.page-about {
  --about-rail: 172px;
  --about-gutter: clamp(1.25rem, 5vw, 4.5rem);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(1.75rem, 5vw, 3rem) clamp(2.25rem, 6vw, 4rem);
  background:
    radial-gradient(120% 96% at 86% -14%, rgba(59, 247, 203, 0.11), transparent 58%),
    linear-gradient(180deg, var(--c-black), var(--c-night));
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(
    90deg,
    rgba(20, 72, 58, 0.5) 0 1px,
    transparent 1px 118px
  );
  opacity: 0.65;
}

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

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(1.5rem, 4vw, 2.75rem);
}

.page-about .about-hero__eyebrow {
  margin: 0 0 0.85rem;
  font-family: var(--mono);
  font-size: 0.76rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.page-about .about-hero h1 {
  margin: 0 0 1.35rem;
  max-width: 15ch;
  font-size: clamp(2.05rem, 7.4vw, 4.3rem);
  font-weight: 900;
  line-height: 1.04;
  letter-spacing: -0.038em;
  color: var(--c-white);
}

.page-about .about-hero__lede {
  max-width: 58ch;
  margin: 0;
  font-size: clamp(1rem, 2.4vw, 1.08rem);
  line-height: 1.78;
  color: var(--c-muted);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(2rem, 5vw, 3rem) 0 0;
  border: 1px solid var(--c-line);
  background: var(--c-line);
}

.page-about .about-hero__fact {
  background: var(--c-night);
  padding: 1.05rem 1.1rem 1.15rem;
}

.page-about .about-hero__fact dt {
  font-family: var(--mono);
  font-size: clamp(1.25rem, 3.6vw, 1.85rem);
  line-height: 1.1;
  color: var(--c-cyan);
}

.page-about .about-hero__fact dd {
  margin: 0.4rem 0 0;
  font-size: 0.84rem;
  line-height: 1.55;
  color: var(--c-muted);
}

.page-about .about-jump {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: clamp(1.5rem, 4vw, 2.25rem);
}

.page-about .about-jump a {
  padding: 0.45rem 0.72rem;
  border: 1px solid var(--c-line);
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--c-muted);
  text-decoration: none;
  transition: color 120ms var(--ease), border-color 120ms var(--ease);
}

.page-about .about-jump a:hover,
.page-about .about-jump a:focus-visible {
  color: var(--c-cyan);
  border-color: var(--c-cyan);
}

.page-about .about-jump a:focus-visible {
  outline: 1px solid var(--c-cyan);
  outline-offset: 2px;
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  padding-block: clamp(3rem, 9vw, 6.5rem);
  border-top: 1px solid var(--c-line);
}

.page-about .about-chapter__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.25rem;
}

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

.page-about .about-chapter__rail .section__num {
  display: block;
  font-family: var(--mono);
  font-size: clamp(2.6rem, 11vw, 6.5rem);
  font-weight: 900;
  line-height: 0.82;
  letter-spacing: -0.05em;
  color: var(--c-line);
  margin-bottom: 0.35rem;
}

@supports (-webkit-text-stroke: 1px #000) {
  .page-about .about-chapter__rail .section__num {
    color: transparent;
    -webkit-text-stroke: 1px var(--c-line);
  }
}

.page-about .about-chapter__body {
  min-width: 0;
}

.page-about .about-chapter__body > p {
  max-width: 62ch;
  margin: 0 0 1.15rem;
  font-size: 1rem;
  line-height: 1.75;
  color: var(--c-muted);
}

.page-about .about-chapter__body > p a {
  color: var(--c-cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-chapter .section__title {
  max-width: 21ch;
  margin: 0 0 1.35rem;
  font-size: clamp(1.7rem, 4.8vw, 2.9rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.03em;
  color: var(--c-white);
}

.page-about .about-chapter__body h3 {
  margin: 0 0 0.55rem;
  font-size: 1.06rem;
  font-weight: 800;
  line-height: 1.35;
  letter-spacing: -0.012em;
  color: var(--c-white);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: clamp(1.75rem, 4.5vw, 2.75rem) 0;
}

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

.page-about .media__caption {
  margin-top: 0.7rem;
  font-size: 0.8rem;
  line-height: 1.5;
  color: var(--c-dim);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: clamp(1.75rem, 4vw, 2.5rem) 0 0;
  padding: 0 0 0 1.9rem;
  position: relative;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 0.7rem;
  bottom: 1.6rem;
  width: 1px;
  background: var(--c-line);
}

.page-about .about-timeline > li {
  position: relative;
  padding-bottom: clamp(1.75rem, 4vw, 2.5rem);
}

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

.page-about .about-timeline > li::before {
  content: "";
  position: absolute;
  left: -1.9rem;
  top: 0.55rem;
  width: 9px;
  height: 9px;
  background: var(--c-cyan);
}

.page-about .about-timeline__step {
  margin: 0 0 0.5rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  color: var(--c-cyan);
}

.page-about .about-timeline > li > p {
  max-width: 62ch;
  margin: 0;
  font-size: 0.97rem;
  line-height: 1.72;
  color: var(--c-muted);
}

.page-about .about-timeline details {
  max-width: 62ch;
  margin-top: 0.85rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--c-line);
}

.page-about .about-timeline summary {
  cursor: pointer;
  list-style: none;
  font-family: var(--mono);
  font-size: 0.8rem;
  letter-spacing: 0.05em;
  color: var(--c-cyan);
}

