.page-about {
  --about-line: rgba(239, 230, 214, 0.20);
  --about-year-fill: rgba(239, 230, 214, 0.10);
  --about-year-stroke: rgba(239, 230, 214, 0.32);
  --about-shadow: rgba(58, 21, 18, 0.55);
  padding-bottom: 4rem;
}

.page-about .breadcrumb {
  margin-top: 1.25rem;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 1.75rem;
  margin-top: 1.25rem;
}

.page-about .about-hero__shot {
  margin: 0;
  overflow: hidden;
  aspect-ratio: 4 / 3;
  border: 1px solid var(--line-strong);
  background: var(--obsidian-soft);
  box-shadow: 10px 12px 0 var(--about-shadow);
}

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

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

.page-about .about-hero h1 {
  margin: 0;
  font-family: var(--font-head);
  font-size: clamp(1.875rem, 7vw, 3.5rem);
  line-height: 1.08;
  letter-spacing: -0.025em;
  font-weight: 800;
  color: var(--snow);
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 38rem;
  font-size: 1rem;
  line-height: 1.78;
  color: var(--fg-mute);
}

.page-about .about-hero__key {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.9rem 1.25rem;
  margin: 0;
  padding: 1.1rem 0 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .about-hero__key li {
  display: grid;
  gap: 0.15rem;
}

.page-about .about-hero__key .mono {
  font-size: 1.5rem;
  letter-spacing: -0.02em;
  color: var(--snow);
}

.page-about .about-hero__key span:last-child {
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  color: var(--slate);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-shell {
  display: grid;
  gap: 2.25rem;
  margin-top: 3.5rem;
}

.page-about .about-rail__nav {
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  padding-bottom: 0.5rem;
  scrollbar-width: thin;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 0.45rem;
  flex: 0 0 auto;
  padding: 0.5rem 0.75rem;
  border-left: 2px solid var(--line);
  color: var(--fg-mute);
  font-size: 0.8125rem;
  letter-spacing: 0.05em;
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s var(--ease-stand), border-color 0.2s var(--ease-stand);
}

.page-about .about-rail__link .mono {
  font-size: 0.75rem;
  color: var(--ochre);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--snow);
  border-left-color: var(--ochre);
}

.page-about .about-flow {
  display: flex;
  flex-direction: column;
  gap: 3.5rem;
  min-width: 0;
}

/* ---------- 年份段落 ---------- */
.page-about .era {
  position: relative;
  display: grid;
  gap: 1rem;
  padding-left: 1.5rem;
  border-left: 1px solid var(--about-line);
}

.page-about .era::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 0.9rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ochre);
  box-shadow: 0 0 0 4px rgba(192, 138, 46, 0.16);
}

.page-about .era__year {
  font-size: clamp(3.25rem, 15vw, 5.5rem);
  line-height: 0.82;
  letter-spacing: -0.05em;
  font-weight: 700;
  color: var(--about-year-fill);
  -webkit-text-stroke: 1px var(--about-year-stroke);
  user-select: none;
}

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

.page-about .era__title {
  margin: 0 0 0.9rem;
  font-size: clamp(1.375rem, 4.6vw, 2rem);
  line-height: 1.25;
  letter-spacing: -0.015em;
  font-weight: 800;
  color: var(--snow);
}

.page-about .era__lead {
  margin: 0 0 0.5rem;
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--ochre);
  letter-spacing: 0.02em;
}

.page-about .era .prose p {
  margin: 0 0 1rem;
  max-width: 38rem;
  font-size: 1rem;
  line-height: 1.78;
  color: var(--fg-mute);
}

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

.page-about .era__link {
  margin: 1.5rem 0 0;
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  display: grid;
  gap: 0.65rem;
  margin: 1.5rem 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 10 / 7;
  object-fit: cover;
  border: 1px solid var(--line-strong);
  box-shadow: 8px 10px 0 var(--about-shadow);
}

.page-about .about-figure figcaption,
.page-about .about-banner figcaption,
.page-about .steps figcaption {
  font-size: 0.8125rem;
  line-height: 1.65;
  letter-spacing: 0.03em;
  color: var(--slate);
}

.page-about .about-banner {
  display: grid;
  gap: 0.75rem;
  margin: 0;
}

.page-about .about-banner img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 8 / 3;
  object-fit: cover;
  border: 1px solid var(--line-strong);
  box-shadow: 12px 14px 0 var(--about-shadow);
}

