.page-about {
  --about-node: 18px;
  --about-indent: 32px;
  background: var(--cream);
  color: var(--brown);
  overflow-x: clip;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  margin: 20px 0 0;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  background: var(--ink-green);
  color: var(--cream);
  padding: 32px 0 56px;
  margin-top: 12px;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: min(52%, 560px);
  height: 100%;
  background: var(--slate);
  clip-path: polygon(40% 0, 100% 0, 100% 100%, 0 100%);
  z-index: 0;
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 32px;
  align-items: end;
}

.page-about .about-hero .index-label {
  color: var(--turf);
  margin: 0;
}

.page-about .about-hero__title {
  margin: 12px 0 0;
  font-family: var(--sans);
  font-weight: 900;
  font-size: clamp(2.9rem, 13vw, 6.6rem);
  line-height: 0.92;
  letter-spacing: -0.02em;
  color: var(--cream);
}

.page-about .about-hero__lede {
  margin: 18px 0 0;
  max-width: 58ch;
  font-size: 1rem;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .about-hero__plate {
  position: relative;
  background: var(--fog);
  color: var(--brown);
  border: 2px solid var(--ink-green);
  box-shadow: 6px 6px 0 var(--amber);
  padding: 20px;
  transform: rotate(-1.2deg);
}

.page-about .about-hero__plate .unit-label {
  margin: 0;
  color: var(--slate);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 14px 0 0;
  padding: 14px 0 0;
  border-top: var(--hair) solid var(--line-blue);
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.page-about .about-stat__v {
  display: block;
  font-family: var(--mono);
  font-weight: 600;
  font-size: clamp(1.5rem, 5vw, 2.3rem);
  line-height: 1;
  color: var(--ink-green);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stat__k {
  display: block;
  margin-top: 8px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--slate);
}

.page-about .about-hero__note {
  margin: 16px 0 0;
  padding-top: 12px;
  border-top: var(--hair) solid var(--line-blue);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--amber-ink);
}

/* ---------- 图片容器 ---------- */
.page-about .image-frame {
  border: 2px solid var(--ink-green);
  box-shadow: var(--shadow-hard);
  background: var(--mist);
}

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

.page-about .image-frame__cap {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
}

.page-about .about-banner {
  margin-top: 32px;
}

/* ---------- 分区节奏 ---------- */
.page-about .section {
  padding-block: 52px;
}

.page-about .section__head {
  margin-bottom: 28px;
}

/* ---------- 起点 ---------- */
.page-about .about-origin__grid {
  display: grid;
  gap: var(--gutter);
}

.page-about .about-origin__prose p {
  margin-top: 0;
}

.page-about .about-rules {
  align-self: start;
}

.page-about .about-rules__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-rules__list li {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  font-size: 0.95rem;
  line-height: 1.7;
}

.page-about .about-rules__list .num {
  font-family: var(--mono);
  font-weight: 600;
  color: var(--amber-ink);
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 4px 0 4px var(--about-indent);
  border-left: 2px solid var(--ink-green);
}

.page-about .about-timeline .timeline__item {
  position: relative;
  padding: 0 0 44px;
}

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

.page-about .about-timeline .timeline__item::before {
  content: "";
  position: absolute;
  top: 4px;
  left: calc(-1 * var(--about-indent) - 1px - var(--about-node) / 2);
  width: var(--about-node);
  height: var(--about-node);
  background: var(--amber);
  border: 2px solid var(--ink-green);
  box-sizing: border-box;
}

.page-about .timeline__round {
  display: inline-block;
  padding: 3px 9px;
  background: var(--mist);
  border: 1px solid var(--line-blue);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--slate);
}

.page-about .about-stage__title {
  margin: 12px 0 6px;
  font-family: var(--sans);
  font-weight: 600;
  font-size: clamp(1.25rem, 4.4vw, 1.7rem);
  line-height: 1.25;
  color: var(--brown);
}

.page-about .timeline__meta {
  margin: 0 0 12px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--turf-ink);
}

.page-about .about-stage__text {
  margin: 0;
  max-width: 62ch;
  font-size: 0.975rem;
  line-height: 1.78;
}

.page-about .about-stage__facts {
  margin: 16px 0 0;
  display: grid;
  gap: 12px;
}

.page-about .about-stage__facts > div {
  border-top: var(--hair) solid var(--line-blue);
  padding-top: 10px;
}

.page-about .about-stage__facts dt {
  margin-bottom: 6px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--slate);
}

.page-about .about-stage__facts dd {
  margin: 0;
  font-size: 0.925rem;
  line-height: 1.65;
}

/* ---------- 阶段对照表 ---------- */
.page-about .about-table-wrap {
  margin-top: 44px;
  overflow-x: auto;
  border: 2px solid var(--ink-green);
  box-shadow: var(--shadow-hard);
  background: var(--fog);
  -webkit-overflow-scrolling: touch;
}

.page-about .about-table {
  width: 100%;
  min-width: 780px;
  border-collapse: collapse;
}

.page-about .about-table caption {
  caption-side: top;
  text-align: left;
  padding: 14px 16px 12px;
  color: var(--slate);
}

.page-about .about-table th,
.page-about .about-table td {
  font-variant-numeric: tabular-nums;
}

