.page-about {
  --about-rail: 132px;
  --about-radius: var(--radius-m);
  display: block;
  background: var(--paper);
  color: var(--ink);
}

.page-about a:focus-visible {
  outline: 2px solid var(--canal);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: clamp(18px, 3vw, 40px) 0 clamp(34px, 6vw, 76px);
  background:
    radial-gradient(118% 78% at 88% 0%, rgba(191, 211, 222, 0.6) 0%, rgba(191, 211, 222, 0) 60%),
    var(--paper);
}

.page-about .about-hero-inner {
  display: grid;
  gap: clamp(26px, 4vw, 48px);
}

.page-about .about-hero-media {
  position: relative;
}

.page-about .about-hero-media .img-frame {
  border-radius: var(--radius-l);
  overflow: hidden;
  background: var(--celadon-1);
}

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

.page-about .about-photo-note {
  position: absolute;
  left: 12px;
  bottom: 16px;
  z-index: 2;
  background: var(--paper);
  color: var(--celadon-3);
  font-size: 12px;
  letter-spacing: 0.12em;
  padding: 6px 13px;
  border-radius: 999px;
  box-shadow: 0 0 0 1px var(--celadon-2);
  transform: rotate(-6deg);
  white-space: nowrap;
}

.page-about .about-hero-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.page-about .about-hero-text .breadcrumb {
  margin: 0 0 clamp(18px, 2.6vw, 26px);
}

.page-about .about-hero-kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 14px;
  font-size: 13px;
  letter-spacing: 0.22em;
  color: var(--celadon-3);
}

.page-about .about-hero-kicker::before {
  content: "";
  width: 26px;
  height: 2px;
  border-radius: 999px;
  background: var(--orange);
}

.page-about .about-hero-text h1 {
  margin: 0 0 clamp(16px, 2.6vw, 26px);
  font-size: clamp(30px, 6vw, 50px);
  line-height: 1.26;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--ink-deep);
}

.page-about .about-lede {
  margin: 0;
  max-width: 30em;
  font-size: clamp(16px, 1.9vw, 19px);
  line-height: 1.95;
  color: var(--ink);
}

.page-about .about-facts {
  margin: clamp(26px, 4vw, 40px) 0 0;
  padding: 0;
  width: 100%;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  background: rgba(169, 187, 174, 0.55);
  border-radius: var(--about-radius);
  overflow: hidden;
}

.page-about .about-fact {
  padding: clamp(14px, 2.4vw, 20px);
  background: var(--paper);
}

.page-about .about-fact dt {
  margin-bottom: 8px;
  font-size: 12.5px;
  line-height: 1.6;
  letter-spacing: 0.06em;
  color: var(--celadon-3);
}

.page-about .about-fact dd {
  margin: 0;
  font-size: clamp(20px, 2.6vw, 26px);
  line-height: 1.2;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--ink-deep);
  font-variant-numeric: tabular-nums;
}

/* ---------- 长卷章节 ---------- */

.page-about .about-flow {
  padding-bottom: clamp(30px, 6vw, 90px);
}

.page-about .about-chapter {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  row-gap: clamp(16px, 3vw, 26px);
  padding-block: clamp(44px, 7vw, 96px);
}

.page-about .about-band {
  grid-column: 1 / -1;
  width: clamp(56px, 16vw, 128px);
  height: 4px;
  border-radius: 999px;
  background: var(--about-band, var(--celadon-2));
}

.page-about .about-chapter:nth-of-type(1) { --about-band: var(--celadon-2); }
.page-about .about-chapter:nth-of-type(2) { --about-band: var(--canal); }
.page-about .about-chapter:nth-of-type(3) { --about-band: var(--celadon-3); }
.page-about .about-chapter:nth-of-type(4) { --about-band: var(--orange); }
.page-about .about-chapter:nth-of-type(5) { --about-band: var(--celadon-2); }
.page-about .about-chapter:nth-of-type(6) { --about-band: var(--ink); }

.page-about .about-rail {
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.page-about .about-num-lg {
  font-size: clamp(30px, 4.6vw, 52px);
  line-height: 0.9;
  font-weight: 800;
  letter-spacing: -0.04em;
  color: var(--celadon-3);
  font-variant-numeric: tabular-nums;
}

.page-about .about-rail .annotation--vertical {
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--celadon-3);
}

.page-about .about-body h2 {
  margin: 0 0 clamp(14px, 2.4vw, 24px);
  max-width: 22em;
  font-size: clamp(24px, 3.6vw, 36px);
  line-height: 1.4;
  font-weight: 800;
  letter-spacing: -0.015em;
  color: var(--ink-deep);
}

.page-about .about-body h3 {
  margin: 0 0 8px;
  font-size: clamp(17px, 2.1vw, 20px);
  line-height: 1.5;
  font-weight: 700;
  color: var(--ink-deep);
}

.page-about .about-body p {
  margin: 0 0 1.1em;
  max-width: 34em;
  font-size: 17px;
  line-height: 1.95;
  color: var(--ink);
}

.page-about .about-body > p:last-child,
.page-about .about-body > *:last-child {
  margin-bottom: 0;
}

/* ---------- 图片 ---------- */

.page-about .about-fig {
  margin: clamp(20px, 3vw, 32px) 0;
}

.page-about .about-fig .img-frame {
  border-radius: var(--about-radius);
  overflow: hidden;
  background: var(--celadon-1);
}

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

.page-about .img-caption {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--celadon-3);
}