/* ---------- 版本分段切换 ---------- */
.page-about .tabs {
  margin-top: 1.25rem;
}

.page-about .segmented {
  display: flex;
  gap: 0.375rem;
  overflow-x: auto;
  padding-bottom: 0.65rem;
  border-bottom: 1px solid var(--line);
  scrollbar-width: thin;
}

.page-about .segmented__btn {
  flex: 0 0 auto;
  appearance: none;
  padding: 0.5rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: transparent;
  color: var(--fg-mute);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: color 0.2s var(--ease-stand), border-color 0.2s var(--ease-stand), background-color 0.2s var(--ease-stand);
}

.page-about .segmented__btn:hover {
  color: var(--snow);
  border-color: var(--line-strong);
}

.page-about .segmented__btn[aria-selected="true"] {
  background: var(--milan-red);
  border-color: var(--milan-red);
  color: var(--snow);
}

.page-about .segmented__btn:focus-visible {
  outline: 2px solid var(--ochre);
  outline-offset: 2px;
}

.page-about .tabs__panels {
  margin-top: 1.5rem;
}

.page-about .tabs__panel {
  max-width: 44rem;
  padding-left: 1.05rem;
}

.page-about .tabs__panel[data-panel="v1"] { border-left: 3px solid var(--lapis); }
.page-about .tabs__panel[data-panel="v2"] { border-left: 3px solid var(--ochre); }
.page-about .tabs__panel[data-panel="v3"] { border-left: 3px solid var(--milan-red); }
.page-about .tabs__panel[data-panel="v4"] { border-left: 3px solid var(--turquoise); }
.page-about .tabs__panel[data-panel="v5"] { border-left: 3px solid var(--ember); }

.page-about .tabs__panel h3 {
  margin: 0 0 0.6rem;
  font-size: 1.125rem;
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--snow);
}

.page-about .tabs__panel p {
  margin: 0 0 0.9rem;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--fg-mute);
}

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

/* ---------- 编辑流程折线 ---------- */
.page-about .steps {
  margin: 1.75rem 0 0;
}

.page-about .steps__scroll {
  overflow-x: auto;
  padding: 0.5rem;
  border: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(31, 63, 160, 0.14), rgba(14, 13, 15, 0));
  scrollbar-width: thin;
}

.page-about .steps__scroll svg {
  display: block;
  width: 100%;
  min-width: 660px;
  height: auto;
  color: var(--ochre);
}

.page-about .steps__nodes circle {
  fill: var(--ochre);
}

.page-about .steps__labels text {
  fill: rgba(247, 244, 237, 0.68);
  font-family: var(--font-head);
  font-size: 13px;
  letter-spacing: 0.04em;
  text-anchor: middle;
}

.page-about .steps figcaption {
  margin-top: 0.65rem;
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  display: grid;
  gap: 1.1rem;
  padding: 1.5rem;
  border: 1px solid var(--line-strong);
  border-left: 6px solid var(--milan-red);
  background: var(--stand-paper);
  color: var(--deep-brown);
  box-shadow: 10px 12px 0 var(--about-shadow);
}

.page-about .about-cta__lead {
  margin: 0;
  max-width: 34rem;
  font-size: 1.0625rem;
  line-height: 1.7;
  font-weight: 700;
  color: var(--deep-brown);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

/* ---------- 桌面布局 ---------- */
@media (min-width: 700px) {
  .page-about .about-hero__key {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-hero__lede {
    font-size: 1.0625rem;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(220px, 0.72fr) minmax(0, 1.6fr);
    gap: 3rem;
    align-items: start;
    margin-top: 2.5rem;
  }

  .page-about .about-hero__shot {
    aspect-ratio: 3 / 4;
  }

  .page-about .about-shell {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: 2.75rem;
    align-items: start;
    margin-top: 4.5rem;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 2rem);
  }

  .page-about .about-rail__nav {
    flex-direction: column;
    gap: 0.15rem;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-rail__link {
    justify-content: flex-start;
    padding: 0.5rem 0.65rem;
  }

  .page-about .about-flow {
    gap: 4.5rem;
  }

  .page-about .era {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 2.5rem;
    padding-left: 2rem;
    align-items: start;
  }

  .page-about .era__year {
    order: 2;
    text-align: right;
    padding-top: 0.35rem;
  }

  .page-about .about-figure {
    max-width: 40rem;
  }

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: 2rem;
    padding: 2rem;
  }
}
</page_css>