px);
}

.page-about .chap__head {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 20px;
}

.page-about .chap__num {
  display: inline-block;
  align-self: flex-start;
  font-family: var(--f-mono);
  font-weight: 700;
  font-size: var(--about-num);
  line-height: 0.92;
  letter-spacing: -0.05em;
  color: var(--paper);
  padding: 4px 22px 12px 16px;
  border-left: 6px solid var(--violet);
  background: linear-gradient(90deg, rgba(124, 92, 255, 0.34), rgba(124, 92, 255, 0.02));
}

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

.page-about .chap__body p {
  margin: 0 0 14px;
  max-width: 68ch;
  font-size: var(--t-16);
  line-height: 1.75;
  color: var(--paper);
}

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

.page-about .inline-link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 229, 208, 0.42);
}

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

.page-about .data-strip {
  margin-top: 24px;
}

/* ---------- 四个方向 ---------- */
.page-about .pillars {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 24px 0 26px;
}

@media (min-width: 720px) {
  .page-about .pillars {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .pillar {
  min-width: 0;
  padding: 20px 20px 22px;
  background: rgba(16, 42, 62, 0.55);
  border: 1px solid var(--line);
  border-top: 3px solid var(--cyan);
  transition: transform 0.28s var(--ease), border-color 0.28s var(--ease);
}

.page-about .pillar:nth-child(1) {
  border-top-color: rgba(0, 229, 208, 0.6);
}

.page-about .pillar:nth-child(2) {
  border-top-color: rgba(255, 179, 58, 0.6);
}

.page-about .pillar:nth-child(3) {
  border-top-color: rgba(255, 46, 136, 0.6);
}

.page-about .pillar:nth-child(4) {
  border-top-color: rgba(124, 92, 255, 0.6);
}

.page-about .pillar:hover {
  transform: translateY(-4px);
  border-color: var(--cyan);
}

.page-about .pillar h3 {
  margin: 12px 0 8px;
  font-size: var(--t-20);
  line-height: 1.35;
  color: var(--paper);
}

.page-about .pillar p {
  margin: 0;
  font-size: var(--t-14);
  line-height: 1.72;
  color: var(--muted);
}

/* ---------- 指标定义 ---------- */
.page-about .metrics-block {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  margin-top: 22px;
}

@media (min-width: 900px) {
  .page-about .metrics-block {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 1fr);
    gap: clamp(20px, 3vw, 42px);
    align-items: start;
  }
}

.page-about .metrics {
  border-bottom: 1px solid var(--line);
}

.page-about .metrics .metric {
  border-top: 1px solid var(--line);
}

.page-about .metrics .fold-summary {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 14px;
  padding: 15px 2px;
  cursor: pointer;
  font-size: var(--t-16);
  color: var(--paper);
}

.page-about .metric__term {
  font-size: var(--t-16);
  color: var(--paper);
}

.page-about .metric__tag {
  flex: 0 0 auto;
  font-family: var(--f-mono);
  font-size: var(--t-12);
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .metric__tag::after {
  content: " +";
  color: var(--cyan);
}

.page-about .metric[open] .metric__tag::after {
  content: " –";
}

.page-about .metrics .fold-content {
  padding: 0 2px 16px;
}

.page-about .metrics .fold-content p {
  margin: 0 0 10px;
  max-width: 62ch;
  font-size: var(--t-14);
  line-height: 1.72;
  color: var(--muted);
}

.page-about .metric__demo {
  font-family: var(--f-mono);
  font-size: var(--t-14);
  color: var(--cyan-soft);
  border-left: 3px solid rgba(0, 229, 208, 0.45);
  padding-left: 12px;
}

.page-about .metrics__figure {
  margin: 0;
  padding: 18px;
  border: 1px solid var(--line);
  background: rgba(5, 11, 20, 0.6);
}

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

.page-about .metrics__figure figcaption {
  margin-top: 14px;
  font-size: var(--t-12);
  line-height: 1.7;
  letter-spacing: 0.03em;
  color: var(--muted);
}

/* ---------- 团队与流程 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
  margin-bottom: 28px;
}

@media (min-width: 900px) {
  .page-about .team-grid {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
    gap: clamp(24px, 3vw, 44px);
    align-items: start;
  }
}

.page-about .team-figure,
.page-about .timeline-figure {
  margin: 0;
}

.page-about .team-figure img,
.page-about .timeline-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .proc {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

