.page-about {
  background: var(--cream);
  color: var(--ink);
}

.page-about img {
  max-width: 100%;
  height: auto;
}

.page-about .about-crumb {
  padding-top: clamp(1.1rem, 3vw, 1.8rem);
}

/* ---------- 首屏框景 ---------- */

.page-about .about-hero-wrap {
  padding-bottom: clamp(1.4rem, 4vw, 2.6rem);
}

.page-about .about-hero {
  position: relative;
  display: grid;
  gap: clamp(0.9rem, 2.4vw, 1.5rem);
  background: var(--paper);
  border-radius: var(--r-lg);
  padding: clamp(1.5rem, 4.5vw, 3.4rem) clamp(1.1rem, 3.6vw, 3rem) clamp(1.6rem, 4.5vw, 3rem);
}

.page-about .about-hero__title {
  margin: 0;
  max-width: 22ch;
  color: var(--ink);
  font-size: clamp(1.85rem, 5.2vw, 3.5rem);
  font-weight: 300;
  line-height: 1.14;
  letter-spacing: -0.02em;
}

.page-about .about-hero__lead {
  margin: 0;
  max-width: 60ch;
  color: var(--taupe);
  font-size: clamp(1rem, 2.4vw, 1.125rem);
  line-height: 1.85;
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 0.4rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .about-hero__stats > li {
  background: var(--cream);
  padding: 0.9rem clamp(0.8rem, 2.4vw, 1.2rem);
}

.page-about .about-hero__stat-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.4rem, 3.6vw, 1.85rem);
  font-weight: 500;
  line-height: 1.1;
  color: var(--red-clay);
  letter-spacing: -0.02em;
}

.page-about .about-hero__stat-label {
  display: block;
  margin-top: 0.35rem;
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  color: var(--taupe);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
  margin-top: 0.3rem;
}

/* ---------- 起步段落（深湖绿带背景） ---------- */

.page-about .about-origin {
  position: relative;
  isolation: isolate;
  margin-top: clamp(2.2rem, 6vw, 4.2rem);
  padding-block: clamp(2.6rem, 8vw, 5.4rem);
  background: var(--lake);
  color: var(--gold-lite);
  overflow: hidden;
}

.page-about .about-origin__bg {
  position: absolute;
  inset: 0;
  z-index: -2;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.32;
}

.page-about .about-origin__veil {
  position: absolute;
  inset: 0;
  z-index: -1;
  background: rgba(14, 59, 54, 0.86);
}

.page-about .about-origin__title {
  margin: 0.6rem 0 1rem;
  color: var(--cream);
  font-weight: 300;
}

.page-about .about-origin__text {
  margin: 0 0 1rem;
  max-width: 62ch;
  color: var(--turq-lite);
  line-height: 1.85;
}

.page-about .about-origin__actions {
  margin: 1.4rem 0 0;
}

/* ---------- 主体两栏 ---------- */

.page-about .about-body {
  padding-block: clamp(2.4rem, 7vw, 4.6rem);
}

.page-about .about-body__grid > * {
  min-width: 0;
}

.page-about .about-block {
  padding-block: clamp(1.8rem, 5vw, 3rem);
  border-top: 1px solid var(--line);
}

.page-about .about-block:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-block__lead {
  margin: 0.9rem 0 0;
  color: var(--taupe);
  line-height: 1.85;
}

.page-about .about-block h2.h-2 {
  margin: 0.5rem 0 0;
  font-weight: 300;
}

/* 阶段刻度索引 */

.page-about .stage-index {
  margin-top: clamp(1.4rem, 4vw, 2rem);
  padding: clamp(1rem, 3vw, 1.4rem);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
}

.page-about .stage-index__list {
  list-style: none;
  margin: 0.8rem 0 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .stage-index__link {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  padding: 0.55rem 0.7rem;
  border-radius: var(--r-sm);
  text-decoration: none;
  color: var(--ink);
  transition: background 180ms var(--ease), color 180ms var(--ease);
}

.page-about .stage-index__link:hover,
.page-about .stage-index__link:focus-visible {
  background: var(--gold-lite);
  color: var(--red-deep);
}

