.page-about {
  --ab-gap: clamp(56px, 8vw, 104px);
  --ab-soft: rgba(36, 55, 77, 0.6);
}

/* ---------- 面包屑 ---------- */
.page-about .ab-crumb {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--muted);
  margin-bottom: clamp(26px, 4vw, 50px);
}
.page-about .ab-crumb a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}
.page-about .ab-crumb a:hover {
  color: var(--orange);
  border-bottom-color: var(--orange);
}
.page-about .ab-crumb [aria-current="page"] {
  color: var(--cream);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  padding-top: calc(var(--header-h) + 40px);
  padding-bottom: clamp(30px, 5vw, 56px);
}
.page-about .ab-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
}
@media (min-width: 980px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 1fr);
    gap: clamp(40px, 6vw, 88px);
    align-items: end;
  }
}
.page-about h1 {
  margin: 16px 0 24px;
  font-family: var(--sans);
  font-size: clamp(30px, 5.4vw, 58px);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.12;
  color: var(--cream);
  max-width: 21ch;
}
.page-about .ab-lede {
  margin: 0;
  font-size: 17px;
  line-height: 1.78;
  color: var(--text);
  max-width: 60ch;
}

.page-about .ab-hero__figures {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  clip-path: var(--cut-lg);
  align-self: end;
}
.page-about .ab-figure {
  background: var(--bg-panel);
  padding: 20px 14px 18px;
}
.page-about .ab-figure__n {
  display: block;
  font-family: var(--mono);
  font-size: clamp(26px, 3.4vw, 40px);
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -0.03em;
}
.page-about .ab-figure__c {
  display: block;
  margin-top: 11px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--muted);
  letter-spacing: 0.05em;
}

/* ---------- 章节索引条 ---------- */
.page-about .ab-index {
  position: sticky;
  top: var(--header-h);
  z-index: 15;
  background: rgba(10, 26, 47, 0.95);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.page-about .ab-index ul {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0 0 0 clamp(16px, 4vw, 40px);
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}
.page-about .ab-index ul::-webkit-scrollbar {
  display: none;
}
.page-about .ab-index li {
  flex: 0 0 auto;
}
.page-about .ab-index a {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 15px 18px;
  font-size: 14px;
  white-space: nowrap;
  color: var(--muted);
  text-decoration: none;
  border-right: 1px solid var(--line);
  transition: color 0.18s ease, background-color 0.18s ease;
}
.page-about .ab-index a .mono-label {
  color: var(--gold);
}
.page-about .ab-index a:hover,
.page-about .ab-index a:focus-visible {
  color: var(--cream);
  background: var(--bg-panel);
}
.page-about .ab-index a:focus-visible {
  outline: none;
  box-shadow: inset 0 -2px 0 var(--orange);
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-sec {
  padding-block: var(--ab-gap);
}
.page-about .ab-sec + .ab-sec {
  border-top: 1px solid var(--line);
}
.page-about .ab-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
}
@media (min-width: 1000px) {
  .page-about .ab-grid {
    grid-template-columns: 124px minmax(0, 1fr);
    gap: 0 clamp(32px, 4vw, 56px);
  }
  .page-about .ab-grid--side {
    grid-template-columns: 124px minmax(0, 1fr) 248px;
    gap: 0 clamp(28px, 3.4vw, 48px);
  }
  .page-about .ab-idx {
    position: sticky;
    top: calc(var(--header-h) + 86px);
    align-self: start;
  }
}

.page-about .ab-idx {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}
@media (min-width: 1000px) {
  .page-about .ab-idx {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    border-bottom: 0;
    border-left: 2px solid var(--line);
    padding: 2px 0 2px 14px;
  }
}
.page-about .ab-idx .mono-label {
  color: var(--gold);
}
.page-about .ab-idx__name {
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .ab-h2 {
  margin: 0 0 20px;
  font-family: var(--sans);
  font-size: clamp(23px, 3.1vw, 38px);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.18;
  color: var(--cream);
  max-width: 24ch;
}
.page-about .ab-p {
  margin: 0 0 18px;
  font-size: 17px;
  line-height: 1.78;
  color: var(--text);
  max-width: 64ch;
}
.page-about .ab-p:last-child {
  margin-bottom: 0;
}

