.page-about {
  --about-gap: clamp(3rem, 7vw, 6rem);
  --about-idx-w: 208px;
  background: var(--abyss);
  color: var(--paper);
  padding-bottom: clamp(3rem, 7vw, 6rem);
}

.page-about .crumbs {
  padding-top: 1.25rem;
  font-size: 0.8125rem;
  color: var(--mist);
}

.page-about .crumbs a {
  color: var(--mist);
  text-decoration: none;
}

.page-about .crumbs a:hover {
  color: var(--cyan);
}

/* ---------- 首屏刊头 ---------- */
.page-about .about-hero {
  position: relative;
  text-align: center;
  padding-block: clamp(2rem, 5vw, 3.5rem) clamp(1.75rem, 4vw, 2.5rem);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -8% -18% auto;
  height: 420px;
  background: radial-gradient(52% 62% at 50% 0%, rgba(34, 211, 238, 0.13), transparent 72%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-hero > * {
  position: relative;
  z-index: 1;
}

.page-about .about-hero h1 {
  margin: 0.85rem auto 0;
  max-width: 20ch;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2rem, 6.4vw, 4.2rem);
  line-height: 1.1;
  letter-spacing: -0.015em;
}

.page-about .about-hero__lede {
  max-width: 62ch;
  margin: 1.15rem auto 0;
  color: var(--mist);
  font-size: clamp(1rem, 2vw, 1.0625rem);
  line-height: 1.9;
}

/* ---------- 四段流程条 ---------- */
.page-about .flow-list {
  list-style: none;
  margin: clamp(2rem, 4vw, 2.75rem) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  grid-template-columns: minmax(0, 1fr);
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  text-align: left;
}

.page-about .flow-node {
  position: relative;
  display: grid;
  gap: 0.3rem;
  padding: 1rem 1.1rem 1.2rem;
  background: var(--night);
  transition: background 0.25s var(--ease);
}

.page-about .flow-node::after {
  content: "";
  position: absolute;
  left: 1.1rem;
  right: 1.1rem;
  top: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--cyan), transparent);
  opacity: 0.5;
}

.page-about .flow-node:hover {
  background: var(--hull);
}

.page-about .flow-node__idx {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .flow-node__name {
  font-size: 0.9375rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.page-about .flow-node__desc {
  font-size: 0.8125rem;
  line-height: 1.65;
  color: var(--mist);
}

/* ---------- 首屏主图 ---------- */
.page-about .about-hero__media {
  margin-top: clamp(1.75rem, 4vw, 2.5rem);
  margin-bottom: 0;
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.page-about .about-hero__media figcaption,
.page-about .about-figure figcaption {
  margin-top: 0.75rem;
  font-size: 0.8125rem;
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 双栏叙事外壳 ---------- */
.page-about .about-shell {
  margin-top: var(--about-gap);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
}

/* ---------- 左侧章节索引 ---------- */
.page-about .about-index {
  border-top: 1px solid var(--line);
  padding-top: 0.9rem;
  margin-bottom: 1.75rem;
}

.page-about .about-index__label {
  margin: 0 0 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.page-about .about-index__list a {
  display: block;
  padding: 0.3rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 0.75rem;
  color: var(--mist);
  text-decoration: none;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  color: var(--abyss);
  background: var(--cyan);
  border-color: var(--cyan);
}

/* ---------- 章节 ---------- */
.page-about .about-chapter {
  border-top: 1px solid var(--line-soft);
  padding-block: clamp(2.25rem, 5vw, 3.25rem);
}

.page-about .about-body > .about-chapter:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-chapter__title {
  margin: 0.65rem 0 1rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.5rem, 4.2vw, 2.25rem);
  line-height: 1.22;
  letter-spacing: -0.01em;
}

.page-about .about-chapter__lede {
  margin: 0 0 1.5rem;
  max-width: 62ch;
  color: var(--mist);
  font-size: 1rem;
  line-height: 1.9;
}

.page-about .about-chapter .prose p {
  margin: 0 0 1.05rem;
  max-width: 66ch;
  font-size: clamp(1rem, 1.9vw, 1.0625rem);
  line-height: 1.9;
  color: var(--mist);
}

