/* ===== 品牌档案室 /culture/ ===== */
.page-about {
  --ab-line: rgba(30, 50, 67, 0.9);
  --ab-line-soft: rgba(30, 50, 67, 0.55);
  --ab-paper-line: #D6C8AE;
  --ab-gold-fade: linear-gradient(90deg, rgba(176,138,62,0) 0%, rgba(176,138,62,.72) 14%, rgba(176,138,62,.72) 86%, rgba(176,138,62,0) 100%);
  --ab-rail: 128px;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(48px, 8vw, 104px) 0 clamp(40px, 6vw, 72px);
  background:
    radial-gradient(120% 78% at 86% 0%, rgba(176, 138, 62, 0.16) 0%, rgba(176, 138, 62, 0) 62%),
    linear-gradient(180deg, var(--ink-deep) 0%, var(--ink) 100%);
  border-bottom: 1px solid var(--ab-line);
}
.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.42;
  background-image:
    linear-gradient(rgba(30, 50, 67, 0.6) 1px, transparent 1px),
    linear-gradient(90deg, rgba(30, 50, 67, 0.6) 1px, transparent 1px);
  background-size: 92px 92px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,.95), rgba(0,0,0,0));
  mask-image: linear-gradient(180deg, rgba(0,0,0,.95), rgba(0,0,0,0));
}
.page-about .ab-hero .wrap {
  position: relative;
  z-index: 1;
}
.page-about .ab-kicker {
  margin: clamp(28px, 5vw, 56px) 0 18px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.22em;
  color: var(--gold);
  text-transform: uppercase;
}
.page-about .ab-hero__title {
  margin: 0;
  max-width: 15em;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2.3rem, 7.4vw, 5.4rem);
  line-height: 1.06;
  letter-spacing: -0.01em;
  color: var(--paper-white);
}
.page-about .ab-hero__em {
  color: var(--gold-bright);
  box-shadow: inset 0 -0.16em 0 rgba(196, 73, 58, 0.5);
}
.page-about .ab-hero__lede {
  margin: 26px 0 0;
  max-width: 36em;
  font-size: var(--fs-18);
  line-height: 1.85;
  color: #C6CFD8;
}
.page-about .ab-hero__meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px 20px;
  margin: clamp(34px, 5vw, 56px) 0 0;
  padding-top: 26px;
  border-top: 1px solid var(--ab-line);
}
.page-about .ab-hero__cell dt {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--gray);
}
.page-about .ab-hero__cell dd {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.4rem, 3.4vw, 2.15rem);
  line-height: 1.1;
  color: var(--gold-bright);
}
.page-about .ab-unit {
  margin-left: 6px;
  font-size: var(--fs-14);
  font-weight: 500;
  color: var(--gray);
}

/* ---------- 章节索引条 ---------- */
.page-about .ab-toc {
  background: var(--ink-deep);
  border-bottom: 1px solid var(--ab-line);
}
.page-about .ab-toc__list {
  display: flex;
  flex-wrap: wrap;
  gap: 2px 30px;
  margin: 0;
  padding: 16px 0;
  list-style: none;
}
.page-about .ab-toc__list a {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 6px 0;
  font-size: var(--fs-14);
  color: #9FB0BF;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease);
}
.page-about .ab-toc__idx {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--gold);
}
.page-about .ab-toc__list a:hover,
.page-about .ab-toc__list a:focus-visible {
  color: var(--paper-white);
  border-bottom-color: var(--gold-bright);
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-chapter {
  border-top: 1px solid var(--ab-line-soft);
}
.page-about .ab-chapter--band {
  background: linear-gradient(180deg, rgba(176, 138, 62, 0.06) 0%, rgba(176, 138, 62, 0) 68%);
}
.page-about .ab-chapter--wide {
  background: linear-gradient(180deg, rgba(11, 27, 43, 0.55) 0%, rgba(7, 16, 24, 0.9) 100%);
}
.page-about .ab-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}
.page-about .ab-row__rail {
  display: flex;
  align-items: baseline;
  gap: 12px;
}
.page-about .ab-row__label {
  font-size: var(--fs-14);
  letter-spacing: 0.08em;
  color: var(--gray);
}
.page-about .ab-idx {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: var(--fs-14);
  letter-spacing: 0.18em;
  color: var(--gold);
}
.page-about .ab-row__body {
  min-width: 0;
}
.page-about .ab-h2 {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.6rem, 3.6vw, 2.6rem);
  line-height: 1.24;
  color: var(--paper-white);
  max-width: 18em;
}
.page-about .ab-p {
  margin: 0 0 18px;
  max-width: 40em;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: #B9C4CE;
}
.page-about .ab-note {
  margin: 26px 0 0;
  max-width: 42em;
  padding: 16px 18px;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: #A8B6C2;
  background: rgba(7, 16, 24, 0.6);
  border-left: 2px solid var(--gold);
}
.page-about .ab-note--after {
  margin-top: 32px;
}
.page-about .ab-note a,
.page-about .ab-p a {
  color: var(--gold-bright);
  text-decoration: none;
  border-bottom: 1px solid rgba(216, 178, 94, 0.4);
}
.page-about .ab-note a:hover,
.page-about .ab-p a:hover {
  border-bottom-color: var(--gold-bright);
}

