.page-about {
  --ab-rail-w: 2px;
  --ab-node: 14px;
  --ab-gap: clamp(16px, 3vw, 28px);
}

.page-about .crumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0 0 clamp(20px, 3vw, 34px);
  padding: 0;
  list-style: none;
}

.page-about .crumbs li {
  font-size: 0.85rem;
  color: var(--muted);
}

.page-about .crumbs li + li::before {
  content: "/";
  margin-right: 8px;
  opacity: 0.5;
}

.page-about .crumbs a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px dotted currentColor;
}

.page-about .crumbs a:hover,
.page-about .crumbs a:focus-visible {
  color: var(--zest);
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  padding-block: clamp(20px, 4vw, 42px) clamp(40px, 6vw, 84px);
}

.page-about .ab-hero .shell {
  position: relative;
}

.page-about .ab-hero__stage {
  display: grid;
  gap: clamp(24px, 4vw, 46px);
  align-items: center;
}

.page-about .ab-hero__title {
  margin: 10px 0 0;
  font-size: clamp(2.15rem, 6.2vw, 4.1rem);
  line-height: 1.06;
  letter-spacing: -0.01em;
}

.page-about .ab-hero__lede {
  max-width: 40ch;
  margin-top: clamp(14px, 2.4vw, 22px);
}

.page-about .ab-hero__meta {
  margin-top: clamp(16px, 2.4vw, 24px);
  font-family: var(--font-mono);
  font-size: 0.86rem;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.page-about .ab-hero__meta b {
  color: var(--zest);
  font-weight: 700;
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}

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

.page-about .ab-index {
  display: none;
}

@media (min-width: 900px) {
  .page-about .ab-hero__stage {
    grid-template-columns: minmax(0, 1.04fr) minmax(0, 0.96fr);
    gap: clamp(28px, 4vw, 58px);
  }

  .page-about .ab-hero__fig {
    transform: rotate(-1.4deg);
  }
}

@media (min-width: 1200px) {
  .page-about .ab-index {
    display: flex;
    position: absolute;
    right: -6px;
    top: clamp(40px, 6vw, 86px);
    writing-mode: vertical-rl;
    gap: 16px;
    padding-left: 8px;
    border-left: 1px solid var(--line);
  }

  .page-about .ab-index a {
    font-size: 0.76rem;
    letter-spacing: 0.18em;
    color: var(--muted);
    text-decoration: none;
    transition: color 0.25s var(--ease);
  }

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

/* ---------- 章节公共头部 ---------- */

.page-about .ab-head {
  align-self: start;
}

.page-about .ab-head__note {
  margin-top: 12px;
  max-width: 22ch;
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .ab-lede {
  max-width: 36ch;
  font-size: 1.06rem;
  line-height: 1.85;
}

.page-about .ab-story .ab-lede,
.page-about .ab-cycle .ab-lede,
.page-about .ab-version .ab-lede {
  max-width: 44ch;
}

/* ---------- 时间线 ---------- */

.page-about .ab-tl {
  display: grid;
  gap: clamp(18px, 3vw, 30px);
  margin-top: clamp(26px, 4vw, 42px);
}

.page-about .ab-tl__rail {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-left: 30px;
}

.page-about .ab-tl__rail::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 12px;
  bottom: 12px;
  width: var(--ab-rail-w);
  background: linear-gradient(180deg, var(--zest), var(--flood) 42%, var(--line) 82%, transparent);
  opacity: 0.85;
}

.page-about .ab-tl__node {
  position: relative;
  display: grid;
  gap: 3px;
  width: 100%;
  padding: 10px 8px 10px 0;
  border: 0;
  background: none;
  text-align: left;
  font: inherit;
  color: var(--muted);
  cursor: pointer;
  transition: color 0.25s var(--ease);
}

.page-about .ab-tl__node::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 15px;
  box-sizing: border-box;
  width: var(--ab-node);
  height: var(--ab-node);
  border-radius: 50%;
  background: var(--ink-850);
  border: 2px solid var(--line);
  transition: background 0.25s var(--ease), border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.page-about .ab-tl__node:hover,
.page-about .ab-tl__node:focus-visible {
  color: var(--mist);
}

