.page-about {
  --about-rail: 128px;
  --about-shadow: 10px 10px 0 -1px rgba(82, 122, 111, 0.16),
                  0 34px 70px -48px rgba(0, 0, 0, 0.92);
  --about-paper: linear-gradient(165deg, rgba(20, 60, 48, 0.84) 0%, rgba(14, 42, 34, 0.92) 55%, rgba(11, 15, 14, 0.95) 100%);
  position: relative;
  display: block;
  background:
    radial-gradient(120% 55% at 86% -8%, rgba(71, 245, 210, 0.10), transparent 62%),
    radial-gradient(95% 46% at 2% 18%, rgba(255, 138, 61, 0.07), transparent 58%),
    var(--carbon);
  color: var(--mist);
  overflow-x: clip;
}

.page-about .about-wrap {
  padding-top: calc(var(--yb-header-h) + clamp(1.5rem, 4vw, 3rem));
  padding-bottom: clamp(3rem, 8vw, 5.5rem);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  display: grid;
  gap: clamp(1.75rem, 4vw, 3rem);
  padding-bottom: clamp(2.5rem, 6vw, 4.5rem);
  border-bottom: 1px solid var(--edge-soft);
}

.page-about .about-hero__lede h1 {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(2.25rem, 6.4vw, 4.25rem);
  line-height: 1.14;
  letter-spacing: -0.01em;
  margin: 0.7rem 0 1.1rem;
  color: var(--mist);
  text-wrap: balance;
}

.page-about .about-hero__lead {
  max-width: 48ch;
  margin: 0;
  font-size: clamp(1rem, 1.6vw, 1.125rem);
  line-height: 1.9;
  color: var(--ash);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.75rem;
}

.page-about .about-hero__stack {
  display: grid;
  gap: 1rem;
  align-content: start;
}

.page-about .about-slip {
  position: relative;
  padding: 1.2rem 1.3rem 1.3rem;
  border: 1px solid var(--edge-soft);
  border-radius: var(--yb-radius-s);
  background: var(--about-paper);
  box-shadow: var(--about-shadow);
  transition: border-color 0.3s ease, transform 0.3s ease;
}

.page-about .about-slip:hover {
  border-color: var(--edge-strong);
  transform: translateY(-3px);
}

.page-about .about-slip--cyan {
  border-color: rgba(71, 245, 210, 0.38);
}

.page-about .about-slip--orange {
  border-color: rgba(255, 138, 61, 0.38);
}

.page-about .about-slip__k {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ash);
}

.page-about .about-slip__v {
  margin: 0.45rem 0 0.35rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.9rem, 4.4vw, 2.6rem);
  line-height: 1.05;
  color: var(--mist);
  font-variant-numeric: tabular-nums;
}

.page-about .about-slip__v span {
  font-size: 0.85rem;
  font-weight: 400;
  margin-left: 0.3rem;
  color: var(--ash);
}

.page-about .about-slip--cyan .about-slip__v { color: var(--cyan); }
.page-about .about-slip--orange .about-slip__v { color: var(--orange); }

.page-about .about-slip__n {
  margin: 0;
  font-size: 0.86rem;
  line-height: 1.65;
  color: var(--ash);
}

/* ---------- 章节骨架：左侧年份轴 ---------- */

.page-about .about-chapter {
  display: grid;
  gap: clamp(1.25rem, 3vw, 2.25rem);
  padding: clamp(2.75rem, 7vw, 5rem) 0;
  border-bottom: 1px solid var(--edge-soft);
}

.page-about .about-rail {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  padding-left: 1rem;
}

.page-about .about-rail::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.3rem;
  bottom: 0.3rem;
  width: 2px;
  border-radius: 2px;
  background: var(--edge-soft);
  transition: background 0.4s ease;
}

.page-about .about-rail__year {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.15rem, 3.4vw, 1.6rem);
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--line);
  text-decoration: none;
  font-variant-numeric: tabular-nums;
  transition: color 0.35s ease;
}

.page-about .about-rail__year:hover,
.page-about .about-rail__year:focus-visible {
  color: var(--cyan);
}

.page-about .about-rail__note {
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  color: var(--ash);
}

.page-about .about-chapter[data-current] .about-rail::before {
  background: linear-gradient(180deg, var(--cyan), rgba(71, 245, 210, 0.18));
}

.page-about .about-chapter[data-current] .about-rail__year {
  color: var(--cyan);
}

.page-about .about-body > p {
  max-width: 64ch;
  margin: 0 0 1.05rem;
  font-size: 1rem;
  line-height: 1.9;
  color: var(--ash);
}

.page-about .about-body h2.yb-section__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(1.6rem, 4vw, 2.6rem);
  line-height: 1.28;
  margin: 0.5rem 0 0.95rem;
  color: var(--mist);
  text-wrap: balance;
}

.page-about .about-body h3 {
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.5;
  margin: 0 0 0.6rem;
  color: var(--mist);
}

.page-about .about-body .yb-section__lead {
  max-width: 60ch;
  margin: 0 0 1.35rem;
  font-size: 1.05rem;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(71, 245, 210, 0.4);
  transition: border-color 0.25s ease, color 0.25s ease;
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--sheen);
  border-bottom-color: var(--sheen);
}

.page-about .about-note {
  margin-top: 1.75rem;
  padding: 1rem 1.15rem;
  border-left: 3px solid var(--orange);
  border-radius: 0 var(--yb-radius-s) var(--yb-radius-s) 0;
  background: var(--orange-ghost);
  color: var(--mist) !important;
  font-size: 0.94rem !important;
  line-height: 1.8 !important;
  max-width: 62ch;
}

