/* ===== 品牌文化 / page-about ===== */
.page-about {
  --ab-edge: 1px solid var(--line-soft);
  --ab-side-w: 280px;
  position: relative;
  background: var(--pitch-void);
  color: var(--chalk-white);
  overflow-x: hidden;
  padding-bottom: clamp(24px, 4vw, 56px);
}

.page-about .ab-block,
.page-about .ab-hero,
.page-about .ab-index {
  min-width: 0;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(20px, 3vw, 40px) clamp(32px, 5vw, 64px);
  border-bottom: var(--ab-edge);
}

.page-about .ab-contour {
  position: absolute;
  left: -6%;
  right: -6%;
  top: -20%;
  height: 140%;
  z-index: 0;
  pointer-events: none;
  opacity: .5;
  background:
    repeating-radial-gradient(circle at 86% 8%,
      rgba(120, 180, 170, .16) 0 1px,
      transparent 1px 42px);
}

.page-about .ab-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 44px);
  min-width: 0;
}

.page-about .ab-hero__text {
  min-width: 0;
}

.page-about .ab-hero__title {
  margin: 14px 0 18px;
  font-family: var(--font-body);
  font-weight: 200;
  font-size: clamp(30px, 7.4vw, 76px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--chalk-white);
}

.page-about .ab-hero__lede {
  max-width: 56ch;
  color: var(--slate-text);
}

.page-about .ab-facts {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  border-top: var(--ab-edge);
}

.page-about .ab-facts li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px 16px;
  padding: 9px 0;
  border-bottom: var(--ab-edge);
  font-size: 13px;
}

.page-about .ab-facts__k {
  color: var(--slate-text);
  letter-spacing: .12em;
  font-size: 11px;
  text-transform: uppercase;
}

.page-about .ab-facts__v {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  color: var(--chalk-white);
}

.page-about .ab-hero__figure {
  margin: 0;
}

/* ---------- 章节索引 ---------- */
.page-about .ab-index {
  padding-block: clamp(16px, 2.4vw, 24px);
  border-bottom: var(--ab-edge);
  background: linear-gradient(180deg, rgba(11, 43, 35, .55), rgba(5, 11, 15, 0));
}

.page-about .ab-index__label {
  margin: 0 0 12px;
  color: var(--amber-warm);
  opacity: .8;
  letter-spacing: .18em;
}

.page-about .ab-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 10px;
}

.page-about .ab-index__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 12px;
  border: 1px solid var(--line-mid);
  background: rgba(15, 30, 28, .5);
  color: var(--chalk-white);
  font-size: 13px;
  line-height: 1.3;
  text-decoration: none;
  transition: border-color var(--t-fast) var(--ease),
              color var(--t-fast) var(--ease),
              background-color var(--t-fast) var(--ease);
}

.page-about .ab-index__link:hover,
.page-about .ab-index__link:focus-visible {
  border-color: var(--signal-cyan);
  background: var(--cyan-soft);
  color: var(--signal-cyan);
  outline: none;
}

.page-about .ab-index__no {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--amber-warm);
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-block {
  position: relative;
}

.page-about .ab-block__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 14px;
  padding-bottom: 12px;
  margin-bottom: clamp(18px, 2.6vw, 30px);
  border-bottom: 1px solid var(--line-mid);
}

.page-about .ab-block__num {
  color: var(--amber-warm);
  opacity: .9;
}

.page-about .ab-block__head h2 {
  margin: 0;
}

.page-about .ab-block__body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 34px);
  align-items: start;
}

.page-about .ab-block__main {
  min-width: 0;
  max-width: 76ch;
}

.page-about .ab-block__side {
  min-width: 0;
  display: grid;
  gap: 16px;
}

/* ---------- 数字条 ---------- */
.page-about .ab-stats {
  list-style: none;
  margin: clamp(22px, 3vw, 34px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .ab-stats li {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px;
  background: var(--panel-paper);
  min-width: 0;
}

.page-about .ab-stat__num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 3.4vw, 36px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--signal-cyan);
}

.page-about .ab-stat__label {
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--slate-text);
}

/* ---------- 图片与卡片 ---------- */
.page-about .media-frame img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ab-figure {
  margin: 0;
}

.page-about .ab-figure--paper {
  background: var(--panel-paper);
  border: 1px solid var(--line-mid);
  box-shadow: 10px 10px 0 rgba(11, 43, 35, .95);
}

.page-about .ab-hero__figure.media-frame--tall img {
  aspect-ratio: 4 / 5;
}

.page-about .media-frame--strip {
  margin-top: clamp(22px, 3.4vw, 38px);
}

.page-about .media-frame--strip img {
  aspect-ratio: 2 / 1;
}

.page-about .ab-note {
  background: linear-gradient(160deg, rgba(11, 43, 35, .95), rgba(15, 30, 28, .95));
  border: 1px solid var(--line-mid);
  padding: clamp(16px, 2vw, 20px);
  min-width: 0;
}

.page-about .ab-note__title {
  margin: 0;
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--amber-warm);
}

.page-about .ab-note--fold {
  padding: 0;
}

.page-about .ab-note__summary {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
  font-size: 13px;
  line-height: 1.5;
  color: var(--signal-cyan);
  transition: background-color var(--t-fast) var(--ease);
}