.page-about .ab-tl__node[aria-selected="true"] {
  color: var(--zest);
}

.page-about .ab-tl__node[aria-selected="true"]::before {
  background: var(--zest);
  border-color: var(--zest);
  box-shadow: 0 0 0 4px rgba(232, 255, 82, 0.18);
}

.page-about .ab-tl__year {
  font-size: 1.18rem;
  letter-spacing: 0.04em;
}

.page-about .ab-tl__name {
  font-size: 0.88rem;
  line-height: 1.5;
}

.page-about .ab-tl__panel {
  padding: clamp(18px, 3vw, 30px);
  border: 1px solid var(--line);
  border-left: 3px solid var(--zest);
  border-radius: var(--r-md);
  background: rgba(243, 234, 214, 0.05);
  animation: ab-fade 0.42s var(--ease) both;
}

.page-about .ab-tl__panel p {
  max-width: 42ch;
  margin-top: 10px;
  line-height: 1.85;
}

.page-about .ab-tl__fact {
  font-family: var(--font-mono);
  font-size: 0.84rem;
  letter-spacing: 0.03em;
  color: var(--flood);
}

.page-about .ab-tl__fact .num {
  color: var(--zest);
}

@keyframes ab-fade {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: none; }
}

@media (min-width: 880px) {
  .page-about .ab-tl {
    grid-template-columns: minmax(190px, 216px) minmax(0, 1fr);
    align-items: start;
  }
}

/* ---------- 团队 ---------- */

.page-about .ab-roles {
  display: grid;
  gap: clamp(14px, 2.4vw, 22px);
  margin-top: clamp(26px, 4vw, 44px);
}

.page-about .ab-role {
  padding: clamp(18px, 2.8vw, 28px);
  border: 1px solid rgba(23, 33, 31, 0.16);
  border-radius: var(--r-md);
  background: rgba(255, 255, 255, 0.45);
}

.page-about .ab-role--lead {
  background: var(--paper);
  border-color: rgba(23, 33, 31, 0.08);
  box-shadow: 0 18px 42px rgba(23, 33, 31, 0.14);
}

.page-about .ab-role__n {
  display: block;
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--ink-800);
  letter-spacing: 0.02em;
}

.page-about .ab-role--lead .ab-role__n {
  color: var(--ember);
}

.page-about .ab-role p {
  margin-top: 10px;
  line-height: 1.82;
  color: rgba(23, 33, 31, 0.78);
}

@media (min-width: 760px) {
  .page-about .ab-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .ab-role--lead {
    transform: translateY(-10px);
  }
}

/* ---------- 90 分钟流程 ---------- */

.page-about .ab-flow {
  display: grid;
  gap: clamp(22px, 3.4vw, 40px);
  margin-top: clamp(20px, 3vw, 34px);
}

.page-about .ab-flow__list {
  display: grid;
  gap: clamp(14px, 2.2vw, 20px);
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-flow .path__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: clamp(12px, 2vw, 20px);
  padding: clamp(16px, 2.6vw, 24px);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: linear-gradient(135deg, rgba(127, 216, 198, 0.07), rgba(16, 50, 44, 0.6));
}

.page-about .ab-flow .path__num {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--flood);
  letter-spacing: 0.04em;
}

.page-about .ab-flow .path__item:last-child {
  border-color: rgba(232, 255, 82, 0.42);
}

.page-about .ab-flow .path__item:last-child .path__num {
  color: var(--zest);
}

.page-about .ab-flow .path__body p {
  margin-top: 8px;
  max-width: 44ch;
  line-height: 1.82;
  color: var(--muted);
}

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

@media (min-width: 900px) {
  .page-about .ab-flow {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: start;
  }

  .page-about .ab-flow__fig {
    position: sticky;
    top: calc(var(--nav-h) + 24px);
  }
}

/* ---------- 数据来源 ---------- */

.page-about .ab-facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: clamp(14px, 2.4vw, 24px);
  margin: clamp(22px, 3.4vw, 34px) 0 0;
  padding: 0;
}

.page-about .ab-facts > div {
  padding-top: 12px;
  border-top: 2px solid var(--ember);
}

.page-about .ab-facts dt {
  font-family: var(--font-mono);
  font-size: 1.7rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--ink-800);
}

.page-about .ab-unit {
  margin-left: 2px;
  font-size: 0.82rem;
  letter-spacing: 0.04em;
}

