/* ============================================================
   编研使命 / page-about —— 页面专属样式
   ============================================================ */

.page-about {
  --about-rail: 92px;
  --about-gap: 56px;
  background: var(--paper);
  color: var(--ink-950);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  background: var(--paper);
  border-top: 6px solid var(--accent);
  border-bottom: 2px solid var(--ink-950);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  padding-top: 30px;
  padding-bottom: 34px;
}

.page-about .about-hero__title {
  margin: 10px 0 0;
  max-width: 15em;
  font-size: clamp(28px, 8vw, 50px);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -0.02em;
}

.page-about .about-hero__lede {
  margin: 16px 0 0;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-800);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 24px 0 0;
  padding: 2px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px;
  background: var(--ink-950);
  border: 2px solid var(--ink-950);
}

.page-about .about-hero__stats li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 10px 12px 12px;
  background: var(--paper-3);
}

.page-about .about-hero__num {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
  color: var(--ink-900);
}

.page-about .about-hero__key {
  font-size: 12px;
  line-height: 1.5;
  color: var(--muted);
}

.page-about .about-hero__fig {
  margin: 0;
  border: 2px solid var(--ink-950);
  background: var(--paper-2);
  box-shadow: var(--shadow-hard);
}

.page-about .about-hero__fig img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 7;
  object-fit: cover;
  filter: saturate(0.72) contrast(1.1);
}

.page-about .about-hero__fig .fig__cap {
  display: block;
  padding: 9px 10px 10px;
  border-top: 2px solid var(--ink-950);
  background: var(--paper-3);
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.6;
  color: var(--muted);
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(260px, 0.62fr);
    gap: 52px;
    align-items: start;
    padding-top: 56px;
    padding-bottom: 64px;
  }

  .page-about .about-hero__fig img {
    aspect-ratio: 3 / 4;
  }
}

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

/* ---------- 正文双列骨架 ---------- */

.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding-top: 26px;
  padding-bottom: 60px;
}

.page-about .about-toc {
  order: -1;
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-toc__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-toc__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border: 2px solid var(--ink-950);
  background: var(--paper-3);
  color: var(--ink-950);
  font-size: 12px;
  text-decoration: none;
  white-space: nowrap;
  transition: background var(--t) var(--ease), color var(--t) var(--ease);
}

.page-about .about-toc__num {
  font-family: var(--font-mono);
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  color: var(--muted);
}

.page-about .about-toc__link:hover,
.page-about .about-toc__link:focus-visible {
  background: var(--accent);
}

.page-about .about-toc__link:hover .about-toc__num,
.page-about .about-toc__link:focus-visible .about-toc__num {
  color: var(--ink-900);
}

@media (min-width: 900px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
    padding-top: 48px;
    padding-bottom: 96px;
  }

  .page-about .about-toc {
    position: sticky;
    top: calc(var(--cmd-h) + 20px);
    order: 0;
  }

  .page-about .about-toc__list {
    flex-direction: column;
    gap: 16px;
    padding-bottom: 0;
    overflow: visible;
  }

  .page-about .about-toc__link {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    padding: 0;
    border: 0;
    background: transparent;
  }

  .page-about .about-toc__label {
    writing-mode: vertical-rl;
    letter-spacing: 0.18em;
    line-height: 1;
    font-size: 12px;
    color: var(--muted);
  }

  .page-about .about-toc__link:hover .about-toc__label,
  .page-about .about-toc__link:focus-visible .about-toc__label {
    color: var(--ink-950);
  }
}

/* ---------- 章节 ---------- */

.page-about .about-sec {
  padding: 34px 0;
  border-top: 2px solid var(--ink-950);
  scroll-margin-top: calc(var(--cmd-h) + 24px);
}

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

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

.page-about .about-sec__head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.page-about .about-sec__idx {
  flex: none;
  padding: 2px 6px;
  border: 2px solid var(--ink-950);
  background: var(--accent);
  color: var(--ink-900);
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 700;
  line-height: 1.3;
}

.page-about .about-sec__title {
  margin: 0;
  font-size: clamp(21px, 4.2vw, 29px);
  font-weight: 900;
  line-height: 1.28;
  letter-spacing: -0.02em;
}

.page-about .prose {
  margin: 0 0 14px;
  max-width: 40em;
  font-size: 15px;
  line-height: 1.8;
}