/* ---------- 四个方向 ---------- */

.page-about .about-topics {
  list-style: none;
  margin: clamp(22px, 3.5vw, 34px) 0 0;
  padding: 0;
  display: grid;
  gap: 3px;
  border-radius: var(--about-radius);
  overflow: hidden;
}

.page-about .about-topics > li {
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-height: 180px;
  padding: clamp(18px, 2.6vw, 26px);
  color: var(--ink);
}

.page-about .about-topics > li:nth-child(1) { background: var(--celadon-1); }
.page-about .about-topics > li:nth-child(2) { background: var(--celadon-2); }
.page-about .about-topics > li:nth-child(3) { background: var(--celadon-3); color: var(--paper); }
.page-about .about-topics > li:nth-child(4) { background: var(--ink); color: var(--paper); }

.page-about .about-topics .about-topic-name {
  margin: 0;
  font-size: 17px;
  letter-spacing: 0.02em;
  color: inherit;
}

.page-about .about-topics .about-topic-name::before {
  content: "";
  display: block;
  width: 16px;
  height: 16px;
  margin-bottom: 14px;
  border-radius: 50%;
  border: 2px solid currentColor;
  opacity: 0.5;
}

.page-about .about-topics > li p {
  margin: 0;
  max-width: none;
  font-size: 14px;
  line-height: 1.78;
  color: inherit;
  opacity: 0.88;
}

/* ---------- 版本时间轴 ---------- */

.page-about .about-wire {
  display: block;
  width: 100%;
  height: clamp(24px, 4vw, 38px);
  margin: clamp(6px, 1.4vw, 14px) 0 clamp(4px, 1vw, 10px);
  color: var(--canal-light);
}

.page-about .about-versions {
  list-style: none;
  margin: clamp(16px, 2.6vw, 26px) 0 0;
  padding: 0;
  display: grid;
  gap: clamp(12px, 2vw, 18px);
}

.page-about .about-version {
  padding: clamp(18px, 2.6vw, 28px) clamp(18px, 2.8vw, 30px);
  background: var(--paper-deep);
  border-radius: var(--about-radius);
  border-left: 5px solid var(--celadon-2);
  transition: border-color 180ms ease, background 180ms ease;
}

.page-about .about-version.is-lit {
  border-left-color: var(--canal);
}

.page-about .about-version:hover {
  border-left-color: var(--orange);
  background: var(--celadon-1);
}

.page-about .about-version-tag {
  display: inline-block;
  margin-bottom: 12px;
  padding: 3px 12px;
  font-size: 12.5px;
  letter-spacing: 0.16em;
  color: var(--canal);
  background: var(--canal-light);
  border-radius: 999px;
}

.page-about .about-version p {
  margin: 0;
  max-width: 32em;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-version-link {
  display: inline-block;
  margin-top: 14px;
  font-size: 14px;
  color: var(--canal);
  text-decoration: none;
  border-bottom: 1px solid var(--canal-light);
  transition: color 160ms ease, border-color 160ms ease;
}

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

/* ---------- 合作 ---------- */

.page-about .about-partners {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-partners > li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 16px;
  align-items: baseline;
  padding: clamp(16px, 2.4vw, 22px) clamp(18px, 2.6vw, 26px);
  background: var(--celadon-1);
  border-radius: var(--about-radius);
}

.page-about .about-partners-num {
  font-size: clamp(24px, 3.4vw, 34px);
  line-height: 1;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--celadon-3);
  font-variant-numeric: tabular-nums;
}

.page-about .about-partners-text {
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink);
}

/* ---------- 结尾入口 ---------- */

.page-about .about-next {
  display: grid;
  gap: 12px;
  margin-top: clamp(22px, 3.4vw, 34px);
}

.page-about .about-next-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-height: 172px;
  padding: clamp(20px, 2.8vw, 28px);
  background: var(--paper);
  border: 1px solid var(--celadon-2);
  border-radius: var(--about-radius);
  text-decoration: none;
  color: var(--ink);
  transition: border-color 160ms ease, background 160ms ease;
}

.page-about .about-next-card:hover {
  border-color: var(--orange);
  background: var(--orange-soft);
}

.page-about .about-next-kicker {
  font-size: 12.5px;
  letter-spacing: 0.16em;
  color: var(--celadon-3);
}

.page-about .about-next-title {
  font-size: 19px;
  line-height: 1.5;
  font-weight: 700;
  color: var(--ink-deep);
}

.page-about .about-next-desc {
  font-size: 14px;
  line-height: 1.78;
  color: var(--ink);
  opacity: 0.88;
}

.page-about .about-next-arrow {
  margin-top: auto;
  font-size: 20px;
  line-height: 1;
  color: var(--orange);
  transition: transform 160ms ease;
}

.page-about .about-next-card:hover .about-next-arrow {
  transform: translateX(4px);
}

/* ---------- 响应式 ---------- */

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

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

@media (min-width: 880px) {
  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 0.76fr) minmax(0, 1.24fr);
    align-items: end;
  }

  .page-about .about-photo-note {
    left: -10px;
  }

  .page-about .about-chapter {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    column-gap: clamp(28px, 5vw, 68px);
  }

  .page-about .about-rail {
    position: sticky;
    top: 104px;
    align-self: start;
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
    padding-top: 4px;
  }

  .page-about .about-rail .annotation--vertical {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    letter-spacing: 0.28em;
  }

  .page-about .about-topics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 1080px) {
  .page-about {
    --about-rail: 152px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-version,
  .page-about .about-version-link,
  .page-about .about-next-card,
  .page-about .about-next-arrow {
    transition: none;
  }

  .page-about .about-next-card:hover .about-next-arrow {
    transform: none;
  }
}