/* ===== 品牌档案页 · page-about ===== */

.page-about {
  --ab-ink: var(--text-100);
  --ab-muted: var(--text-400);
  --ab-hair: var(--line-600);
  color: var(--text-100);
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding-block: 48px 64px;
  border-bottom: 1px solid var(--line-600);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(201, 162, 39, 0.09) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(201, 162, 39, 0.09) 1px, transparent 1px);
  background-size: 72px 72px;
  -webkit-mask-image: radial-gradient(circle at 76% 24%, #000 0%, transparent 72%);
  mask-image: radial-gradient(circle at 76% 24%, #000 0%, transparent 72%);
  pointer-events: none;
}

.page-about .ab-hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 40px;
}

.page-about .ab-h1 {
  margin: 16px 0 0;
  font-size: clamp(30px, 7.2vw, 62px);
  line-height: 1.12;
  font-weight: 900;
  letter-spacing: -0.025em;
  color: var(--text-100);
}

.page-about .ab-h1-mark {
  color: var(--brand-500);
  box-shadow: inset 0 -0.16em 0 rgba(201, 162, 39, 0.28);
}

.page-about .ab-hero-lead {
  margin: 22px 0 0;
  max-width: 42ch;
  font-size: 15px;
  line-height: 1.9;
  color: var(--text-400);
}

.page-about .ab-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-600);
  border: 1px solid var(--line-600);
  margin-top: 32px;
}

.page-about .ab-fact {
  display: flex;
  flex-direction: column;
  gap: 6px;
  background: var(--base-900);
  padding: 16px 14px 18px;
}

.page-about .ab-fact-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--brand-500);
}

.page-about .ab-fact-unit {
  font-size: 12px;
  font-weight: 400;
  color: var(--text-400);
  margin-left: 4px;
  letter-spacing: 0.08em;
}

.page-about .ab-fact-label {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--text-400);
}

.page-about .ab-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.page-about .ab-hero-actions .btn {
  flex: 0 0 auto;
}

/* 首屏右侧刻度视觉（纯 CSS） */

.page-about .ab-hero-visual {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 240px;
  padding: 18px;
  border: 1px solid var(--line-600);
  background:
    repeating-linear-gradient(90deg, transparent 0 15px, rgba(201, 162, 39, 0.1) 15px 16px),
    linear-gradient(160deg, rgba(201, 162, 39, 0.07), transparent 62%),
    var(--base-800);
}

.page-about .ab-hero-visual-tag,
.page-about .ab-hero-visual-ver {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--text-400);
}

.page-about .ab-hero-visual-ver {
  align-self: flex-end;
  color: var(--brand-500);
}

.page-about .ab-hero-visual-axis {
  display: flex;
  align-items: flex-end;
  gap: 6px;
  height: 130px;
  padding-block: 8px;
  border-bottom: 1px solid var(--brand-500);
}

.page-about .ab-hero-visual-axis i {
  flex: 1 1 0;
  height: 30%;
  background: linear-gradient(to top, rgba(201, 162, 39, 0.55), rgba(201, 162, 39, 0.04));
}

.page-about .ab-hero-visual-axis i:nth-child(2n) { height: 58%; }
.page-about .ab-hero-visual-axis i:nth-child(3n) {
  height: 92%;
  background: linear-gradient(to top, var(--brand-500), rgba(201, 162, 39, 0.08));
}
.page-about .ab-hero-visual-axis i:nth-child(5n) { height: 44%; }
.page-about .ab-hero-visual-axis i:nth-child(7n) { height: 74%; }
.page-about .ab-hero-visual-axis i:nth-child(11n) {
  height: 100%;
  background: linear-gradient(to top, var(--brand-300), rgba(232, 206, 122, 0.1));
}

/* ---------- 通用区块 ---------- */

.page-about .ab-section {
  padding-block: 56px;
  border-top: 1px solid var(--line-600);
}

.page-about .ab-section:first-of-type {
  border-top: 0;
}

.page-about .ab-h2 {
  margin: 12px 0 0;
  font-size: clamp(23px, 4.4vw, 36px);
  font-weight: 800;
  line-height: 1.28;
  letter-spacing: -0.015em;
  color: var(--text-100);
}

