.page-about {
  --about-copy-width: 34em;
  background: var(--sand);
  color: var(--rock);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  overflow-x: hidden;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  margin: 0;
  font-family: var(--font-display);
  color: var(--rock-deep);
  line-height: 1.22;
  letter-spacing: -0.01em;
}

.page-about h1 { font-size: clamp(2rem, 6vw, 3.5rem); }
.page-about h2 { font-size: clamp(1.5rem, 4vw, 2.25rem); }
.page-about h3 { font-size: clamp(1.02rem, 2.2vw, 1.2rem); }

.page-about p { margin: 0 0 1em; }
.page-about p:last-child { margin-bottom: 0; }

.page-about .mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
}

.page-about .eyebrow {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cinnabar);
}

.page-about .annotation {
  margin: 14px 0 0;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  line-height: 1.65;
  color: var(--copper);
  border-left: 2px solid var(--copper-line);
  padding-left: 12px;
}

.page-about .section { padding: clamp(44px, 7vw, 90px) 0; }
.page-about .section--tight { padding: clamp(30px, 5vw, 56px) 0; }

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(22px, 4vw, 40px) 0 clamp(30px, 5vw, 56px);
  border-bottom: 3px solid var(--ink);
  background-color: var(--sand);
  background-image: repeating-linear-gradient(
    0deg,
    rgba(20, 19, 16, 0.035) 0 1px,
    rgba(20, 19, 16, 0) 1px 36px
  );
}

.page-about .about-hero .breadcrumb { margin-bottom: clamp(20px, 3.5vw, 36px); }

.page-about .about-hero__lead {
  max-width: 30em;
  margin-top: 16px;
  font-size: clamp(1rem, 2.1vw, 1.24rem);
  line-height: 1.75;
  color: var(--rock);
}

.page-about .hero-collage {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: clamp(24px, 4vw, 42px);
}

.page-about .hero-cell {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-height: 118px;
  padding: 14px 16px 16px;
  background: var(--cream);
  border: 2px solid var(--ink);
  border-radius: var(--radius);
  box-shadow: var(--shadow-hard-sm);
}

.page-about .hero-cell--lead {
  background: var(--rock-deep);
  border-color: var(--ink);
  box-shadow: 3px 3px 0 var(--copper);
}

.page-about .hero-cell__k {
  display: block;
  font-size: clamp(1.3rem, 3.6vw, 1.9rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--cinnabar);
}

.page-about .hero-cell--lead .hero-cell__k { color: var(--copper); }

.page-about .hero-cell__v {
  margin: 0;
  font-size: 0.84rem;
  line-height: 1.6;
  color: var(--rock);
}

.page-about .hero-cell--lead .hero-cell__v { color: rgba(251, 246, 234, 0.86); }

/* ---------- 双栏骨架 ---------- */
.page-about .about-duo {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 5vw, 48px);
  align-items: start;
}

.page-about .about-prose { max-width: var(--about-copy-width); }
.page-about .about-prose p { font-size: 1rem; line-height: 1.85; }

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

.page-about .about-frame {
  overflow: hidden;
  border: 2px solid var(--ink);
  border-radius: var(--radius);
  background: var(--sand-mid);
  box-shadow: var(--shadow-hard-sm);
  line-height: 0;
}

.page-about .about-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.94) contrast(1.04);
}

.page-about .about-caption {
  display: block;
  margin-top: 10px;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--copper);
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline__lead {
  max-width: 46em;
  font-size: clamp(1rem, 2vw, 1.12rem);
  line-height: 1.8;
  color: var(--rock);
}

.page-about .about-timeline__visual { margin-top: clamp(24px, 4vw, 40px); }

.page-about .tl-track {
  list-style: none;
  margin: clamp(28px, 5vw, 48px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 28px 22px;
  border-left: 2px solid var(--paper-line-strong);
}

.page-about .tl-item:last-child { padding-bottom: 0; }

.page-about .tl-mark {
  position: absolute;
  left: -7px;
  top: 6px;
  width: 12px;
  height: 12px;
  box-sizing: border-box;
  background: var(--copper);
  border: 2px solid var(--ink);
}

.page-about .tl-year {
  display: block;
  font-size: clamp(1.4rem, 4.4vw, 1.75rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--copper);
}