.page-about .prose:last-child {
  margin-bottom: 0;
}

.page-about .about-sec a {
  color: var(--ink-900);
  text-decoration: underline;
  text-decoration-color: var(--blue);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.page-about .sub-title {
  margin: 22px 0 12px;
  font-size: 15px;
  font-weight: 900;
  letter-spacing: 0.01em;
}

.page-about .spec {
  display: block;
  margin: 18px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 对比双栏 ---------- */

.page-about .duo {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin: 18px 0 0;
}

.page-about .duo__box {
  padding: 14px;
  border: 2px solid var(--ink-950);
  background: var(--paper-3);
}

.page-about .duo__box--alt {
  background: var(--paper-2);
}

.page-about .duo__title {
  margin: 0 0 10px;
  font-size: 15px;
  font-weight: 900;
  letter-spacing: 0.01em;
}

.page-about .duo__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .duo__list li {
  position: relative;
  padding-left: 15px;
  font-size: 13.5px;
  line-height: 1.7;
}

.page-about .duo__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 6px;
  height: 6px;
  background: var(--accent);
  border: 1px solid var(--ink-950);
}

.page-about .duo__box--alt .duo__list li::before {
  background: var(--blue);
}

@media (min-width: 760px) {
  .page-about .duo {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px;
  }
}

/* ---------- 四步流程 ---------- */

.page-about .flow {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .flow__step {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 20px 14px 16px;
  border: 2px solid var(--ink-950);
  background: var(--paper-3);
  box-shadow: var(--shadow-hard-sm);
}

.page-about .flow__step::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: var(--accent);
}

.page-about .flow__step:nth-child(2)::before {
  background: var(--blue);
}

.page-about .flow__step:nth-child(3)::before {
  background: var(--ink-800);
}

.page-about .flow__step:nth-child(4)::before {
  background: var(--ink-950);
}

.page-about .flow__idx {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .flow__title {
  margin: 0;
  font-size: 17px;
  font-weight: 900;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

.page-about .flow__meta {
  margin: 0;
  display: grid;
  gap: 6px;
}

.page-about .flow__row {
  display: grid;
  grid-template-columns: 3em minmax(0, 1fr);
  gap: 6px;
  font-size: 13px;
  line-height: 1.65;
}

.page-about .flow__row dt {
  font-family: var(--font-mono);
  color: var(--muted);
}

.page-about .flow__row dd {
  margin: 0;
}

.page-about .flow__arrow {
  display: none;
}

@media (min-width: 860px) {
  .page-about .flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 34px;
  }

  .page-about .flow__arrow {
    display: block;
    position: absolute;
    top: 30px;
    right: -33px;
    line-height: 0;
    color: var(--ink-950);
  }

  .page-about .flow__step:last-child .flow__arrow {
    display: none;
  }
}

/* ---------- 分档区间 ---------- */

.page-about .bins {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  border: 2px solid var(--ink-950);
  box-shadow: var(--shadow-hard-sm);
}

.page-about .bins__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 12px 14px;
  background: var(--paper-3);
  border-bottom: 2px solid var(--ink-950);
}

.page-about .bins__row:last-child {
  border-bottom: 0;
}

.page-about .bins__row:nth-child(even) {
  background: var(--paper-2);
}

.page-about .bins__range {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--ink-900);
}

.page-about .bins__desc {
  font-size: 13.5px;
  line-height: 1.7;
}

@media (min-width: 640px) {
  .page-about .bins__row {
    grid-template-columns: 150px minmax(0, 1fr);
    gap: 14px;
    align-items: baseline;
  }
}

.page-about .reads {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 9px;
  max-width: 40em;
}

.page-about .reads li {
  display: grid;
  grid-template-columns: 22px minmax(0, 1fr);
  gap: 10px;
  font-size: 13.5px;
  line-height: 1.7;
}

.page-about .reads__n {
  display: block;
  height: 20px;
  line-height: 20px;
  text-align: center;
  background: var(--ink-900);
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 11px;
}

/* ---------- 复核章节 ---------- */

.page-about .review-fig {
  margin: 0 0 20px;
  border: 2px solid var(--ink-950);
  background: var(--paper-2);
}