/* ---------- 插画容器 ---------- */
.page-about .ab-fig {
  margin: 32px 0 0;
}
.page-about .ab-fig img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}
.page-about .figure-cap {
  margin-top: 12px;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: var(--gray);
}

/* ---------- 两条主线 ---------- */
.page-about .ab-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  margin-top: 32px;
}
.page-about .ab-split__col {
  padding: 24px 22px 26px;
  background: rgba(7, 16, 24, 0.55);
  border-top: 1px solid var(--ab-line);
  transition: background 0.3s var(--ease);
}
.page-about .ab-split__col--a {
  border-left: 2px solid var(--cinnabar);
}
.page-about .ab-split__col--b {
  border-left: 2px solid var(--jade);
}
.page-about .ab-split__col:hover {
  background: rgba(11, 27, 43, 0.85);
}
.page-about .ab-split__kicker {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  color: var(--gray);
}
.page-about .ab-split__title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.2rem, 2.6vw, 1.5rem);
  color: var(--paper-white);
}
.page-about .ab-split__col p {
  margin: 0 0 16px;
  font-size: var(--fs-16);
  line-height: 1.8;
  color: #B9C4CE;
}
.page-about .ab-list {
  margin: 0;
  padding: 0;
  list-style: none;
}
.page-about .ab-list li {
  position: relative;
  padding: 9px 0 9px 20px;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: #9FB0BF;
  border-top: 1px solid var(--ab-line-soft);
}
.page-about .ab-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 17px;
  width: 6px;
  height: 6px;
  background: var(--gold);
}

/* ---------- 四类归档 ---------- */
.page-about .ab-tree {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  margin-top: 32px;
  border-top: 1px solid var(--ab-line);
}
.page-about .ab-node {
  position: relative;
  padding: 24px 20px 26px;
  border-bottom: 1px solid var(--ab-line);
  transition: background 0.3s var(--ease);
}
.page-about .ab-node:hover {
  background: rgba(176, 138, 62, 0.06);
}
.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: 20px;
  top: -1px;
  width: 0;
  height: 2px;
  background: var(--gold-bright);
  transition: width 0.4s var(--ease);
}
.page-about .ab-node:hover::before {
  width: calc(100% - 40px);
}
.page-about .ab-node__no {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.18em;
  color: var(--gold);
}
.page-about .ab-node__title {
  margin: 10px 0 12px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-18);
  color: var(--paper-white);
}
.page-about .ab-node__text {
  margin: 0 0 16px;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: #A8B6C2;
}
.page-about .ab-node__meta {
  margin: 0;
}
.page-about .ab-node__meta > div {
  display: flex;
  gap: 10px;
  padding: 7px 0;
  border-top: 1px solid var(--ab-line-soft);
}
.page-about .ab-node__meta dt {
  flex: 0 0 42px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--gray);
}
.page-about .ab-node__meta dd {
  margin: 0;
  font-size: var(--fs-12);
  line-height: 1.7;
  color: #9FB0BF;
}

/* ---------- 折叠流程 ---------- */
.page-about .ab-details {
  margin-top: 30px;
  border: 1px solid var(--ab-line);
  background: rgba(7, 16, 24, 0.5);
}
.page-about .ab-details > summary {
  cursor: pointer;
  padding: 16px 20px;
  font-size: var(--fs-16);
  color: var(--gold-bright);
  list-style: none;
}
.page-about .ab-details > summary::-webkit-details-marker {
  display: none;
}
.page-about .ab-details > summary::before {
  content: "＋";
  display: inline-block;
  width: 20px;
  font-family: var(--font-mono);
  color: var(--gold);
}
.page-about .ab-details[open] > summary::before {
  content: "－";
}
.page-about .ab-details > summary:focus-visible {
  outline: 2px solid var(--gold-bright);
  outline-offset: -3px;
  box-shadow: inset 0 0 0 4px rgba(62, 124, 107, 0.35);
}
.page-about .ab-details__body {
  padding: 0 20px 22px;
  border-top: 1px solid var(--ab-line-soft);
}
.page-about .ab-steps {
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}
.page-about .ab-steps li {
  display: grid;
  grid-template-columns: 32px minmax(0, 1fr);
  gap: 14px;
  padding: 13px 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: #A8B6C2;
  border-bottom: 1px solid var(--ab-line-soft);
}
.page-about .ab-steps li:last-child {
  border-bottom: 0;
}
.page-about .ab-steps__no {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  color: var(--cinnabar);
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline {
  margin: 34px 0 0;
  padding: 0;
  list-style: none;
}
.page-about .ab-tl {
  position: relative;
  padding: 20px 0 22px 30px;
  border-left: 1px solid rgba(176, 138, 62, 0.4);
}
.page-about .ab-tl::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 26px;
  width: 7px;
  height: 7px;
  background: var(--cinnabar);
}
.page-about .ab-tl:last-child {
  border-left-color: transparent;
}
.page-about .ab-tl__year {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: var(--fs-18);
  letter-spacing: 0.06em;
  color: var(--gold-bright);
}
.page-about .ab-tl__title {
  margin: 8px 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-16);
  color: var(--paper-white);
}
.page-about .ab-tl p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: #9FB0BF;
}

