.page-about {
  --about-axis-w: 118px;
  --about-line: rgba(30, 110, 122, .38);
}

/* ── 首屏 ───────────────────────────── */
.page-about .about-hero {
  padding-top: clamp(10px, 2vw, 22px);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 5vw, 52px);
}

.page-about h1 {
  margin: 14px 0 0;
  font-size: clamp(36px, 7.4vw, 78px);
  line-height: 1.02;
  letter-spacing: -.02em;
  font-weight: 800;
  max-width: 13em;
}

.page-about .about-hero__lede {
  margin: 24px 0 0;
  max-width: 42ch;
  font-size: clamp(16px, 1.5vw, 19px);
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-hero__note {
  margin: 18px 0 0;
  max-width: 46ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-hero__panel {
  border: 1px solid var(--about-line);
  border-radius: 4px;
  background: var(--glass);
  backdrop-filter: blur(6px);
  padding: 6px;
}

/* ── 通用分栏与标题 ─────────────────── */
.page-about .about-block {
  border-top: 1px solid var(--hair);
}

.page-about .about-split {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: clamp(14px, 2.6vw, 36px);
}

.page-about .about-split__rail {
  position: relative;
}

.page-about .about-split__idx {
  display: block;
  padding-top: 2px;
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--pulse);
}

.page-about .about-split__rail::after {
  content: "";
  position: absolute;
  left: 8px;
  top: 30px;
  bottom: 4px;
  width: 1px;
  background: linear-gradient(180deg, var(--about-line), transparent);
}

.page-about h2 {
  margin: 0 0 18px;
  font-size: clamp(26px, 3.4vw, 40px);
  line-height: 1.18;
  letter-spacing: -.02em;
  font-weight: 800;
  max-width: 17em;
}

.page-about h3 {
  margin: 0 0 10px;
  font-size: 20px;
  line-height: 1.4;
  font-weight: 700;
}

.page-about h4 {
  margin: 0 0 6px;
  font-size: 16px;
  line-height: 1.4;
  font-weight: 700;
  color: var(--pulse);
}

.page-about .about-lead {
  margin: 0 0 26px;
  max-width: 60ch;
  font-size: clamp(16px, 1.45vw, 18px);
  line-height: 1.9;
  color: var(--ink);
}

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

.page-about .media__caption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

/* ── 目录与覆盖度 ───────────────────── */
.page-about .catalog-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3.5vw, 42px);
  margin-top: 6px;
}

.page-about .catalog-cols__fig {
  margin: 0;
}

.page-about .cov {
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .cov__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px 14px;
  align-items: center;
}

.page-about .cov__name {
  font-size: 14px;
  letter-spacing: .04em;
  color: var(--muted);
}

.page-about .cov__val {
  font-size: 14px;
  color: var(--pulse);
}

.page-about .cov__track {
  grid-column: 1 / -1;
  display: block;
  height: 6px;
  border-radius: 999px;
  background: rgba(255, 255, 255, .07);
  overflow: hidden;
}

.page-about .cov__fill {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: 999px;
  background-image: linear-gradient(90deg, var(--lake), var(--pulse), var(--lake));
  background-size: 220% 100%;
  animation: about-flow 7s linear infinite;
}

.page-about .cov__fill--gold {
  background-image: linear-gradient(90deg, var(--wine), var(--gold), var(--wine));
}

@keyframes about-flow {
  from { background-position: 0% 0; }
  to { background-position: 220% 0; }
}

/* ── 团队 ───────────────────────────── */
.page-about .about-team__fig {
  margin: 0 0 clamp(24px, 4vw, 38px);
}

.page-about .team-table tbody tr {
  transition: background-color .25s var(--ease);
}

.page-about .team-table tbody tr:hover,
.page-about .team-table tbody tr:focus-within {
  background: rgba(47, 232, 214, .07);
}

