/* ============================================================
   品牌与资料口径 · /brand/ · page-about
   ============================================================ */

.page-about {
  --about-rail: 232px;
  --about-flow-pad: clamp(16px, 3vw, 30px);
  --about-dot: 8px;
  display: block;
  padding-bottom: clamp(48px, 8vw, 96px);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: clamp(20px, 4vw, 40px) 0 clamp(28px, 5vw, 56px);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(22px, 4vw, 44px);
  align-items: end;
}

.page-about .about-hero__copy h1 {
  margin: 0;
  font-size: clamp(2rem, 5.4vw, 3.15rem);
  line-height: 1.24;
  letter-spacing: -0.01em;
}

.page-about .about-lede {
  margin: 0;
  max-width: 48ch;
  font-size: 1rem;
  line-height: 1.92;
  color: var(--gray-400);
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 18px;
  margin: 6px 0 0;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.page-about .about-facts dt {
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--gray-400);
}

.page-about .about-facts dd {
  margin: 0;
  font-family: var(--font-head);
  font-size: clamp(1.05rem, 2.4vw, 1.3rem);
  font-weight: 600;
  color: var(--copper-light);
}

.page-about .about-hero__figure {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  overflow: hidden;
  background: linear-gradient(150deg, var(--ink-800), var(--ink-900));
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  opacity: 0.88;
}

.page-about .about-hero__figure .media__caption {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  justify-content: space-between;
  padding: 12px 16px 14px;
  border-top: 1px solid var(--line-soft);
  background: rgba(11, 22, 34, 0.55);
  font-size: 13px;
  line-height: 1.6;
  color: var(--gray-400);
}

/* ---------- 主体：年份轴 + 内容流 ---------- */

.page-about .about-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 4vw, 44px);
  padding-top: clamp(30px, 5vw, 60px);
}

.page-about .year-rail {
  padding: 18px 16px 16px;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--paper);
}

.page-about .year-rail__list {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
}

.page-about .year-rail__item {
  border-bottom: 1px dashed var(--line-soft);
}

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

.page-about .year-rail__btn {
  display: flex;
  width: 100%;
  align-items: baseline;
  gap: 10px;
  padding: 11px 2px;
  border: 0;
  background: none;
  color: var(--gray-400);
  font-family: var(--font-body);
  font-size: 14px;
  line-height: 1.5;
  text-align: left;
  cursor: pointer;
  transition: color var(--dur-2) var(--ease);
}

.page-about .year-rail__btn:hover {
  color: var(--ivory);
}

.page-about .year-rail__btn:focus-visible {
  outline: 1px solid var(--copper);
  outline-offset: 2px;
  border-radius: var(--r-sm);
}

.page-about .year-rail__btn[aria-expanded="true"] {
  color: var(--copper);
}

.page-about .year-rail__year {
  flex: none;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
}

.page-about .year-rail__stage {
  font-size: 13px;
}

.page-about .year-rail__panel {
  padding: 0 2px 12px;
}

.page-about .year-rail__panel p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--gray-400);
}

.page-about .year-rail__note {
  margin: 6px 0 14px;
  padding-top: 12px;
  border-top: 1px solid var(--line-soft);
  font-size: 12px;
  line-height: 1.7;
}

.page-about .year-rail .btn {
  width: 100%;
  justify-content: center;
}

/* ---------- 贯穿细线 ---------- */

.page-about .about-flow {
  position: relative;
  display: grid;
  gap: clamp(34px, 5vw, 64px);
  padding-left: var(--about-flow-pad);
  border-left: 1px solid var(--line);
  min-width: 0;
}

.page-about .about-flow > .section {
  position: relative;
  min-width: 0;
}

.page-about .about-flow > .section::before {
  content: "";
  position: absolute;
  top: 11px;
  left: calc(-1 * var(--about-flow-pad));
  width: var(--about-dot);
  height: var(--about-dot);
  margin-left: calc(var(--about-dot) / -2);
  border-radius: 50%;
  background: var(--copper);
}

.page-about .section__head {
  max-width: 62ch;
}

.page-about .section__lead {
  color: var(--gray-400);
}

.page-about .prose p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.95;
  color: var(--gray-400);
}

.page-about .prose-note {
  margin: 16px 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--line);
  font-size: 14px;
  line-height: 1.85;
  color: var(--gray-400);
}

/* ---------- 入库 / 当期 卡片 ---------- */

.page-about .principle-grid {
  margin-top: 22px;
}

.page-about .principle-grid .card__meta {
  color: var(--copper);
  letter-spacing: 0.08em;
}

.page-about .principle-grid .card__body {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--gray-400);
}

/* ---------- 三层口径 ---------- */

.page-about .layer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-top: 22px;
}

.page-about .layer-card {
  padding: 20px 18px 22px;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background:
    linear-gradient(180deg, rgba(192, 139, 62, 0.07), rgba(192, 139, 62, 0) 52%),
    var(--ink-800);
}

.page-about .layer-card__no {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--copper);
}

.page-about .layer-card h3 {
  margin: 0 0 8px;
  font-size: 1.05rem;
  line-height: 1.5;
  color: var(--ivory);
}

.page-about .layer-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--gray-400);
}

.page-about .cite {
  margin-top: 16px;
  padding: 16px 18px;
  border-left: 3px solid var(--copper);
  border-radius: 0 var(--r-md) var(--r-md) 0;
  background: rgba(192, 139, 62, 0.08);
}

