.page-about {
  background: var(--ink);
  color: var(--bone);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about .breadcrumb {
  padding: 26px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--slate);
}

.page-about .breadcrumb a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 180ms ease, border-color 180ms ease;
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
  outline: none;
}

.page-about .breadcrumb__sep {
  margin: 0 8px;
  color: var(--slate);
}

/* ---------- 首屏 ---------- */
.page-about .mission-hero {
  padding: 40px 0 72px;
}

.page-about .mission-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
}

.page-about .mission-hero .eyebrow {
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.26em;
  color: var(--cyan);
  text-transform: uppercase;
}

.page-about .mission-hero h1 {
  margin: 14px 0 24px;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(36px, 7.4vw, 76px);
  line-height: 1.04;
  letter-spacing: -0.012em;
  color: var(--bone);
}

.page-about .mission-hero .lede {
  max-width: 38em;
  margin: 0;
  font-size: 17px;
  line-height: 1.9;
  color: var(--mist);
}

.page-about .mission-hero__facts {
  display: grid;
  gap: 22px;
  padding-left: 20px;
  border-left: 2px solid var(--wine);
}

.page-about .mission-hero__facts .stat__value {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(32px, 4vw, 42px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--orange);
}

.page-about .mission-hero__facts .stat__label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--slate);
}

/* ---------- 章节骨架 ---------- */
.page-about .mission-chapter {
  position: relative;
  padding: 64px 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .mission-chapter--deep {
  background: var(--deep);
}

.page-about .mission-chapter__body {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .mission-note {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--slate);
  transition: color 220ms ease;
}

.page-about .mission-chapter__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 22px;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--line);
}

.page-about .mission-chapter__num {
  flex: none;
  padding: 4px 9px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--cyan);
  border: 1px solid rgba(43, 232, 200, 0.42);
}

.page-about .mission-chapter__title {
  flex: 1 1 300px;
  margin: 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(23px, 3.5vw, 38px);
  line-height: 1.22;
  letter-spacing: -0.005em;
  color: var(--bone);
}

.page-about .mission-copy p {
  max-width: 38em;
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.92;
  color: var(--mist);
}

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

/* ---------- 图片 ---------- */
.page-about .mission-figure {
  margin: 0;
  background: var(--carbon);
  border: 1px solid var(--line);
  overflow: hidden;
}

.page-about .mission-figure__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.9) contrast(1.1) brightness(0.84);
}

.page-about .mission-figure--wide {
  margin-bottom: 34px;
}

.page-about .mission-figure--wide .mission-figure__img {
  aspect-ratio: 16 / 7;
}

.page-about .mission-figure--tall .mission-figure__img {
  aspect-ratio: 3 / 4;
}

/* ---------- 图文分栏 ---------- */
.page-about .mission-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
}

/* ---------- 版本坐标轴 ---------- */
.page-about .mission-axis-wrap {
  margin: 30px 0 36px;
  padding: 18px 10px;
  border: 1px solid var(--line);
  background: rgba(36, 27, 63, 0.42);
}

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

.page-about .axis-node circle {
  transition: fill 200ms ease, stroke 200ms ease, stroke-width 200ms ease;
}

.page-about .axis-node__ver {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  fill: var(--bone);
  transition: fill 200ms ease;
}

.page-about .axis-node__ver--now {
  fill: var(--orange);
}

.page-about .axis-node__desc {
  font-family: var(--font-body);
  font-size: 13px;
  fill: var(--slate);
}

.page-about .axis-node:hover circle {
  fill: var(--cyan);
  stroke: var(--cyan);
  stroke-width: 3;
}

.page-about .axis-node:hover .axis-node__ver {
  fill: var(--cyan);
}

/* ---------- 收束 ---------- */
.page-about .mission-outro {
  padding: 68px 0 76px;
  background: var(--wine);
  border-top: 1px solid var(--line-light);
}

.page-about .mission-outro__tick {
  margin: 0 0 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.24em;
  color: rgba(243, 240, 231, 0.55);
}

.page-about .mission-outro__title {
  margin: 0 0 20px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(24px, 4vw, 40px);
  line-height: 1.2;
  color: var(--bone);
}

.page-about .mission-outro__text {
  max-width: 42em;
  margin: 0 0 32px;
  font-size: 16px;
  line-height: 1.9;
  color: rgba(243, 240, 231, 0.86);
}

.page-about .mission-outro__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .mission-outro__links a {
  display: inline-block;
  padding: 10px 18px;
  font-size: 14px;
  letter-spacing: 0.04em;
  color: var(--bone);
  text-decoration: none;
  border: 1px solid rgba(243, 240, 231, 0.42);
  transition: background 180ms ease, border-color 180ms ease, color 180ms ease;
}

.page-about .mission-outro__links a:hover,
.page-about .mission-outro__links a:focus-visible {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink);
  outline: none;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .mission-hero {
    padding: 52px 0 84px;
  }

  .page-about .mission-hero__facts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 28px;
    padding: 22px 0 0;
    border-left: 0;
    border-top: 2px solid var(--wine);
  }
}

@media (min-width: 900px) {
  .page-about .mission-split {
    grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
    gap: 48px;
    align-items: start;
  }

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

@media (min-width: 960px) {
  .page-about .mission-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: 64px;
    align-items: end;
  }

  .page-about .mission-hero__facts {
    display: grid;
    grid-template-columns: 1fr;
    gap: 26px;
    padding: 0 0 0 22px;
    border-top: 0;
    border-left: 2px solid var(--wine);
  }
}

@media (min-width: 1024px) {
  .page-about .mission-chapter {
    padding: 84px 0;
  }

  .page-about .mission-chapter__body {
    grid-template-columns: 46px minmax(0, 1fr);
    gap: 40px;
  }

  .page-about .mission-note {
    padding: 4px 0 0 12px;
    border-left: 1px solid var(--line);
    writing-mode: vertical-rl;
    letter-spacing: 0.34em;
    justify-self: start;
  }

  .page-about .mission-chapter:hover .mission-note,
  .page-about .mission-chapter:focus-within .mission-note {
    color: var(--cyan);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .mission-note,
  .page-about .axis-node circle,
  .page-about .axis-node__ver,
  .page-about .mission-outro__links a,
  .page-about .breadcrumb a {
    transition: none;
  }
}