.page-about {
  --about-rail-w: 120px;
  --about-chap-pad: clamp(52px, 7vw, 92px);
  display: block;
  background: var(--deep);
  color: var(--bone);
  font-family: var(--font-body);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(40px, 6vw, 88px) 0 clamp(32px, 4vw, 56px);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(120% 90% at 88% 0%, rgba(52, 231, 208, 0.09), transparent 58%),
    linear-gradient(180deg, var(--shell) 0%, var(--deep) 100%);
}

.page-about .about-hero__wrap {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 4vw, 40px);
  align-items: end;
}

.page-about .about-crumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 10px;
  list-style: none;
  margin: 0 0 20px;
  padding: 0;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.page-about .about-crumbs li + li::before {
  content: "/";
  margin-right: 10px;
  color: var(--line);
}

.page-about .about-crumbs a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease-out, border-color 0.2s ease-out;
}

.page-about .about-crumbs a:hover,
.page-about .about-crumbs a:focus-visible {
  color: var(--lava);
  border-bottom-color: var(--lava);
}

.page-about .about-hero__notes p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.75;
  color: var(--soft);
  max-width: 62ch;
}

.page-about .about-hero__notes .lede {
  color: var(--bone);
  font-size: clamp(17px, 1.6vw, 21px);
  line-height: 1.62;
}

.page-about .about-hero__acts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 26px 0 0;
}

/* ---------- 规模统计条 ---------- */
.page-about .about-metrics {
  list-style: none;
  margin: clamp(36px, 5vw, 64px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  border-right: 1px solid var(--line);
}

.page-about .about-metric {
  position: relative;
  padding: clamp(18px, 2.4vw, 28px) clamp(12px, 1.6vw, 22px);
  border-left: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  transition: background-color 0.2s ease-out;
}

.page-about .about-metric:hover {
  background: rgba(12, 35, 56, 0.72);
}

.page-about .about-metric__num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(32px, 4.4vw, 52px);
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--cyan);
}

.page-about .about-metric__unit {
  position: relative;
  display: block;
  margin-top: 12px;
  min-height: 3.2em;
  font-size: 12px;
  line-height: 1.6;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.page-about .about-metric__u {
  position: absolute;
  inset: 0;
  transition: opacity 0.2s ease-out;
}

.page-about .about-metric__u--alt {
  opacity: 0;
  color: var(--lava);
}

.page-about .about-metric:hover .about-metric__u--base,
.page-about .about-metric:focus-within .about-metric__u--base {
  opacity: 0;
}

.page-about .about-metric:hover .about-metric__u--alt,
.page-about .about-metric:focus-within .about-metric__u--alt {
  opacity: 1;
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  position: relative;
  padding: var(--about-chap-pad) 0;
}

.page-about .about-chapter:not(:first-of-type) {
  border-top: 1px solid var(--line);
}

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

.page-about .about-chapter__rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .about-chapter__num {
  display: inline-block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(30px, 4.6vw, 52px);
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--mist);
  text-decoration: none;
  transition: color 0.2s ease-out;
}

.page-about .about-chapter__num:hover,
.page-about .about-chapter__num:focus-visible {
  color: var(--lava);
}

.page-about .about-chapter:target .about-chapter__num {
  color: var(--lava);
}

.page-about .about-chapter__rail::after {
  content: "";
  flex: 1 1 auto;
  height: 1px;
  background: var(--line);
}

.page-about .about-chapter__body > p,
.page-about .about-chapter__text > p {
  max-width: 68ch;
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.75;
  color: var(--soft);
}

.page-about .about-chapter__body > p:first-of-type {
  margin-top: 22px;
}

.page-about .about-chapter__body > .chapter-title,
.page-about .about-chapter__text > .chapter-title {
  margin: 0;
}

.page-about .about-chapter__body > .chapter-title + p,
.page-about .about-chapter__text > .chapter-title + p {
  margin-top: 22px;
}

.page-about .about-chapter__more {
  margin: 26px 0 0;
}

/* ---------- 01 三条职责 ---------- */
.page-about .about-role-list {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
  max-width: 76ch;
}

.page-about .about-role-list li {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-role-list__k {
  font-size: 16px;
  font-weight: 700;
  color: var(--bone);
  letter-spacing: 0.02em;
}

.page-about .about-role-list__v {
  font-size: 15px;
  line-height: 1.72;
  color: var(--mist);
}

/* ---------- 02 口径与边界 ---------- */
.page-about .about-chapter--grid {
  overflow: hidden;
  background: linear-gradient(180deg, var(--shell) 0%, var(--deep) 100%);
}

.page-about .about-grid-bg {
  position: absolute;
  top: 0;
  right: 0;
  width: min(58%, 720px);
  margin: 0;
  opacity: 0.16;
  pointer-events: none;
  z-index: 0;
}

.page-about .about-grid-bg img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-chapter--grid .about-chapter__grid {
  position: relative;
  z-index: 1;
}

.page-about .about-bounds {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  max-width: 80ch;
}

.page-about .about-bound {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-bound:first-child {
  border-top: 1px solid var(--line);
}