.page-about .cite p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--ivory);
}

.page-about .cite .code {
  color: var(--copper-light);
}

/* ---------- 编号规则 ---------- */

.page-about .data-table caption {
  padding: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-align: left;
  color: var(--gray-400);
}

.page-about .data-table a {
  color: var(--copper-light);
  text-decoration: none;
  border-bottom: 1px solid rgba(216, 195, 154, 0.32);
}

.page-about .data-table a:hover {
  color: var(--copper);
}

.page-about .code-svg {
  display: block;
  width: 100%;
  height: auto;
  margin: 26px 0 6px;
  overflow: visible;
}

.page-about .code-svg rect {
  fill: rgba(27, 53, 80, 0.72);
  stroke: var(--line);
  stroke-width: 1;
  transition: fill var(--dur-2) var(--ease), stroke var(--dur-2) var(--ease);
}

.page-about .code-svg g:hover rect {
  fill: rgba(192, 139, 62, 0.24);
  stroke: var(--copper);
}

.page-about .code-svg text {
  font-family: var(--font-mono);
  font-size: 20px;
  fill: var(--ivory);
  text-anchor: middle;
}

.page-about .code-svg .code-svg__label {
  font-family: var(--font-body);
  font-size: 12px;
  fill: var(--gray-400);
}

.page-about .code-svg .code-svg__foot {
  font-family: var(--font-body);
  font-size: 11px;
  fill: var(--gray-400);
  text-anchor: start;
}

.page-about .about-figure {
  margin: 22px 0 0;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
  background: var(--ink-800);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  opacity: 0.9;
}

.page-about .about-figure--wide img {
  aspect-ratio: 14 / 9;
}

.page-about .about-figure .media__caption {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  justify-content: space-between;
  padding: 12px 16px 14px;
  border-top: 1px solid var(--line-soft);
  font-size: 13px;
  line-height: 1.6;
  color: var(--gray-400);
}

/* ---------- 时间线 ---------- */

.page-about .timeline {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .timeline__item {
  position: relative;
  padding: 0 0 20px 18px;
  border-left: 1px solid var(--line);
  min-width: 0;
}

.page-about .timeline__item::after {
  content: "";
  position: absolute;
  top: 7px;
  left: -4.5px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--copper);
}

.page-about .timeline__node {
  display: block;
  width: 100%;
  padding: 0 0 8px;
  border: 0;
  background: none;
  color: var(--ivory);
  font-family: inherit;
  text-align: left;
  cursor: pointer;
}

.page-about .timeline__node:focus-visible {
  outline: 1px solid var(--copper);
  outline-offset: 3px;
  border-radius: var(--r-sm);
}

.page-about .timeline__year {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--copper);
}

.page-about .timeline__stage {
  display: block;
  font-family: var(--font-head);
  font-size: 1.05rem;
  font-weight: 600;
  line-height: 1.5;
  transition: color var(--dur-2) var(--ease);
}

.page-about .timeline__node:hover .timeline__stage {
  color: var(--copper-light);
}

.page-about .timeline__node[aria-expanded="true"] .timeline__stage {
  color: var(--copper-light);
}

.page-about .timeline__panel {
  padding: 0;
}

.page-about .timeline__panel p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.82;
  color: var(--gray-400);
}

/* ---------- 复核与分工 ---------- */

.page-about .duty-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-top: 22px;
}

.page-about .duty-card {
  padding: 18px 18px 20px;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--ink-800);
}

.page-about .duty-card__num {
  margin: 0;
  font-family: var(--font-head);
  font-size: 2.1rem;
  font-weight: 700;
  line-height: 1.1;
  color: var(--copper);
}

.page-about .duty-card__label {
  margin: 8px 0 10px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--ivory);
}

.page-about .duty-card__body {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--gray-400);
}

.page-about .duty-steps {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .duty-steps li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  padding: 12px 14px;
  border: 1px dashed var(--line-soft);
  border-radius: var(--r-md);
  font-size: 14px;
  line-height: 1.8;
  color: var(--gray-400);
}

.page-about .duty-steps .code {
  color: var(--copper);
  font-size: 12px;
}

.page-about .duty-steps strong {
  color: var(--ivory);
  font-weight: 600;
}

/* ---------- 结尾 ---------- */

.page-about .section--end .cluster {
  margin-top: 20px;
}

.page-about .about-signoff {
  margin: 22px 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--line-soft);
  font-size: 13.5px;
  line-height: 1.85;
  max-width: 58ch;
}

/* ---------- 响应式 ---------- */

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

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

@media (min-width: 720px) {
  .page-about .layer-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
  }

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

  .page-about .timeline__item {
    padding: 32px 22px 0 0;
    border-left: 0;
  }

  .page-about .timeline__item::before {
    content: "";
    position: absolute;
    top: 14px;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--line);
  }

  .page-about .timeline__item::after {
    top: 10.5px;
    left: 0;
    margin-left: 0;
  }

  .page-about .timeline__item:last-child {
    padding-right: 0;
  }
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    align-items: start;
    gap: clamp(32px, 4vw, 56px);
  }

  .page-about .year-rail {
    position: sticky;
    top: calc(var(--masthead-h) + 22px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .year-rail__btn,
  .page-about .timeline__stage,
  .page-about .code-svg rect {
    transition: none;
  }
}