/* ---------- 事实小列表 ---------- */

.page-about .about-facts {
  list-style: none;
  margin: 1.6rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.65rem;
}

.page-about .about-facts li {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  padding: 0.7rem 0.95rem;
  border: 1px dashed var(--edge-soft);
  border-radius: 10px;
  font-size: 0.94rem;
  line-height: 1.7;
  color: var(--ash);
}

.page-about .about-facts__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
  flex: 0 0 auto;
}

/* ---------- 图片 ---------- */

.page-about .yb-media {
  margin: 1.75rem 0;
  background: var(--deep);
  border: 1px solid var(--edge-soft);
  border-radius: var(--yb-radius);
  overflow: hidden;
}

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

.page-about .yb-media__cap {
  padding: 0.75rem 1.1rem 0.9rem;
  font-size: 0.84rem;
  line-height: 1.6;
  color: var(--ash);
  border-top: 1px solid var(--edge-soft);
}

/* ---------- 版本时间线 ---------- */

.page-about .about-timeline {
  display: grid;
  gap: 1rem;
  margin: 0.5rem 0 0;
}

.page-about .about-version {
  position: relative;
  padding: 1.4rem 1.3rem 1.35rem;
  border: 1px solid var(--edge-soft);
  border-radius: var(--yb-radius-s);
  background: var(--about-paper);
  box-shadow: 8px 8px 0 -1px rgba(82, 122, 111, 0.14);
  transition: transform 0.32s ease, border-color 0.32s ease;
}

.page-about .about-version:hover {
  transform: translateY(-4px);
  border-color: rgba(71, 245, 210, 0.48);
}

.page-about .about-version__year {
  margin: 0 0 0.55rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.35rem;
  letter-spacing: 0.06em;
  color: var(--orange);
  font-variant-numeric: tabular-nums;
}

.page-about .about-version h3 {
  color: var(--mist);
}

.page-about .about-version p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--ash);
}

/* ---------- 覆盖规模 ---------- */

.page-about .about-metrics {
  list-style: none;
  margin: 0 0 1.6rem;
  padding: 0;
  display: grid;
  gap: 1px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  background: var(--edge-soft);
  border: 1px solid var(--edge-soft);
  border-radius: var(--yb-radius-s);
  overflow: hidden;
}

.page-about .about-metrics__item {
  padding: 1.15rem 1rem 1.2rem;
  background: linear-gradient(170deg, rgba(14, 42, 34, 0.95), rgba(11, 15, 14, 0.98));
}

.page-about .about-metrics__value {
  margin: 0 0 0.35rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.5rem, 4.4vw, 2.1rem);
  line-height: 1.05;
  color: var(--mist);
  font-variant-numeric: tabular-nums;
}

.page-about .about-metrics__value span {
  font-size: 0.8rem;
  font-weight: 400;
  margin-left: 0.2rem;
  color: var(--ash);
}

.page-about .about-metrics__item--cyan .about-metrics__value { color: var(--cyan); }
.page-about .about-metrics__item--orange .about-metrics__value { color: var(--orange); }

.page-about .about-metrics__label {
  margin: 0;
  font-size: 0.82rem;
  line-height: 1.6;
  color: var(--ash);
}

/* ---------- 合作 ---------- */

.page-about .about-partners {
  margin: 0.4rem 0 1.75rem;
}

.page-about .about-partner {
  padding: 1.3rem 1.2rem 1.35rem;
  border-radius: var(--yb-radius-s);
}

.page-about .about-partner__n {
  margin: 0 0 0.5rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.7rem;
  line-height: 1;
  color: var(--orange);
  font-variant-numeric: tabular-nums;
}

.page-about .about-partner__t {
  font-size: 1rem;
  margin: 0 0 0.5rem;
  color: var(--mist);
}

.page-about .about-partner__d {
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.75;
  color: var(--ash);
}

.page-about .about-honors {
  list-style: none;
  margin: 0 0 1.6rem;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

/* ---------- 结尾行动区 ---------- */

.page-about .about-cta {
  margin-top: clamp(2.5rem, 7vw, 4.5rem);
  padding: clamp(1.75rem, 5vw, 3rem);
  border-radius: var(--yb-radius);
}

.page-about .about-cta h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 3.6vw, 2.25rem);
  line-height: 1.3;
  margin: 0.45rem 0 0.85rem;
  color: var(--mist);
  text-wrap: balance;
}

.page-about .about-cta p {
  max-width: 58ch;
  margin: 0 0 1.5rem;
  font-size: 0.98rem;
  line-height: 1.85;
  color: var(--ash);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-metrics {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .about-timeline {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-chapter {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(2rem, 4vw, 3.25rem);
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--yb-header-h) + 2rem);
    align-self: start;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.4rem;
    padding-left: 1.25rem;
    height: fit-content;
  }

  .page-about .about-rail::before {
    top: 0.25rem;
    bottom: 0.55rem;
  }

  .page-about .yb-media {
    margin: 2rem 0;
  }

  .page-about .about-media--aside {
    max-width: 560px;
  }

  .page-about .about-media--inline {
    max-width: 520px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-hero__stack {
    margin-top: 3.5rem;
  }

  .page-about .about-slip:nth-child(2) {
    margin-left: 1.25rem;
  }

  .page-about .about-slip:nth-child(3) {
    margin-left: 0.5rem;
  }
}