.page-about .ab-side {
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--muted);
}
.page-about .ab-side .mono-label {
  display: block;
  margin-bottom: 10px;
  color: var(--gold);
}
.page-about .ab-side p:last-child {
  margin-bottom: 0;
}
@media (min-width: 1000px) {
  .page-about .ab-side {
    padding-left: 18px;
    border-left: 2px solid var(--line);
  }
}

/* ---------- 图片容器 ---------- */
.page-about .ab-fig {
  margin: 28px 0 0;
  border: 1px solid var(--line);
  background: var(--bg-panel);
  clip-path: var(--cut-lg);
  overflow: hidden;
}
.page-about .ab-fig img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}
.page-about .ab-fig__cap {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--muted);
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  background: var(--bg-deep);
}

/* ---------- 大号数字条 ---------- */
.page-about .ab-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  margin: 28px 0 0;
}
.page-about .ab-stat {
  background: var(--bg-panel);
  padding: 22px 18px;
}
.page-about .ab-stat__n {
  display: block;
  font-family: var(--mono);
  font-size: clamp(34px, 4.6vw, 56px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--cyan);
}
.page-about .ab-stat__u {
  display: block;
  margin-top: 12px;
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--muted);
}

/* ---------- 资产：乳白索引卡 ---------- */
.page-about .ab-asset {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  margin: 28px 0 0;
}
@media (min-width: 760px) {
  .page-about .ab-asset {
    grid-template-columns: 1fr 1fr;
  }
}
.page-about .ab-asset__card {
  background: var(--cream);
  color: var(--ink);
  padding: 26px 24px 28px;
  clip-path: var(--cut-lg);
}
.page-about .ab-asset__card .mono-label {
  color: var(--ink);
  opacity: 0.6;
}
.page-about .ab-asset__card h3 {
  margin: 10px 0 12px;
  font-size: clamp(19px, 2.4vw, 25px);
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.page-about .ab-asset__card p {
  margin: 0 0 18px;
  font-size: 15.5px;
  line-height: 1.72;
  color: rgba(27, 22, 17, 0.78);
  max-width: 44ch;
}
.page-about .ab-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.page-about .ab-chips li {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  padding: 5px 11px;
  border: 1px solid rgba(27, 22, 17, 0.32);
  color: var(--ink);
}

.page-about .ab-model {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 16px;
  margin-top: 22px;
  padding: 24px clamp(18px, 3vw, 30px);
  background: var(--bg-panel);
  border-left: 3px solid var(--cyan);
}
@media (min-width: 620px) {
  .page-about .ab-model {
    flex-direction: row;
    align-items: center;
    gap: clamp(18px, 3vw, 32px);
  }
}
.page-about .ab-model__n {
  flex: 0 0 auto;
  font-family: var(--mono);
  font-size: clamp(36px, 5vw, 60px);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--cyan);
}
.page-about .ab-model__txt strong {
  display: block;
  margin-bottom: 6px;
  font-size: 15px;
  color: var(--cream);
}
.page-about .ab-model__txt p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--muted);
  max-width: 54ch;
}

/* ---------- 七区域分区图 ---------- */
.page-about .ab-regions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  list-style: none;
  margin: 32px 0 0;
  padding: 0;
}
@media (min-width: 720px) {
  .page-about .ab-regions {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}
@media (min-width: 1120px) {
  .page-about .ab-regions {
    grid-template-columns: repeat(7, minmax(0, 1fr));
  }
}
.page-about .ab-region {
  background: var(--bg-deep);
  padding: 20px 14px 18px;
  transition: background-color 0.18s ease;
}
.page-about .ab-region:hover {
  background: var(--bg-panel);
}
.page-about .ab-region__name {
  display: block;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--cream);
}
.page-about .ab-region__txt {
  display: block;
  margin-top: 9px;
  font-size: 12.5px;
  line-height: 1.62;
  color: var(--muted);
}