.page-about .about-table tbody th {
  font-weight: 600;
  text-align: left;
}

/* ---------- 叙事框架 ---------- */
.page-about .about-frame {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 2px solid var(--ink-green);
}

.page-about .about-frame__item {
  padding: 22px 0;
  border-bottom: var(--hair) solid var(--line-blue);
}

.page-about .about-frame__no {
  display: block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--amber-ink);
}

.page-about .about-frame__name {
  margin: 8px 0 8px;
  font-family: var(--sans);
  font-weight: 600;
  font-size: 1.15rem;
  line-height: 1.3;
  color: var(--ink-green);
}

.page-about .about-frame__item p {
  margin: 0;
  max-width: 40ch;
  font-size: 0.94rem;
  line-height: 1.7;
}

.page-about .about-frame__foot {
  margin: 28px 0 0;
  max-width: 68ch;
  padding-left: 16px;
  border-left: 4px solid var(--turf);
  font-size: 0.975rem;
  line-height: 1.78;
  color: var(--slate);
}

/* ---------- 分工 ---------- */
.page-about .about-roles__grid {
  display: grid;
  gap: var(--gutter);
}

.page-about .about-roles__text .prose h3 {
  margin: 26px 0 8px;
  font-family: var(--sans);
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--ink-green);
}

.page-about .about-roles__text .prose h3:first-of-type {
  margin-top: 18px;
}

.page-about .about-roles__figure {
  align-self: start;
}

/* ---------- 可展开组 ---------- */
.page-about .about-accordion {
  border-top: 2px solid var(--ink-green);
}

.page-about .about-accordion__h {
  margin: 0;
  font-size: 1rem;
  font-weight: 400;
}

.page-about .accordion__item {
  border-bottom: var(--hair) solid var(--line-blue);
  background: transparent;
}

.page-about .accordion__trigger {
  width: 100%;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 14px;
  padding: 18px 0;
  background: transparent;
  border: 0;
  text-align: left;
  cursor: pointer;
  font-family: var(--sans);
  font-weight: 600;
  font-size: 1rem;
  line-height: 1.5;
  color: var(--brown);
  transition: color 240ms var(--ease);
}

.page-about .accordion__trigger:hover {
  color: var(--ink-green);
}

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

.page-about .accordion__index {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--slate);
}

.page-about .accordion__sign {
  font-family: var(--mono);
  font-size: 1.1rem;
  line-height: 1;
  color: var(--amber-ink);
  transition: transform 240ms var(--ease);
}

.page-about .accordion__item[data-open] .accordion__sign {
  transform: rotate(45deg);
}

.page-about .accordion__item[data-open] .accordion__index {
  color: var(--turf-ink);
}

.page-about .accordion__panel {
  padding: 0 0 20px;
}

.page-about .accordion__panel p {
  margin: 0;
  max-width: 66ch;
  font-size: 0.95rem;
  line-height: 1.78;
  color: var(--slate);
}

/* ---------- 下一步 ---------- */
.page-about .about-next__grid {
  display: grid;
  gap: var(--gutter);
}

.page-about .about-next__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 28px 0 0;
}

.page-about .about-next__figure {
  align-self: start;
}

/* ---------- 继续阅读 ---------- */
.page-about .about-links {
  margin-top: 24px;
  padding: 36px 0 48px;
  background: var(--mist);
  border-top: 2px solid var(--ink-green);
  border-bottom: 2px solid var(--ink-green);
}

.page-about .about-links .index-label {
  margin: 0;
  color: var(--slate);
}

.page-about .about-links__list {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-links__list a {
  display: inline-block;
  padding: 10px 16px;
  border: 2px solid var(--ink-green);
  background: var(--fog);
  color: var(--brown);
  font-size: 0.9rem;
  text-decoration: none;
  box-shadow: var(--shadow-hard-sm);
  transition: background-color 240ms var(--ease), color 240ms var(--ease);
}

.page-about .about-links__list a:hover,
.page-about .about-links__list a:focus-visible {
  background: var(--ink-green);
  color: var(--cream);
}

.page-about .about-links__list a:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 2px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .page-about .about-stage__facts {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-hero {
    padding: 44px 0 72px;
  }
}

@media (min-width: 860px) {
  .page-about .about-frame {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-frame__item {
    border-bottom: 0;
    border-left: var(--hair) solid var(--line-blue);
    padding: 22px 20px 4px 20px;
  }

  .page-about .about-frame__item:first-child {
    border-left: 0;
    padding-left: 0;
  }
}

@media (min-width: 900px) {
  .page-about {
    --about-node: 22px;
    --about-indent: 40px;
  }

  .page-about .section {
    padding-block: 80px;
  }

  .page-about .about-hero {
    padding: 56px 0 88px;
  }

  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 56px;
  }

  .page-about .about-origin__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-roles__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 40px;
  }

  .page-about .about-next__grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 6fr);
    gap: 40px;
  }

  .page-about .about-timeline .timeline__item {
    padding-bottom: 64px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-hero__plate {
    transform: none;
  }

  .page-about .accordion__sign,
  .page-about .accordion__trigger,
  .page-about .about-links__list a {
    transition: none;
  }
}