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

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

.page-about .proc__step {
  position: relative;
  min-width: 0;
  padding: 20px 16px 22px;
  background: linear-gradient(180deg, rgba(16, 42, 62, 0.9), rgba(11, 26, 43, 0.72));
  border: 1px solid var(--line);
  transition: border-color 0.28s var(--ease), transform 0.28s var(--ease);
}

.page-about .proc__step::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--cyan), rgba(0, 229, 208, 0));
}

.page-about .proc__step:nth-child(2)::before {
  background: linear-gradient(90deg, var(--violet), rgba(124, 92, 255, 0));
}

.page-about .proc__step:nth-child(3)::before {
  background: linear-gradient(90deg, var(--amber), rgba(255, 179, 58, 0));
}

.page-about .proc__step:nth-child(4)::before {
  background: linear-gradient(90deg, var(--magenta), rgba(255, 46, 136, 0));
}

.page-about .proc__step:hover {
  transform: translateY(-4px);
  border-color: var(--line-strong);
}

.page-about .proc__idx {
  display: inline-block;
  margin-bottom: 12px;
  padding: 2px 7px;
  font-family: var(--f-mono);
  font-size: var(--t-12);
  letter-spacing: 0.12em;
  color: var(--cyan);
  border: 1px solid rgba(0, 229, 208, 0.4);
}

.page-about .proc__step h3 {
  margin: 0 0 8px;
  font-size: var(--t-20);
  color: var(--paper);
}

.page-about .proc__step p {
  margin: 0;
  font-size: var(--t-14);
  line-height: 1.72;
  color: var(--muted);
}

/* ---------- 版本演进时间线 ---------- */
.page-about .timeline-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

@media (min-width: 900px) {
  .page-about .timeline-grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: clamp(24px, 4vw, 48px);
    align-items: start;
  }
}

.page-about .miles {
  list-style: none;
  margin: 8px 0 0;
  padding: 0 0 0 26px;
  border-left: 2px solid rgba(255, 179, 58, 0.35);
}

.page-about .mile {
  position: relative;
  padding-bottom: 26px;
  transition: transform 0.3s var(--ease);
}

.page-about .mile:last-child {
  padding-bottom: 4px;
}

.page-about .mile::before {
  content: "";
  position: absolute;
  left: -32px;
  top: 6px;
  width: 10px;
  height: 10px;
  transform: rotate(45deg);
  background: var(--amber);
  box-shadow: 0 0 0 4px rgba(255, 179, 58, 0.14);
}

.page-about .mile:hover {
  transform: translateX(4px);
}

.page-about .mile__year {
  display: inline-block;
  font-family: var(--f-mono);
  font-size: var(--t-20);
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--amber);
}

.page-about .mile h3 {
  margin: 6px 0 8px;
  font-size: var(--t-20);
  line-height: 1.35;
  color: var(--paper);
}

.page-about .mile p {
  margin: 0;
  max-width: 56ch;
  font-size: var(--t-14);
  line-height: 1.72;
  color: var(--muted);
}

/* ---------- 结尾导流 ---------- */
.page-about .about-next {
  margin-top: clamp(48px, 8vw, 96px);
  padding-bottom: clamp(40px, 7vw, 80px);
}

.page-about .about-next__inner {
  border: 1px solid rgba(124, 92, 255, 0.4);
  background: linear-gradient(135deg, rgba(124, 92, 255, 0.16), rgba(5, 11, 20, 0));
  padding: clamp(24px, 4vw, 44px);
}

.page-about .about-next__lede {
  margin: 14px 0 0;
  max-width: 62ch;
  font-size: var(--t-16);
  line-height: 1.75;
  color: var(--muted);
}

.page-about .next-links {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
}

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

.page-about .next-links a {
  display: block;
  padding: 14px 16px;
  border: 1px solid var(--line);
  color: var(--paper);
  font-size: var(--t-14);
  line-height: 1.6;
  text-decoration: none;
  transition: border-color 0.25s var(--ease), background 0.25s var(--ease), color 0.25s var(--ease);
}

.page-about .next-links a:hover {
  border-color: var(--cyan);
  background: rgba(0, 229, 208, 0.07);
  color: var(--cyan-soft);
}

/* ---------- 显现 ---------- */
.page-about [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}

.page-about [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .page-about .pillar:hover,
  .page-about .proc__step:hover,
  .page-about .mile:hover {
    transform: none;
  }
}