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

.page-about .about-timeline summary::before {
  content: "+ ";
}

.page-about .about-timeline details[open] summary::before {
  content: "– ";
}

.page-about .about-timeline summary:focus-visible {
  outline: 1px solid var(--c-cyan);
  outline-offset: 3px;
}

.page-about .about-timeline details p {
  margin: 0.6rem 0 0;
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--c-dim);
}

/* ---------- 团队三列 ---------- */
.page-about .about-crew {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: clamp(1.25rem, 3vw, 1.75rem) 0 clamp(1.5rem, 4vw, 2rem);
  border: 1px solid var(--c-line);
  background: var(--c-line);
}

.page-about .about-crew__cell {
  background: var(--c-stand);
  padding: clamp(1.25rem, 3vw, 1.75rem);
}

.page-about .about-crew__tag {
  margin: 0 0 0.75rem;
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.16em;
  color: var(--c-cyan);
}

.page-about .about-crew__cell p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--c-muted);
}

/* ---------- 产出节奏 ---------- */
.page-about .about-rhythm {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: clamp(1.5rem, 4vw, 2.25rem);
  border: 1px solid var(--c-line);
  background: var(--c-line);
}

.page-about .about-rhythm__item {
  background: var(--c-night);
  padding: clamp(1.25rem, 3vw, 1.85rem);
}

.page-about .about-rhythm__clock {
  margin: 0 0 0.8rem;
  font-family: var(--mono);
  font-size: clamp(1.05rem, 3vw, 1.4rem);
  letter-spacing: -0.01em;
  color: var(--c-orange);
}

.page-about .about-rhythm__item p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.72;
  color: var(--c-muted);
}

/* ---------- 合作规模数字矩阵 ---------- */
.page-about .about-numbers {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(1.5rem, 4vw, 2.25rem) 0;
  border: 1px solid var(--c-line);
  background: var(--c-line);
}

.page-about .about-numbers__cell {
  background: var(--c-night);
  padding: clamp(1.1rem, 3vw, 1.5rem);
}

.page-about .about-numbers__val {
  margin: 0 0 0.5rem;
  font-family: var(--mono);
  font-size: clamp(1.6rem, 5vw, 2.5rem);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--c-cyan);
}

.page-about .about-numbers__label {
  margin: 0;
  font-size: 0.84rem;
  line-height: 1.6;
  color: var(--c-muted);
}

.page-about .about-coop {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  border: 1px solid var(--c-line);
  background: var(--c-line);
}

.page-about .about-coop__row {
  background: var(--c-stand);
  padding: clamp(1.15rem, 3vw, 1.6rem);
}

.page-about .about-coop__row p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--c-muted);
}

/* ---------- 品牌主张 ---------- */
.page-about .about-motto__lead {
  max-width: none;
  margin: 0 0 1.5rem;
  font-size: clamp(1.8rem, 6vw, 3rem);
  font-weight: 900;
  line-height: 1.06;
  letter-spacing: -0.035em;
  color: var(--c-cyan);
}

/* ---------- 后续入口 ---------- */
.page-about .about-next {
  padding-block: clamp(2.5rem, 7vw, 4.5rem);
  border-top: 1px solid var(--c-line);
}

.page-about .about-cta {
  border: 1px solid var(--c-line);
  padding: clamp(1.5rem, 4.5vw, 2.75rem);
  background: linear-gradient(140deg, var(--c-stand), var(--c-night) 68%);
}

.page-about .about-cta__eyebrow {
  margin: 0 0 0.9rem;
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--c-orange);
}

.page-about .about-cta__title {
  margin: 0 0 1rem;
  max-width: 26ch;
  font-size: clamp(1.5rem, 4.2vw, 2.4rem);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -0.028em;
  color: var(--c-white);
}

.page-about .about-cta__text {
  max-width: 56ch;
  margin: 0 0 clamp(1.5rem, 4vw, 2.25rem);
  font-size: 0.96rem;
  line-height: 1.75;
  color: var(--c-muted);
}

.page-about .about-cta__links {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  border: 1px solid var(--c-line);
  background: var(--c-line);
}

.page-about .about-cta__link {
  display: block;
  padding: 1.05rem 1.15rem;
  background: var(--c-black);
  text-decoration: none;
  transition: background 120ms var(--ease);
}

.page-about .about-cta__link:focus-visible {
  outline: 1px solid var(--c-cyan);
  outline-offset: -2px;
}

.page-about .about-cta__link-title {
  display: block;
  font-size: 1rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--c-white);
  transition: color 120ms var(--ease);
}

.page-about .about-cta__link-desc {
  display: block;
  margin-top: 0.35rem;
  font-size: 0.83rem;
  line-height: 1.55;
  color: var(--c-dim);
}

.page-about .about-cta__link:hover .about-cta__link-title,
.page-about .about-cta__link:focus-visible .about-cta__link-title {
  color: var(--c-cyan);
}

/* ---------- 断点 ---------- */
@media (min-width: 620px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about .about-chapter__grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gutter);
  }

  .page-about .about-chapter__rail {
    position: sticky;
    top: calc(var(--bar-h) + 1.25rem);
  }

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

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

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

@media (min-width: 1120px) {
  .page-about {
    --about-rail: 208px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-jump a,
  .page-about .about-cta__link,
  .page-about .about-cta__link-title {
    transition: none;
  }
}