.page-about .stage-index__num {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--red-clay);
  flex: none;
}

.page-about .stage-index__label {
  font-size: 0.95rem;
}

.page-about .stage-index__foot {
  margin: 1rem 0 0;
  padding-top: 0.9rem;
  border-top: 1px solid var(--line);
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--taupe);
  word-break: break-all;
}

/* 四类内容 */

.page-about .about-lanes {
  list-style: none;
  margin: 1.4rem 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .about-lane {
  background: var(--paper);
  padding: clamp(1rem, 3vw, 1.4rem);
  display: grid;
  gap: 0.45rem;
  align-content: start;
  transition: background 180ms var(--ease);
}

.page-about .about-lane:hover {
  background: var(--cream);
}

.page-about .about-lane__num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 500;
  line-height: 1;
  color: var(--gold);
}

.page-about .about-lane__title {
  margin: 0;
  font-weight: 500;
  color: var(--ink);
}

.page-about .about-lane__text {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--taupe);
}

.page-about .about-lane__link {
  justify-self: start;
  margin-top: 0.2rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--turq);
  text-decoration: none;
  border-bottom: 2px solid var(--turq-lite);
  padding-bottom: 2px;
  transition: color 180ms var(--ease), border-color 180ms var(--ease);
}

.page-about .about-lane__link:hover,
.page-about .about-lane__link:focus-visible {
  color: var(--red-clay);
  border-color: var(--gold);
}

.page-about .about-figure {
  margin: clamp(1.4rem, 4vw, 2.2rem) 0 0;
  border-radius: var(--r-md);
  overflow: hidden;
}

/* 团队 */

.page-about .about-ribbon {
  list-style: none;
  margin: 1.4rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.7rem;
}

.page-about .about-ribbon__item {
  padding: clamp(1rem, 3vw, 1.5rem);
  border-radius: var(--r-md);
  color: var(--cream);
}

.page-about .about-ribbon__item--red {
  background: var(--red-clay);
}

.page-about .about-ribbon__item--turq {
  background: var(--turq);
}

.page-about .about-ribbon__item--gold {
  background: var(--gold);
  color: var(--ink);
}

.page-about .about-ribbon__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.9rem;
  font-weight: 500;
  line-height: 1;
  opacity: 0.92;
}

.page-about .about-ribbon__role {
  margin: 0.5rem 0 0.35rem;
  font-weight: 500;
  font-size: 1.05rem;
}

.page-about .about-ribbon__text {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.75;
  opacity: 0.9;
}

.page-about .about-teamstack {
  margin-top: clamp(1.4rem, 4vw, 2.2rem);
  display: grid;
  gap: clamp(1rem, 3vw, 1.6rem);
}

.page-about .about-teamstack__fig {
  margin: 0;
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .about-teamstack__copy h3 {
  margin: 0 0 0.8rem;
  font-weight: 500;
}

.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.6rem;
  counter-reset: none;
}

.page-about .about-steps__item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.7rem;
  align-items: start;
  padding: 0.75rem 0.9rem;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
}

.page-about .about-steps__num {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--gold);
  background: var(--lake);
  border-radius: var(--r-pill);
  padding: 0.18rem 0.5rem;
  line-height: 1.6;
}

.page-about .about-steps__item p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.75;
  color: var(--taupe);
}

.page-about .about-teamstack__note {
  margin: 0.9rem 0 0;
  padding-left: 0.9rem;
  border-left: 3px solid var(--gold-lite);
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--taupe);
}

/* 覆盖范围 */

.page-about .about-audience {
  list-style: none;
  margin: 1.4rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.9rem;
}

.page-about .about-audience__item {
  padding: clamp(0.95rem, 3vw, 1.3rem);
  background: var(--paper);
  border: 1px solid var(--line);
  border-left: 4px solid var(--turq);
  border-radius: var(--r-sm);
}

.page-about .about-audience__item h3 {
  margin: 0 0 0.4rem;
  font-weight: 500;
}

.page-about .about-audience__item p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--taupe);
}