.page-about .ab-lead {
  margin: 14px 0 0;
  max-width: 54ch;
  font-size: 15px;
  line-height: 1.9;
  color: var(--text-400);
}

.page-about .ab-chapter {
  display: grid;
  gap: 18px;
}

.page-about .ab-chapter-index span {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 64px;
  font-weight: 700;
  line-height: 0.86;
  color: var(--line-600);
  transition: color var(--dur-cut) var(--ease-cut);
}

.page-about .ab-chapter:hover .ab-chapter-index span {
  color: var(--brand-500);
}

/* ---------- 时间轴 ---------- */

.page-about .ab-tl-figure {
  margin: 30px 0 0;
  border: 1px solid var(--line-600);
  overflow: hidden;
}

.page-about .ab-tl-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ab-tl {
  list-style: none;
  margin: 40px 0 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .ab-tl-item {
  position: relative;
  padding: 28px 0 24px;
  border-top: 1px solid var(--line-600);
}

.page-about .ab-tl-item::before {
  content: "";
  position: absolute;
  top: -5px;
  left: 0;
  width: 9px;
  height: 9px;
  background: var(--brand-500);
  transition: background var(--dur-cut) var(--ease-cut);
}

.page-about .ab-tl-item:has(.ab-tl-details[open])::before {
  background: var(--brand-300);
}

.page-about .ab-tl-details > summary {
  display: block;
  cursor: pointer;
  list-style: none;
}

.page-about .ab-tl-details > summary::-webkit-details-marker {
  display: none;
}

.page-about .ab-tl-year {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--brand-500);
}

.page-about .ab-tl-phase {
  display: block;
  margin-top: 6px;
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--text-400);
}

.page-about .ab-tl-name {
  display: block;
  margin-top: 10px;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-100);
  transition: color var(--dur-cut) var(--ease-cut);
}

.page-about .ab-tl-details > summary::after {
  content: "＋ 展开说明";
  display: inline-block;
  margin-top: 10px;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--brand-500);
}

.page-about .ab-tl-details[open] > summary::after {
  content: "－ 收起";
}

.page-about .ab-tl-details[open] .ab-tl-name {
  color: var(--brand-300);
}

.page-about .ab-tl-details p {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--text-400);
  border-left: 1px solid var(--brand-500);
  padding-left: 14px;
}

/* ---------- 01 日常工作 ---------- */

.page-about .ab-work-grid {
  display: grid;
  gap: 1px;
  background: var(--line-600);
  border: 1px solid var(--line-600);
  margin-top: 28px;
}

.page-about .ab-work {
  background: var(--base-900);
  padding: 22px 18px 24px;
  transition: background var(--dur-cut) var(--ease-cut);
}

.page-about .ab-work:hover {
  background: var(--base-800);
}

.page-about .ab-work-idx {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--brand-500);
}

.page-about .ab-work h3 {
  margin: 10px 0 0;
  font-size: 17px;
  font-weight: 700;
  color: var(--text-100);
}

.page-about .ab-work p {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--text-400);
}

/* ---------- 02 团队 ---------- */

.page-about .ab-team {
  display: grid;
  gap: 34px;
  margin-top: 24px;
}

.page-about .ab-team-copy p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.9;
  color: var(--text-400);
  max-width: 52ch;
}

.page-about .ab-team-note {
  margin-top: 22px;
  border-left: 2px solid var(--accent-600);
  padding: 12px 0 12px 16px;
  background: linear-gradient(90deg, rgba(139, 30, 45, 0.16), transparent);
}

.page-about .ab-team-note-key {
  display: block;
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--brand-300);
}

.page-about .ab-team-note-val {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.8;
  color: var(--text-400);
}

.page-about .ab-team-visual {
  display: grid;
  gap: 22px;
  justify-items: start;
}

.page-about .ab-ring {
  position: relative;
  width: 168px;
  height: 168px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: conic-gradient(
    var(--brand-500) 0deg 140deg,
    var(--chart-teal) 140deg 260deg,
    var(--accent-600) 260deg 360deg
  );
}