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

/* ---------- 数字呼吸区 ---------- */
.page-about .stat-band {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-block: clamp(1.5rem, 4vw, 2.5rem);
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .stat-cell {
  background: var(--abyss);
  padding: 1.35rem 1.1rem 1.5rem;
}

.page-about .stat-num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(1.75rem, 4.6vw, 2.5rem);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--amber);
}

.page-about .stat-label {
  margin: 0.55rem 0 0;
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  color: var(--mist);
}

/* ---------- 版本演进时间轴 ---------- */
.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 1.75rem;
  position: relative;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 0.375rem;
  top: 0.55rem;
  bottom: 0.75rem;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), var(--amber) 62%, var(--coral));
  opacity: 0.55;
}

.page-about .timeline__item {
  position: relative;
  padding-bottom: 1.85rem;
}

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

.page-about .timeline__item::before {
  content: "";
  position: absolute;
  left: -1.75rem;
  top: 0.32rem;
  width: 0.75rem;
  height: 0.75rem;
  border-radius: 50%;
  border: 1px solid var(--cyan);
  background: var(--abyss);
  box-shadow: 0 0 0 4px rgba(34, 211, 238, 0.1);
}

.page-about .timeline__item:last-child::before {
  border-color: var(--amber);
  box-shadow: 0 0 0 4px rgba(245, 183, 66, 0.12);
}

.page-about .timeline__stage {
  margin: 0 0 0.3rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  color: var(--amber);
}

.page-about .timeline__title {
  margin: 0 0 0.45rem;
  font-size: 1.0625rem;
  font-weight: 700;
  line-height: 1.45;
}

.page-about .timeline__text {
  margin: 0;
  max-width: 62ch;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 插图 ---------- */
.page-about .about-figure {
  margin: clamp(1.75rem, 4vw, 2.5rem) 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

/* ---------- 团队工位 ---------- */
.page-about .team-grid {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .team-cell {
  background: var(--hull);
  padding: 1.25rem 1.2rem 1.4rem;
}

.page-about .team-cell__idx {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .team-cell__name {
  margin: 0.45rem 0 0.5rem;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.page-about .team-cell__text {
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 使用场景 ---------- */
.page-about .scene-list {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.9rem;
}

.page-about .scene-list li {
  display: grid;
  grid-template-columns: 2.1rem minmax(0, 1fr);
  gap: 0.9rem;
  padding: 1rem 1.1rem;
  background: var(--night);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .scene-list strong {
  color: var(--paper);
  font-weight: 700;
}

.page-about .scene-list__num {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--amber);
  padding-top: 0.25rem;
}

/* ---------- 结尾理由 ---------- */
.page-about .about-chapter--closing {
  border-top-color: var(--line);
}

.page-about .reason-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: 1.5rem;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .reason-card {
  background: var(--abyss);
  padding: 1.35rem 1.2rem 1.5rem;
}

.page-about .reason-card h3 {
  margin: 0 0 0.6rem;
  font-size: 1.0625rem;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .reason-card p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.85;
  color: var(--mist);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .stat-band {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .page-about .flow-list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

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

@media (min-width: 960px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-idx-w) minmax(0, 1fr);
    gap: clamp(2rem, 4vw, 3.5rem);
  }

  .page-about .about-index {
    position: sticky;
    top: 6.5rem;
    align-self: start;
    margin-bottom: 0;
  }

  .page-about .about-index__list {
    display: block;
  }

  .page-about .about-index__list a {
    padding: 0.35rem 0;
    border: 0;
    border-bottom: 1px solid transparent;
    border-radius: 0;
    font-size: 0.8425rem;
  }

  .page-about .about-index__list a:hover,
  .page-about .about-index__list a:focus-visible {
    background: transparent;
    color: var(--cyan);
    border-bottom-color: var(--cyan);
  }

  .page-about .about-hero h1 {
    max-width: 22ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .flow-node,
  .page-about .about-index__list a {
    transition: none;
  }
}