.page-about .ab-facts dd {
  margin: 6px 0 0;
  font-size: 0.92rem;
  line-height: 1.7;
  color: rgba(23, 33, 31, 0.72);
}

.page-about .ab-quote {
  margin: clamp(24px, 3.6vw, 38px) 0 0;
  padding: clamp(18px, 2.8vw, 28px) clamp(20px, 3vw, 32px);
  background: var(--paper-2);
  border-left: 4px solid var(--ember);
  border-radius: 0 var(--r-md) var(--r-md) 0;
  font-size: 1.02rem;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .ab-sources__side {
  align-self: start;
  padding-top: 6px;
}

.page-about .ab-sources__side .annot {
  color: rgba(23, 33, 31, 0.55);
}

/* ---------- 版本 ---------- */

.page-about .ab-vers {
  display: grid;
  gap: clamp(16px, 2.6vw, 24px);
  margin-top: clamp(24px, 3.6vw, 40px);
}

.page-about .ab-vers__card {
  padding: clamp(20px, 3vw, 30px);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: radial-gradient(120% 120% at 0% 0%, rgba(232, 255, 82, 0.09), rgba(10, 26, 42, 0.5) 62%);
}

.page-about .ab-vers__card:nth-child(2) {
  background: radial-gradient(120% 120% at 100% 0%, rgba(255, 138, 61, 0.12), rgba(10, 26, 42, 0.5) 62%);
}

.page-about .ab-vers__card .h3 {
  margin-top: 14px;
}

.page-about .ab-vers__card p {
  margin-top: 10px;
  max-width: 44ch;
  line-height: 1.85;
  color: var(--muted);
}

@media (min-width: 780px) {
  .page-about .ab-vers {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-items: stretch;
  }
}

/* ---------- 使用场景 ---------- */

.page-about .ab-fans__grid {
  display: grid;
  gap: clamp(14px, 2.4vw, 22px);
  margin-top: clamp(24px, 3.6vw, 40px);
}

.page-about .ab-fan {
  padding: clamp(18px, 2.8vw, 28px);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: rgba(243, 234, 214, 0.045);
}

.page-about .ab-fan--lead {
  border-color: rgba(232, 255, 82, 0.48);
  background: linear-gradient(160deg, rgba(232, 255, 82, 0.1), rgba(16, 50, 44, 0.5));
}

.page-about .ab-fan__n {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  color: var(--flood);
}

.page-about .ab-fan--lead .ab-fan__n {
  color: var(--zest);
}

.page-about .ab-fan .h3 {
  margin-top: 12px;
}

.page-about .ab-fan p {
  margin-top: 10px;
  line-height: 1.82;
  color: var(--muted);
}

@media (min-width: 860px) {
  .page-about .ab-fans__grid {
    grid-template-columns: 1.18fr 1fr 1fr;
    align-items: start;
  }
}

/* ---------- 西安 ---------- */

.page-about .ab-tax {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .ab-tax .tag {
  white-space: nowrap;
}

.page-about .ab-tax__note {
  margin-top: 16px;
  max-width: 46ch;
  line-height: 1.82;
  color: var(--muted);
}

.page-about .ab-night {
  margin: clamp(28px, 4.4vw, 52px) auto 0;
  width: min(100% - 2 * var(--gutter), var(--shell-w));
}

.page-about .ab-night img {
  border-radius: var(--r-lg);
}

/* ---------- 收尾 ---------- */

.page-about .ab-cta__inner {
  padding: clamp(26px, 4.2vw, 52px);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: linear-gradient(118deg, rgba(232, 255, 82, 0.12), rgba(127, 216, 198, 0.08) 58%, rgba(255, 138, 61, 0.08));
}

.page-about .ab-cta__inner .h2 {
  margin-top: 10px;
}

.page-about .ab-cta__inner > p {
  max-width: 52ch;
  margin-top: 14px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .ab-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}

/* ---------- 图片与响应式兜底 ---------- */

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

@media (max-width: 560px) {
  .page-about .ab-hero__title {
    font-size: clamp(1.85rem, 8.4vw, 2.4rem);
  }

  .page-about .ab-flow .path__item {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
  }

  .page-about .ab-facts dt {
    font-size: 1.4rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-tl__panel {
    animation: none;
  }

  .page-about .ab-hero__fig,
  .page-about .ab-role--lead {
    transform: none;
  }
}