.page-about .review-fig img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 7 / 4;
  object-fit: cover;
  filter: saturate(0.7) contrast(1.12);
}

.page-about .review-fig .fig__cap {
  display: block;
  padding: 9px 10px 10px;
  border-top: 2px solid var(--ink-950);
  background: var(--paper-3);
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.6;
  color: var(--muted);
}

/* ---------- 版本演进 ---------- */

.page-about .vers-band {
  margin: 20px 0 4px;
  border: 2px solid var(--ink-950);
  background: var(--ink-900);
}

.page-about .vers-band img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 7;
  object-fit: cover;
  opacity: 0.72;
  filter: saturate(0.6) contrast(1.14);
}

.page-about .vers {
  list-style: none;
  position: relative;
  margin: 22px 0 0;
  padding: 0;
}

.page-about .vers::before {
  content: "";
  position: absolute;
  left: 13px;
  top: 14px;
  bottom: 14px;
  width: 2px;
  background: var(--paper-2);
}

.page-about .vers__item {
  position: relative;
  padding-left: 42px;
  margin-bottom: 14px;
}

.page-about .vers__item:last-child {
  margin-bottom: 0;
}

.page-about .vers__item::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 13px;
  width: 16px;
  height: 16px;
  border: 2px solid var(--ink-950);
  background: var(--paper-3);
}

.page-about .vers__item--a::before {
  background: var(--accent);
}

.page-about .vers__item--b::before {
  background: var(--blue);
}

.page-about .vers__item--c::before {
  background: var(--ink-800);
}

.page-about .vers__item--d::before {
  background: var(--ink-950);
}

.page-about .vers__node {
  border: 2px solid var(--ink-950);
  background: var(--paper-3);
  box-shadow: var(--shadow-hard-sm);
}

.page-about .vers__trigger {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 11px 12px;
  border: 0;
  background: transparent;
  color: var(--ink-950);
  font-family: var(--font-sans);
  text-align: left;
  cursor: pointer;
}

.page-about .vers__ver {
  flex: none;
  padding: 2px 7px;
  background: var(--ink-900);
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  line-height: 1.5;
}

.page-about .vers__name {
  flex: 1 1 auto;
  font-size: 14.5px;
  font-weight: 900;
  line-height: 1.5;
  letter-spacing: -0.01em;
}

.page-about .vers__panel {
  padding: 0 12px 12px;
}

.page-about .vers__facts {
  margin: 0;
  display: grid;
  gap: 6px;
  border-top: 2px dashed var(--paper-2);
  padding-top: 8px;
}

.page-about .vers__fact {
  display: grid;
  grid-template-columns: 3.2em minmax(0, 1fr);
  gap: 8px;
  font-size: 13px;
  line-height: 1.7;
}

.page-about .vers__fact dt {
  font-family: var(--font-mono);
  color: var(--muted);
}

.page-about .vers__fact dd {
  margin: 0;
}

/* ---------- 团队分工 ---------- */

.page-about .team-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 18px 0 0;
}

.page-about .team-card {
  padding: 14px 12px;
  border: 2px solid var(--ink-950);
  background: var(--paper-3);
}

.page-about .team-card:nth-child(2) {
  background: var(--paper-2);
}

.page-about .team-card__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--ink-900);
}

.page-about .team-card__label {
  display: block;
  margin-top: 8px;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--muted);
}

@media (min-width: 760px) {
  .page-about .team-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 14px;
  }
}

/* ---------- 引用规范 ---------- */

.page-about .cite {
  padding: 20px 18px;
  border: 2px solid var(--ink-950);
  background: var(--paper-3);
  box-shadow: var(--shadow-hard);
}

.page-about .cite__lead {
  margin: 0;
  max-width: 34em;
  font-size: 14.5px;
  line-height: 1.8;
}

.page-about .cite__format {
  margin: 14px 0;
  padding: 12px 14px;
  border: 2px solid var(--ink-950);
  background: var(--paper-2);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.9;
  word-break: break-word;
}

.page-about .cite__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .cite__list li {
  position: relative;
  padding-left: 15px;
  font-size: 13.5px;
  line-height: 1.7;
}

.page-about .cite__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 6px;
  height: 6px;
  background: var(--ink-950);
}

@media (min-width: 700px) {
  .page-about .cite {
    padding: 26px 28px;
  }
}