.page-about .ab-ring::after {
  content: "";
  position: absolute;
  inset: 24px;
  border-radius: 50%;
  background: var(--base-900);
}

.page-about .ab-ring-center {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  line-height: 1;
}

.page-about .ab-ring-center b {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 34px;
  font-weight: 700;
  color: var(--text-100);
}

.page-about .ab-ring-center small {
  margin-top: 6px;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--text-400);
}

.page-about .ab-legend {
  list-style: none;
  margin: 0;
  padding: 0;
  width: 100%;
  max-width: 300px;
  display: grid;
  gap: 1px;
  background: var(--line-600);
  border: 1px solid var(--line-600);
}

.page-about .ab-legend li {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--base-900);
  padding: 10px 12px;
}

.page-about .ab-swatch {
  width: 10px;
  height: 10px;
  flex: 0 0 auto;
}

.page-about .ab-swatch--brand { background: var(--brand-500); }
.page-about .ab-swatch--teal { background: var(--chart-teal); }
.page-about .ab-swatch--accent { background: var(--accent-600); }

.page-about .ab-legend-name {
  flex: 1 1 auto;
  font-size: 13px;
  color: var(--text-400);
  letter-spacing: 0.06em;
}

.page-about .ab-legend b {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 15px;
  color: var(--brand-300);
}

.page-about .ab-team-figure {
  margin: 0;
  width: 100%;
  border: 1px solid var(--line-600);
  overflow: hidden;
}

.page-about .ab-team-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 03 版本对比带 ---------- */

.page-about .ab-section--band {
  background:
    linear-gradient(180deg, rgba(201, 162, 39, 0.05), transparent 45%),
    var(--base-800);
  border-top: 1px solid var(--brand-500);
  border-bottom: 1px solid var(--brand-500);
}

.page-about .ab-compare {
  display: grid;
  gap: 1px;
  background: var(--line-600);
  border: 1px solid var(--line-600);
  margin-top: 32px;
}

.page-about .ab-compare-col {
  background: var(--base-900);
  padding: 24px 20px 26px;
}

.page-about .ab-compare-col h3 {
  margin: 0 0 16px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--text-400);
}

.page-about .ab-compare-col ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .ab-compare-col li {
  position: relative;
  padding-left: 18px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-400);
}

.page-about .ab-compare-col li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 8px;
  height: 1px;
  background: var(--text-400);
}

.page-about .ab-compare-col--old {
  opacity: 0.58;
}

.page-about .ab-compare-col--new {
  background: linear-gradient(180deg, rgba(201, 162, 39, 0.1), rgba(201, 162, 39, 0.02));
  box-shadow: inset 3px 0 0 var(--brand-500);
}

.page-about .ab-compare-col--new h3 {
  color: var(--brand-300);
}

.page-about .ab-compare-col--new li {
  color: var(--text-100);
}

.page-about .ab-compare-col--new li::before {
  background: var(--brand-500);
  width: 10px;
}

.page-about .ab-band-note {
  margin: 22px 0 0;
  max-width: 62ch;
  font-size: 14px;
  line-height: 1.9;
  color: var(--text-400);
  border-left: 2px solid var(--brand-500);
  padding-left: 16px;
}

/* ---------- 04 内容体系 ---------- */

.page-about .ab-columns-figure {
  margin: 28px 0 0;
  border: 1px solid var(--line-600);
  overflow: hidden;
}

.page-about .ab-columns-figure img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ab-quad {
  display: grid;
  gap: 1px;
  background: var(--line-600);
  border: 1px solid var(--line-600);
  margin-top: 1px;
}

.page-about .ab-quad-cell {
  background: var(--base-900);
  padding: 22px 18px 24px;
  transition: background var(--dur-cut) var(--ease-cut), box-shadow var(--dur-cut) var(--ease-cut);
}

.page-about .ab-quad-cell:hover {
  background: var(--base-800);
  box-shadow: inset 2px 0 0 var(--brand-500);
}

.page-about .ab-quad-idx {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--brand-500);
}