/* ---------- 团队 ---------- */
.page-about .ab-team {
  margin-top: 30px;
}
.page-about .ab-team .panel {
  height: 100%;
}

/* ---------- 范围与边界（暖纸色阅读区） ---------- */
.page-about .ab-chapter--paper {
  background: var(--paper);
  border-top: 1px solid var(--ab-paper-line);
}
.page-about .ab-idx--paper {
  color: #8A6A26;
}
.page-about .ab-row__label--paper {
  color: #6E6350;
}
.page-about .ab-h2--paper {
  color: var(--ink-deep);
}
.page-about .ab-scope {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  margin-top: 26px;
}
.page-about .ab-scope__col h3 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-18);
  color: var(--ink);
}
.page-about .ab-scope__col h3::after {
  content: "";
  display: block;
  width: 48px;
  height: 2px;
  margin-top: 10px;
  background: var(--cinnabar);
}
.page-about .ab-scope__col:last-child h3::after {
  background: var(--jade);
}
.page-about .ab-list--paper li {
  color: #4A5561;
  border-top: 1px solid var(--ab-paper-line);
}
.page-about .ab-list--paper li::before {
  background: #8A6A26;
}
.page-about .ab-p--paper {
  margin-top: 28px;
  color: #46525E;
}
.page-about .ab-p--paper a {
  color: #8A3A2E;
  border-bottom-color: rgba(138, 58, 46, 0.4);
}

/* ---------- 协作与自查 ---------- */
.page-about .ab-pair {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin-top: 30px;
  border-top: 1px solid var(--ab-line);
}
.page-about .ab-pair__item {
  padding: 22px 0;
  border-bottom: 1px solid var(--ab-line);
}
.page-about .ab-pair__no {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.6rem, 5vw, 2.4rem);
  line-height: 1;
  color: var(--gold-bright);
}
.page-about .ab-pair__label {
  margin: 10px 0 0;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: #9FB0BF;
}

/* ---------- 收束 ---------- */
.page-about .ab-outro {
  background: var(--ink-deep);
  border-top: 1px solid var(--ab-line);
}
.page-about .ab-outro__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  align-items: end;
  padding-bottom: 8px;
}
.page-about .ab-outro__title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.5rem, 3.4vw, 2.2rem);
  line-height: 1.3;
  color: var(--paper-white);
}
.page-about .ab-outro__text {
  margin: 0;
  max-width: 38em;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: #B9C4CE;
}
.page-about .ab-outro__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .ab-hero__meta {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .ab-pair {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .ab-pair__item {
    padding: 22px 20px 22px 0;
    border-bottom: 0;
    border-right: 1px solid var(--ab-line);
  }
  .page-about .ab-pair__item:last-child {
    border-right: 0;
    padding-right: 0;
  }
  .page-about .ab-scope {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 36px;
  }
}

@media (min-width: 900px) {
  .page-about .ab-row {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: 0 48px;
  }
  .page-about .ab-row__rail {
    position: sticky;
    top: calc(var(--header-h) + 32px);
    align-self: start;
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding-top: 6px;
  }
  .page-about .ab-row__label {
    writing-mode: vertical-rl;
    letter-spacing: 0.28em;
    font-size: var(--fs-12);
  }
  .page-about .ab-split {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 36px 40px;
  }
  .page-about .ab-split__col--b {
    margin-top: 76px;
  }
  .page-about .ab-node {
    padding: 26px 22px 28px;
  }
  .page-about .ab-tree {
    grid-template-columns: 1.14fr 1fr 0.92fr 0.8fr;
    border-bottom: 1px solid var(--ab-line);
  }
  .page-about .ab-node {
    border-bottom: 0;
    border-left: 1px solid var(--ab-line);
  }
  .page-about .ab-node:first-child {
    border-left: 0;
  }
  .page-about .ab-timeline {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    border-top: 1px solid rgba(176, 138, 62, 0.4);
  }
  .page-about .ab-tl {
    padding: 30px 20px 6px 0;
    border-left: 0;
  }
  .page-about .ab-tl::before {
    left: 0;
    top: -4px;
    transition: transform 0.3s var(--ease);
  }
  .page-about .ab-tl:hover::before {
    transform: scale(1.6);
  }
  .page-about .ab-tl:last-child {
    padding-right: 0;
  }
  .page-about .ab-outro__inner {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: 40px;
    align-items: center;
  }
  .page-about .ab-outro__actions {
    justify-content: flex-end;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-node::before,
  .page-about .ab-node,
  .page-about .ab-tl::before {
    transition: none;
  }
}