.page-about .tl-title { margin: 6px 0 8px; }

.page-about .tl-body {
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.75;
  color: var(--rock);
  max-width: 26em;
}

.page-about .tl-more {
  max-height: none;
  opacity: 1;
  overflow: visible;
  margin: 10px 0 0;
  padding-top: 10px;
  border-top: 1px dashed var(--copper-line);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  line-height: 1.7;
  color: var(--copper);
  max-width: 30em;
  transition: max-height 0.34s ease, opacity 0.24s ease,
              margin-top 0.34s ease, padding-top 0.34s ease;
}

.page-about .tl-item:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 4px;
}

/* ---------- 产能爬坡 ---------- */
.page-about .about-ramp__intro {
  max-width: 44em;
  margin-top: 14px;
  font-size: clamp(1rem, 2vw, 1.1rem);
  line-height: 1.8;
}

.page-about .ramp-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: clamp(26px, 4vw, 42px);
}

.page-about .ramp-card {
  position: relative;
  padding: 22px 20px 24px;
  background: var(--cream);
  border: 2px solid var(--ink);
  border-left: 10px solid var(--sand-mid);
  border-radius: var(--radius);
  transition: border-left-color 0.24s ease, transform 0.24s ease, box-shadow 0.24s ease;
}

.page-about .ramp-card:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 3px;
}

.page-about .ramp-card__idx {
  display: block;
  margin-bottom: 10px;
  font-size: 0.8rem;
  letter-spacing: 0.22em;
  color: var(--copper);
  transition: color 0.24s ease;
}

.page-about .ramp-card__title { margin-bottom: 10px; }

.page-about .ramp-card__body {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--rock);
}

/* ---------- 团队与质量 ---------- */
.page-about .about-duo--reverse { margin-bottom: clamp(26px, 4vw, 44px); }

.page-about .crew-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  padding: clamp(20px, 3.4vw, 32px);
  background: var(--sand-mid);
  border: 2px solid var(--ink);
  border-radius: var(--radius);
  box-shadow: var(--shadow-hard-sm);
}

.page-about .crew-panel__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px;
}

.page-about .crew-panel__num {
  font-size: clamp(2.2rem, 7vw, 3rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--rock-deep);
}

.page-about .crew-panel__unit {
  font-family: var(--font-display);
  font-size: 1.05rem;
  color: var(--rock);
}

.page-about .crew-panel__label {
  flex: 1 0 100%;
  margin: 0;
  font-size: 0.86rem;
  color: var(--rock);
}

.page-about .crew-panel__split { max-width: 34em; }

.page-about .crew-panel__split-label {
  margin: 0 0 8px;
  font-size: 0.76rem;
  letter-spacing: 0.1em;
  color: var(--rock);
}

.page-about .crew-panel__bar {
  height: 14px;
  background: var(--cream);
  border: 2px solid var(--ink);
  overflow: hidden;
}

.page-about .crew-panel__bar-fill {
  display: block;
  width: 70%;
  height: 100%;
  background: repeating-linear-gradient(
    135deg,
    var(--copper) 0 8px,
    var(--cinnabar) 8px 16px
  );
}

.page-about .crew-panel__split-note {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  line-height: 1.6;
  color: var(--rock);
}

/* ---------- 贺兰山分隔 ---------- */
.page-about .about-ridge {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 var(--gutter);
  color: var(--copper-line);
}

.page-about .about-ridge svg {
  display: block;
  width: 100%;
  height: clamp(30px, 5vw, 54px);
}

/* ---------- 宁夏根基 ---------- */
.page-about .about-base__intro {
  max-width: 44em;
  margin-top: 14px;
  font-size: clamp(1rem, 2vw, 1.1rem);
  line-height: 1.8;
}

.page-about .base-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin-top: clamp(24px, 4vw, 40px);
  border: 2px solid var(--ink);
  border-radius: var(--radius);
  background: var(--cream);
  box-shadow: var(--shadow-hard-sm);
}

.page-about .base-stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 20px 20px 22px;
  border-bottom: 1px solid var(--paper-line);
}

.page-about .base-stat:last-child { border-bottom: 0; }

.page-about .base-stat__num {
  font-size: clamp(1.5rem, 5vw, 2rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--cinnabar);
}

.page-about .base-stat__label {
  font-size: 0.86rem;
  line-height: 1.65;
  color: var(--rock);
}