/* ---------- 校准三步 ---------- */
.page-about .ab-steps {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}
@media (min-width: 760px) {
  .page-about .ab-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}
.page-about .ab-step {
  background: var(--bg-panel);
  padding: 24px 20px 26px;
}
.page-about .ab-step .mono-label {
  display: block;
  margin-bottom: 14px;
  color: var(--gold);
}
.page-about .ab-step h3 {
  margin: 0 0 12px;
  font-size: 18px;
  font-weight: 700;
  color: var(--cream);
}
.page-about .ab-step p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--muted);
}

/* ---------- 九道工序 ---------- */
.page-about .ab-ops {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  list-style: none;
  margin: 28px 0;
  padding: 0;
}
@media (min-width: 820px) {
  .page-about .ab-ops {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}
.page-about .ab-ops li {
  display: flex;
  align-items: baseline;
  gap: 12px;
  background: var(--bg-deep);
  padding: 16px 16px 18px;
  transition: background-color 0.18s ease;
}
.page-about .ab-ops li:hover {
  background: var(--bg-panel);
}
.page-about .ab-ops__n {
  flex: 0 0 auto;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--gold);
}
.page-about .ab-ops__t {
  font-size: 14.5px;
  color: var(--text);
}

/* ---------- 墨色事实区 ---------- */
.page-about .ab-facts {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: rgba(242, 239, 230, 0.14);
  border: 1px solid rgba(242, 239, 230, 0.14);
  margin-top: 28px;
}
@media (min-width: 700px) {
  .page-about .ab-facts {
    grid-template-columns: 1fr 1fr;
  }
}
.page-about .ab-fact {
  background: var(--ink);
  padding: 24px 22px;
}
.page-about .ab-fact .mono-label {
  color: var(--gold);
}
.page-about .ab-fact__v {
  margin: 10px 0 0;
  font-family: var(--mono);
  font-size: 17px;
  letter-spacing: 0.02em;
  color: var(--cream);
}
.page-about .ab-fact__d {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.68;
  color: rgba(242, 239, 230, 0.62);
}

/* ---------- 版本演进带 ---------- */
.page-about .ab-track {
  display: grid;
  grid-template-columns: 1fr;
  list-style: none;
  margin: clamp(30px, 4vw, 46px) 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}
@media (min-width: 820px) {
  .page-about .ab-track {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}
.page-about .ab-node {
  position: relative;
  padding: 26px 0 22px;
  border-bottom: 1px solid var(--line);
}
.page-about .ab-node::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 40px;
  height: 2px;
  background: var(--line);
}
.page-about .ab-node--now::before {
  background: var(--orange);
}
@media (min-width: 820px) {
  .page-about .ab-node {
    padding: 28px clamp(20px, 3vw, 34px) 20px 0;
    border-bottom: 0;
    border-right: 1px solid var(--line);
  }
  .page-about .ab-node:last-child {
    border-right: 0;
    padding-right: 0;
  }
}
.page-about .ab-node__ver {
  display: inline-block;
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--gold);
  padding: 4px 10px;
  border: 1px solid var(--line);
}
.page-about .ab-node--now .ab-node__ver {
  color: var(--orange);
  border-color: var(--orange);
}
.page-about .ab-node h3 {
  margin: 16px 0 10px;
  font-size: 19px;
  font-weight: 700;
  color: var(--cream);
}
.page-about .ab-node p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--muted);
  max-width: 42ch;
}

/* ---------- 收束 ---------- */
.page-about .ab-next {
  padding-block: clamp(56px, 8vw, 100px);
  border-top: 1px solid var(--line);
}
.page-about .ab-next__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}
@media (min-width: 820px) {
  .page-about .ab-next__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: end;
    gap: 48px;
  }
}
.page-about .ab-next__act {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}
.page-about .ab-next__links {
  display: flex;
  flex-wrap: wrap;
  gap: 26px;
  margin-top: 30px;
}
.page-about .ab-next__links a {
  font-family: var(--mono);
  font-size: 12.5px;
  letter-spacing: 0.12em;
  color: var(--muted);
  text-decoration: none;
  padding-bottom: 3px;
  border-bottom: 1px solid var(--line);
  transition: color 0.18s ease, border-color 0.18s ease;
}
.page-about .ab-next__links a:hover,
.page-about .ab-next__links a:focus-visible {
  color: var(--cream);
  border-bottom-color: var(--orange);
}

/* ---------- 动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition: none !important;
    animation: none !important;
  }
}