.page-about .ab-note__summary::-webkit-details-marker {
  display: none;
}

.page-about .ab-note__summary::marker {
  content: "";
}

.page-about .ab-note__summary:hover,
.page-about .ab-note__summary:focus-visible {
  background: var(--cyan-soft);
  outline: none;
}

.page-about .ab-note__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--amber-warm);
}

.page-about .ab-note[open] .ab-note__summary::after {
  content: "–";
}

.page-about .ab-note__body {
  padding: 0 16px 16px;
}

.page-about .ab-note__body p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--slate-text);
}

.page-about .ab-swatches {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  display: grid;
  gap: 9px;
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--slate-text);
}

.page-about .ab-swatches li {
  display: flex;
  align-items: center;
  gap: 10px;
}

.page-about .ab-swatch {
  flex: none;
  width: 10px;
  height: 10px;
  border: 1px solid rgba(244, 246, 242, .22);
}

.page-about .ab-swatch--cyan { background: var(--signal-cyan); }
.page-about .ab-swatch--amber { background: var(--amber-warm); }
.page-about .ab-swatch--pulse { background: var(--pulse-orange); }

/* ---------- 夜场灯光章节 ---------- */
.page-about .ab-block--night {
  overflow: hidden;
  background: linear-gradient(180deg, rgba(11, 43, 35, .42), rgba(5, 11, 15, 0) 70%);
}

.page-about .ab-block--night > .wrap {
  position: relative;
  z-index: 1;
}

.page-about .ab-ridgeline {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: clamp(90px, 14vw, 170px);
  pointer-events: none;
  opacity: .85;
}

.page-about .ab-ridgeline svg {
  display: block;
  width: 100%;
  height: 100%;
}

/* ---------- 版本时间线 ---------- */
.page-about .ab-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 22px;
  position: relative;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 12px;
  bottom: 12px;
  width: 1px;
  background: linear-gradient(180deg,
    var(--signal-cyan) 0%,
    var(--line-mid) 55%,
    rgba(120, 180, 170, 0) 100%);
}

.page-about .ab-timeline > li {
  position: relative;
}

.page-about .ab-timeline > li::before {
  content: "";
  position: absolute;
  left: -16px;
  top: 22px;
  width: 9px;
  height: 9px;
  background: var(--pitch-void);
  border: 1px solid var(--signal-cyan);
}

.page-about .ab-node {
  border-bottom: var(--ab-edge);
}

.page-about .ab-node__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 13px 0;
  cursor: pointer;
  list-style: none;
  transition: color var(--t-fast) var(--ease);
}

.page-about .ab-node__head::-webkit-details-marker {
  display: none;
}

.page-about .ab-node__head::marker {
  content: "";
}

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

.page-about .ab-node__ver {
  flex: none;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: .02em;
  color: var(--amber-warm);
  min-width: 3.4em;
}

.page-about .ab-node__title {
  font-size: 15px;
  line-height: 1.5;
  color: var(--chalk-white);
  transition: color var(--t-fast) var(--ease);
}

.page-about .ab-node__head:hover .ab-node__title,
.page-about .ab-node__head:focus-visible .ab-node__title,
.page-about .ab-node[open] .ab-node__title {
  color: var(--signal-cyan);
}

.page-about .ab-node__mark {
  position: relative;
  flex: none;
  width: 12px;
  height: 12px;
  margin-left: auto;
  align-self: center;
}

.page-about .ab-node__mark::before,
.page-about .ab-node__mark::after {
  content: "";
  position: absolute;
  background: var(--signal-cyan);
}

.page-about .ab-node__mark::before {
  left: 0;
  right: 0;
  top: 50%;
  height: 1px;
}

.page-about .ab-node__mark::after {
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  transition: transform var(--t-base) var(--ease);
}

.page-about .ab-node[open] .ab-node__mark::after {
  transform: scaleY(0);
}

.page-about .ab-node__body {
  max-width: 66ch;
  padding: 0 0 18px;
}

.page-about .ab-node__body p {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--slate-text);
}

/* ---------- 正文细节 ---------- */
.page-about .prose a {
  color: var(--signal-cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--cyan-mid);
  transition: border-color var(--t-fast) var(--ease);
}

.page-about .prose a:hover,
.page-about .prose a:focus-visible {
  border-bottom-color: var(--signal-cyan);
  outline: none;
}

/* ---------- 断点 ---------- */
@media (min-width: 720px) {
  .page-about .ab-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 960px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, .6fr);
    gap: clamp(36px, 5vw, 72px);
  }

  .page-about .ab-hero__figure {
    margin-top: clamp(12px, 4vw, 52px);
  }

  .page-about .ab-block__body {
    grid-template-columns: minmax(0, 1fr) var(--ab-side-w);
    gap: clamp(28px, 4vw, 56px);
  }

  .page-about .ab-block__body--solo {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-about .ab-block__head {
    gap: 18px;
  }
}

@media (min-width: 1320px) {
  .page-about .ab-block__body {
    grid-template-columns: minmax(0, 1fr) 320px;
  }

  .page-about .ab-block__body--solo {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-index__link,
  .page-about .ab-node__head,
  .page-about .ab-node__title,
  .page-about .ab-node__mark::after,
  .page-about .ab-note__summary {
    transition: none;
  }
}
<<<END>>>