.page-about .ab-quad-cell h3 {
  margin: 10px 0 0;
  font-size: 17px;
  font-weight: 700;
  color: var(--text-100);
}

.page-about .ab-quad-cell p {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--text-400);
}

/* ---------- 05 覆盖与协作 ---------- */

.page-about .ab-reach-grid {
  display: grid;
  gap: 1px;
  background: var(--line-600);
  border: 1px solid var(--line-600);
  margin-top: 28px;
}

.page-about .ab-reach {
  background: var(--base-900);
  padding: 20px 16px 22px;
}

.page-about .ab-reach-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 44px;
  font-weight: 700;
  line-height: 1;
  color: var(--brand-500);
}

.page-about .ab-reach-label {
  display: block;
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.1em;
  line-height: 1.7;
  color: var(--text-400);
}

.page-about .ab-sub-h {
  margin: 36px 0 0;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--brand-300);
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line-600);
}

.page-about .ab-persona {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .ab-persona li {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px dashed var(--line-600);
}

.page-about .ab-persona strong {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-100);
}

.page-about .ab-persona span {
  font-size: 14px;
  line-height: 1.85;
  color: var(--text-400);
}

/* ---------- 章节索引收束 ---------- */

.page-about .ab-index {
  background:
    repeating-linear-gradient(90deg, transparent 0 63px, rgba(201, 162, 39, 0.07) 63px 64px),
    var(--base-800);
}

.page-about .ab-index-grid {
  display: grid;
  gap: 8px 32px;
  margin-top: 24px;
}

.page-about .ab-index-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-index-list a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line-600);
  font-size: 14px;
  color: var(--text-400);
  text-decoration: none;
  transition: color var(--dur-cut) var(--ease-cut);
}

.page-about .ab-index-list a:hover,
.page-about .ab-index-list a:focus-visible {
  color: var(--brand-300);
}

.page-about .ab-index-list .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--brand-500);
}

.page-about .ab-cta {
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--brand-500);
}

.page-about .ab-cta-text {
  margin: 0;
  max-width: 46ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-100);
}

.page-about .ab-cta-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 20px;
  margin-top: 20px;
}

.page-about .ab-cta-link {
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--text-400);
  text-decoration: none;
  border-bottom: 1px solid var(--line-600);
  padding-bottom: 2px;
  transition: color var(--dur-cut) var(--ease-cut), border-color var(--dur-cut) var(--ease-cut);
}

.page-about .ab-cta-link:hover,
.page-about .ab-cta-link:focus-visible {
  color: var(--brand-300);
  border-color: var(--brand-300);
}

/* ---------- 断点 ---------- */

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

  .page-about .ab-work-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .ab-quad {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .ab-index-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .ab-compare {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero {
    padding-block: 64px 88px;
  }

  .page-about .ab-hero-grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: stretch;
    gap: 56px;
  }

  .page-about .ab-hero-visual {
    min-height: 100%;
  }

  .page-about .ab-hero-visual-axis {
    height: 200px;
  }

  .page-about .ab-section {
    padding-block: 88px;
  }

  .page-about .ab-chapter {
    grid-template-columns: 150px minmax(0, 1fr);
    gap: 44px;
    align-items: start;
  }

  .page-about .ab-chapter-index span {
    font-size: 120px;
  }

  .page-about .ab-tl {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 48px;
    margin-top: 48px;
  }

  .page-about .ab-tl-item {
    padding-block: 30px 26px;
  }

  .page-about .ab-team {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.82fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .ab-ring {
    width: 196px;
    height: 196px;
  }

  .page-about .ab-reach-grid {
    margin-top: 36px;
  }

  .page-about .ab-index-grid {
    gap: 8px 56px;
  }
}

@media (min-width: 1180px) {
  .page-about .ab-tl {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    column-gap: 32px;
  }

  .page-about .ab-tl-item {
    padding-right: 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-chapter-index span,
  .page-about .ab-tl-name,
  .page-about .ab-work,
  .page-about .ab-quad-cell,
  .page-about .ab-index-list a,
  .page-about .ab-cta-link {
    transition: none;
  }
}
<<<END>>>