.page-about .steps {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .steps__item {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 14px;
  padding: 18px 16px;
  background: var(--abyss-2);
}

.page-about .steps__no {
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--gold);
}

.page-about .steps__item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

/* ── 版本时间线 ─────────────────────── */
.page-about .tl {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  position: relative;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 39px;
  top: 10px;
  bottom: 14px;
  width: 1px;
  background: linear-gradient(180deg, var(--pulse), rgba(47, 232, 214, .06));
}

.page-about .tl__item {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  padding-left: 68px;
  padding-bottom: 26px;
}

.page-about .tl__item::before {
  content: "";
  position: absolute;
  left: 34px;
  top: 8px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--abyss);
  border: 1px solid var(--pulse);
  box-shadow: 0 0 0 4px rgba(47, 232, 214, .12);
  animation: about-node 3.6s ease-in-out infinite;
}

@keyframes about-node {
  0%, 100% { opacity: .48; }
  50% { opacity: 1; }
}

.page-about .tl__stamp {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.page-about .tl__year {
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 800;
  letter-spacing: -.02em;
  color: var(--ink);
}

.page-about .tl__ver {
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--pulse);
}

.page-about .tl__card {
  border: 1px solid var(--about-line);
  border-radius: 4px;
  background: var(--glass);
  backdrop-filter: blur(4px);
  padding: 18px 20px;
}

.page-about .tl__card p {
  margin: 0;
  max-width: 46ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .fold {
  margin-top: 12px;
}

.page-about .fold__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: 100%;
  padding: 8px 0 0;
  background: none;
  border: 0;
  border-top: 1px solid var(--hair);
  font: inherit;
  font-size: 14px;
  letter-spacing: .04em;
  color: var(--pulse);
  text-align: left;
  cursor: pointer;
}

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

.page-about .fold__sign {
  font-family: var(--mono);
  font-size: 16px;
  line-height: 1;
}

.page-about .fold__body {
  padding-top: 10px;
}

.page-about .fold__body p {
  margin: 0;
  max-width: 48ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink);
}

/* ── 复核节奏 ───────────────────────── */
.page-about .cadence {
  list-style: none;
  margin: 6px 0 0;
  padding: 0;
}

.page-about .cadence__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: 22px 0;
  border-top: 1px solid var(--hair);
}

.page-about .cadence__row:last-child {
  border-bottom: 1px solid var(--hair);
}

.page-about .cadence__when {
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--pulse);
}

.page-about .cadence__what h3 {
  margin-bottom: 8px;
}

.page-about .cadence__what p {
  margin: 0;
  max-width: 56ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

/* ── 收束 ───────────────────────────── */
.page-about .about-outro__fig {
  margin: 0 0 clamp(28px, 4vw, 44px);
}

.page-about .about-outro__body h2 {
  margin-bottom: 14px;
}

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

/* ── 桌面端 ─────────────────────────── */
@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(300px, .9fr);
    align-items: end;
  }

  .page-about .about-hero__panel {
    margin-bottom: 10px;
  }

  .page-about .about-split {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 44px;
  }

  .page-about .catalog-cols {
    grid-template-columns: minmax(0, .92fr) minmax(0, 1.08fr);
    align-items: start;
  }

  .page-about .cadence__row {
    grid-template-columns: 116px minmax(0, 1fr);
    gap: 32px;
    align-items: start;
  }
}

@media (min-width: 860px) {
  .page-about .tl::before {
    left: calc(var(--about-axis-w) - 1px);
  }

  .page-about .tl__item {
    grid-template-columns: var(--about-axis-w) minmax(0, 1fr);
    gap: 30px;
    padding-left: 0;
    padding-bottom: 30px;
  }

  .page-about .tl__item::before {
    left: calc(var(--about-axis-w) - 6px);
  }

  .page-about .tl__stamp {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
    padding-right: 28px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .cov__fill,
  .page-about .tl__item::before {
    animation: none;
  }
}
</main>