.page-about .about-bound p {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--soft);
}

/* ---------- 03 覆盖与节奏 ---------- */
.page-about .about-figure {
  margin: 26px 0 0;
}

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

.page-about .about-figure figcaption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
  max-width: 52ch;
}

.page-about .about-figure--band {
  margin: 0 0 30px;
}

.page-about .about-figure--band img {
  aspect-ratio: 7 / 4;
  clip-path: polygon(0 0, 100% 0, 100% 92%, 0 100%);
}

.page-about .about-figure--band figcaption {
  margin-top: 14px;
}

/* ---------- 04 团队 ---------- */
.page-about .about-team {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  max-width: 82ch;
}

.page-about .about-team li {
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-areas:
    "n r"
    "n d";
  column-gap: 18px;
  align-items: baseline;
  padding: 20px;
  background: var(--panel);
}

.page-about .about-team__n {
  grid-area: n;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 34px;
  font-weight: 500;
  line-height: 1;
  color: var(--grass);
  letter-spacing: -0.03em;
}

.page-about .about-team__r {
  grid-area: r;
  font-size: 16px;
  font-weight: 700;
  color: var(--bone);
}

.page-about .about-team__d {
  grid-area: d;
  margin-top: 6px;
  font-size: 14px;
  line-height: 1.68;
  color: var(--mist);
}

/* ---------- 05 版本时间轴 ---------- */
.page-about .about-axis-scroll {
  margin: 30px 0 28px;
  overflow-x: auto;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--panel);
  padding: 12px 8px;
}

.page-about .about-axis {
  display: block;
  width: 100%;
  min-width: 620px;
  height: auto;
}

/* ---------- 继续了解 ---------- */
.page-about .about-next {
  padding: var(--about-chap-pad) 0 calc(var(--about-chap-pad) + 12px);
  border-top: 1px solid var(--line);
  background:
    linear-gradient(180deg, var(--deep) 0%, var(--shell) 100%);
}

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

.page-about .about-next__head h2 {
  margin: 10px 0 0;
  font-size: clamp(24px, 3vw, 36px);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--bone);
}

.page-about .about-next__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-next__list li {
  border-bottom: 1px solid var(--line);
}

.page-about .about-next__list a {
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-areas:
    "idx label"
    "idx desc";
  column-gap: 20px;
  align-items: baseline;
  padding: 22px 4px;
  text-decoration: none;
  color: inherit;
  transition: background-color 0.2s ease-out, transform 0.2s ease-out;
}

.page-about .about-next__list a:hover,
.page-about .about-next__list a:focus-visible {
  background: rgba(255, 90, 31, 0.08);
  transform: translateY(-2px);
}

.page-about .about-next__idx {
  grid-area: idx;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  letter-spacing: 0.18em;
  color: var(--lava);
}

.page-about .about-next__label {
  grid-area: label;
  font-size: 18px;
  font-weight: 700;
  color: var(--bone);
}

.page-about .about-next__desc {
  grid-area: desc;
  margin-top: 6px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 焦点反馈 ---------- */
.page-about a:focus-visible,
.page-about button:focus-visible {
  outline: 2px solid var(--lava);
  outline-offset: 2px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-role-list li {
    grid-template-columns: minmax(0, 3fr) minmax(0, 7fr);
    gap: 28px;
    align-items: baseline;
  }

  .page-about .about-bound {
    grid-template-columns: 92px minmax(0, 1fr);
    gap: 24px;
    align-items: start;
  }

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

  .page-about .about-next__list a {
    grid-template-columns: 64px minmax(0, 1fr) minmax(0, 1.2fr);
    grid-template-areas: "idx label desc";
    column-gap: 28px;
    align-items: center;
  }

  .page-about .about-next__desc {
    margin-top: 0;
  }
}

@media (min-width: 920px) {
  .page-about .about-hero__wrap {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    gap: clamp(40px, 5vw, 88px);
  }

  .page-about .about-metrics {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-chapter__grid {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    column-gap: clamp(28px, 4vw, 72px);
  }

  .page-about .about-chapter__rail {
    position: sticky;
    top: calc(var(--rail-w) + 28px);
    align-self: start;
    display: block;
  }

  .page-about .about-chapter__rail::after {
    display: none;
  }

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

  .page-about .about-chapter--bleed .about-chapter__body {
    display: grid;
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    column-gap: clamp(32px, 4vw, 64px);
    align-items: start;
  }

  .page-about .about-chapter--bleed .about-chapter__text > p {
    max-width: 46ch;
  }

  .page-about .about-chapter--bleed .about-figure {
    margin-top: 4px;
  }

  .page-about .about-chapter--bleed .about-chapter__text .chapter-title + p {
    margin-top: 22px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-figure--band img {
    aspect-ratio: 7 / 3.4;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-metric,
  .page-about .about-metric__u,
  .page-about .about-chapter__num,
  .page-about .about-crumbs a,
  .page-about .about-next__list a {
    transition: none;
  }

  .page-about .about-next__list a:hover,
  .page-about .about-next__list a:focus-visible {
    transform: none;
  }
}