.page-about .about-coverage-wrap {
  margin-top: clamp(1.4rem, 4vw, 2rem);
  padding: clamp(1.1rem, 3.4vw, 1.6rem);
  background: var(--lake);
  border-radius: var(--r-md);
}

.page-about .about-coverage {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(16px, 1fr));
  gap: 6px;
  max-width: 430px;
  margin: 0;
}

.page-about .about-coverage__cell {
  aspect-ratio: 1 / 1;
  border-radius: 4px;
  background: var(--turq);
}

.page-about .about-coverage__cell--alt {
  background: var(--gold);
}

.page-about .about-coverage__cell--soft {
  background: var(--turq-lite);
}

.page-about .about-coverage__cap {
  margin: 1rem 0 0;
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--gold-lite);
}

/* 版本时间线 */

.page-about .about-timeline {
  list-style: none;
  margin: 1.4rem 0 0;
  padding: 0 0 0 clamp(0.9rem, 3vw, 1.4rem);
  border-left: 2px solid var(--red-clay);
  display: grid;
  gap: 0.75rem;
}

.page-about .about-stage {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-about .about-stage[open] {
  border-color: var(--gold);
}

.page-about .about-stage__head {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.9rem clamp(0.85rem, 2.8vw, 1.2rem);
  cursor: pointer;
  list-style: none;
}

.page-about .about-stage__head::-webkit-details-marker {
  display: none;
}

.page-about .about-stage__head::after {
  content: "展开";
  flex: none;
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--taupe);
}

.page-about .about-stage[open] .about-stage__head::after {
  content: "收起";
  color: var(--red-clay);
}

.page-about .about-stage__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--gold-lite);
  background: var(--lake);
  border-radius: var(--r-pill);
  padding: 0.2rem 0.6rem;
  line-height: 1.6;
}

.page-about .about-stage__name {
  flex: 1;
  font-weight: 500;
  color: var(--ink);
  font-size: 0.98rem;
}

.page-about .about-stage__body {
  padding: 0 clamp(0.85rem, 2.8vw, 1.2rem) 1.1rem;
  border-top: 1px solid var(--line);
}

.page-about .about-stage__body p {
  margin: 0.9rem 0 0;
  font-size: 0.94rem;
  line-height: 1.85;
  color: var(--taupe);
}

/* 归属与备案 */

.page-about .about-trust {
  margin-top: clamp(2.2rem, 6vw, 4.2rem);
  padding-block: clamp(2.4rem, 7vw, 4.2rem);
  background: var(--ink);
  color: var(--gold-lite);
}

.page-about .about-trust__title {
  margin: 0.6rem 0 1rem;
  color: var(--cream);
  font-weight: 300;
}

.page-about .about-trust__text {
  margin: 0 0 1.3rem;
  max-width: 62ch;
  color: var(--turq-lite);
  line-height: 1.85;
}

.page-about .about-trust__pills {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.page-about .about-trust__pill {
  border: 1px solid var(--line-soft);
  border-radius: var(--r-pill);
  padding: 0.5rem 1rem;
  font-size: 0.9rem;
  line-height: 1.5;
  color: var(--gold-lite);
  background: rgba(241, 226, 190, 0.06);
  word-break: break-all;
}

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

.page-about .about-trust__pill a:hover,
.page-about .about-trust__pill a:focus-visible {
  text-decoration: underline;
}

.page-about .about-trust__more {
  margin: 1.6rem 0 0;
}

/* ---------- 响应式增强 ---------- */

@media (min-width: 640px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about .stage-index {
    position: sticky;
    top: 5.5rem;
  }

  .page-about .about-teamstack {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-teamstack__fig {
    height: 100%;
  }

  .page-about .about-teamstack__fig .media__img {
    height: 100%;
    object-fit: cover;
  }

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

  .page-about .about-hero {
    padding-right: clamp(2rem, 6vw, 5rem);
  }
}

@media (min-width: 1120px) {
  .page-about .about-lanes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-coverage {
    max-width: 500px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .stage-index__link,
  .page-about .about-lane,
  .page-about .about-lane__link {
    transition: none;
  }
}