.page-about .about-base__copy {
  margin-top: clamp(22px, 3.6vw, 34px);
}

/* ---------- 后续入口 ---------- */
.page-about .about-next {
  border-top: 3px solid var(--ink);
  background: var(--rock-deep);
  color: var(--cream);
}

.page-about .about-next h2 { color: var(--cream); }

.page-about .about-next__lead {
  max-width: 40em;
  margin-top: 12px;
  font-size: 0.96rem;
  line-height: 1.75;
  color: rgba(251, 246, 234, 0.78);
}

.page-about .about-next__list {
  list-style: none;
  margin: clamp(22px, 4vw, 36px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  border-top: 1px solid var(--cream-line);
}

.page-about .about-next__item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--cream-line);
}

.page-about .about-next__link {
  font-family: var(--font-display);
  font-size: clamp(1.15rem, 3vw, 1.45rem);
  color: var(--cream);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  align-self: flex-start;
  transition: color 0.2s ease, border-color 0.2s ease;
}

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

.page-about .about-next__link:focus-visible {
  outline: 2px solid var(--copper);
  outline-offset: 4px;
}

.page-about .about-next__desc {
  font-size: 0.84rem;
  line-height: 1.65;
  color: rgba(251, 246, 234, 0.7);
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .ramp-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .base-panel {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .base-stat {
    border-bottom: 0;
    border-right: 1px solid var(--paper-line);
  }

  .page-about .base-stat:last-child { border-right: 0; }
}

@media (min-width: 820px) {
  .page-about .hero-collage {
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 14px;
  }

  .page-about .hero-cell { min-height: 150px; }

  .page-about .about-next__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0 28px;
  }

  .page-about .about-next__item {
    border-bottom: 0;
    padding: 22px 0 4px;
  }
}

@media (min-width: 900px) {
  .page-about .about-duo {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: clamp(34px, 5vw, 64px);
  }

  .page-about .about-duo--reverse {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
  }

  .page-about .about-duo--reverse .about-chapter__side { order: -1; }

  .page-about .tl-track {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
    border-top: 3px solid var(--ink);
  }

  .page-about .tl-item {
    position: relative;
    padding: 30px 24px 10px 0;
    border-left: 0;
    border-right: 1px solid var(--paper-line);
  }

  .page-about .tl-item:not(:first-child) { padding-left: 24px; }
  .page-about .tl-item:last-child { border-right: 0; padding-right: 0; }

  .page-about .tl-mark {
    left: 0;
    top: -9px;
    width: 14px;
    height: 14px;
  }

  .page-about .tl-item:not(:first-child) .tl-mark { left: 24px; }

  .page-about .tl-more {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    margin-top: 0;
    padding-top: 0;
    border-top-color: transparent;
  }

  .page-about .tl-item:hover .tl-more,
  .page-about .tl-item:focus .tl-more,
  .page-about .tl-item:focus-within .tl-more {
    max-height: 260px;
    opacity: 1;
    margin-top: 10px;
    padding-top: 10px;
    border-top-color: var(--copper-line);
  }

  .page-about .tl-item:hover .tl-year,
  .page-about .tl-item:focus .tl-year,
  .page-about .tl-item:focus-within .tl-year {
    color: var(--cinnabar);
  }

  .page-about .ramp-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .ramp-card:hover,
  .page-about .ramp-card:focus-visible {
    border-left-color: var(--cinnabar);
    transform: translate(-2px, -2px);
    box-shadow: var(--shadow-hard-sm);
  }

  .page-about .ramp-card:hover .ramp-card__idx,
  .page-about .ramp-card:focus-visible .ramp-card__idx {
    color: var(--cinnabar);
  }

  .page-about .crew-panel {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.4fr);
    align-items: center;
    gap: 32px;
  }

  .page-about .crew-panel__split { max-width: none; }
}

@media (min-width: 1100px) {
  .page-about .about-hero { padding-bottom: clamp(44px, 5vw, 64px); }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-more,
  .page-about .ramp-card,
  .page-about .ramp-card__idx,
  .page-about .about-next__link,
  .page-about .tl-year {
    transition: none;
  }

  .page-about .ramp-card:hover,
  .page-about .ramp-card:focus-visible { transform: none; }
}