.page-about {
  --ab-rail: 30px;
  --ab-pad: 20px;
  position: relative;
}

/* ---------- 面包屑 ---------- */
.page-about .ab-crumbs {
  padding-top: 24px;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding-top: 32px;
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  right: -14%;
  top: -34%;
  width: 68%;
  height: 178%;
  background: linear-gradient(158deg, rgba(217, 30, 46, .30), rgba(122, 18, 38, .10) 58%, transparent 82%);
  clip-path: polygon(32% 0, 100% 0, 68% 100%, 0 100%);
  pointer-events: none;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: var(--line);
  pointer-events: none;
}

.page-about .ab-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .ab-hero__title {
  margin: 14px 0 0;
  font-size: clamp(56px, 15vw, 128px);
  line-height: .88;
  font-weight: 900;
  letter-spacing: -.02em;
  color: var(--mist);
  text-shadow: 0 24px 60px rgba(0, 0, 0, .55);
}

.page-about .ab-hero__lead {
  max-width: 34em;
  margin: 20px 0 0;
  color: var(--ink-dim);
}

.page-about .ab-facts {
  list-style: none;
  margin: 34px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-facts__item {
  background: var(--night);
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}

.page-about .ab-facts__k {
  font-size: 12px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.page-about .ab-facts__v {
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 700;
  color: var(--mist);
  word-break: break-word;
}

/* ---------- 通用小节标题 ---------- */
.page-about .ab-sec-title {
  margin: 10px 0 0;
  font-size: clamp(28px, 6vw, 52px);
  line-height: 1.02;
  font-weight: 900;
  letter-spacing: -.02em;
}

.page-about .ab-sec-title--dark {
  color: var(--dark-text);
}

/* ---------- 起点 ---------- */
.page-about .ab-origin__grid {
  display: grid;
  gap: 28px;
}

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

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

.page-about .ab-origin__body .csg-text {
  margin-top: 16px;
}

.page-about .ab-origin__body .csg-note {
  margin-top: 20px;
}

/* ---------- 版本时间线 ---------- */
.page-about .ab-tl {
  position: relative;
  overflow: hidden;
}

.page-about .ab-tl__glow {
  position: absolute;
  inset: 0;
  opacity: .18;
  pointer-events: none;
}

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

.page-about .ab-tl__inner {
  position: relative;
  z-index: 1;
}

.page-about .ab-tl__lead {
  max-width: 32em;
  margin-top: 16px;
  color: var(--ink-dim);
}

.page-about .ab-track {
  list-style: none;
  margin: 40px 0 0;
  padding: 0 0 0 var(--ab-rail);
  position: relative;
}

.page-about .ab-track::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 8px;
  width: 22px;
  background: linear-gradient(180deg, rgba(217, 30, 46, .48), rgba(122, 18, 38, .22) 56%, rgba(76, 107, 138, .10));
  clip-path: polygon(30% 0, 100% 0, 70% 100%, 0 100%);
}

.page-about .ab-node {
  position: relative;
  padding-bottom: 26px;
  outline: none;
}

.page-about .ab-node:last-child {
  padding-bottom: 0;
}

.page-about .ab-node__ring {
  position: absolute;
  left: calc(-1 * var(--ab-rail) + 5px);
  top: 16px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 1px solid var(--line-strong);
  background: var(--graphite);
  transition: background-color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .ab-node--current .ab-node__ring {
  background: var(--red);
  border-color: var(--red);
  box-shadow: 0 0 0 5px rgba(217, 30, 46, .18);
}

.page-about .ab-node__card {
  border: 1px solid var(--line);
  background: rgba(19, 26, 36, .74);
  border-radius: var(--radius);
  padding: 18px 18px 20px;
  transition: border-color .2s var(--ease);
}

.page-about .ab-node:hover .ab-node__card,
.page-about .ab-node:focus-visible .ab-node__card {
  border-color: var(--line-strong);
}

.page-about .ab-node__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
}

.page-about .ab-node__gen {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--red);
  text-transform: uppercase;
}

.page-about .ab-badge {
  font-size: 11px;
  letter-spacing: .1em;
}

.page-about .ab-node__era {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--ink-faint);
}

.page-about .ab-node__title {
  margin: 10px 0 0;
  font-size: clamp(20px, 4.4vw, 26px);
  font-weight: 800;
  line-height: 1.18;
  color: var(--mist);
  letter-spacing: -.01em;
}

.page-about .ab-node__card .csg-text {
  margin-top: 12px;
  color: var(--ink-dim);
  font-size: 15.5px;
}

.page-about .ab-node__fix {
  margin: 14px 0 0;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.7;
  color: var(--cyan);
}

/* ---------- 浅色区（口径修订） ---------- */
.page-about .ab-light {
  background: var(--mist);
  color: var(--dark-text);
}

.page-about .ab-light .csg-label {
  color: var(--dark-text-dim);
}

.page-about .ab-light .csg-text {
  color: var(--dark-text-dim);
}

.page-about .ab-rev-sec__intro {
  max-width: 34em;
  margin-top: 16px;
}

.page-about .ab-desk {
  margin: 32px 0 0;
}

.page-about .ab-desk .csg-media__caption {
  color: var(--dark-text-dim);
}

.page-about .ab-revs {
  margin-top: 32px;
  border-top: 1px solid var(--line-dark);
}

.page-about .ab-rev {
  border-bottom: 1px solid var(--line-dark);
  background: #FFFFFF;
}

.page-about .ab-rev:nth-child(even) {
  background: var(--stripe-gray);
}

.page-about .ab-rev[open] {
  background: #FFFFFF;
}

.page-about .ab-rev__sum {
  list-style: none;
  cursor: pointer;
  display: grid;
  grid-template-columns: auto 1fr auto auto;
  gap: 10px 12px;
  align-items: center;
  padding: 15px 14px;
}

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

.page-about .ab-rev__sum::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--red);
  line-height: 1;
}

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

.page-about .ab-rev__ver {
  font-family: var(--font-mono);
  font-size: 17px;
  font-weight: 700;
  color: var(--red);
  letter-spacing: .04em;
}

.page-about .ab-rev__name {
  font-size: 15px;
  font-weight: 600;
  color: var(--dark-text);
  min-width: 0;
}

.page-about .ab-rev__when {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--dark-text-dim);
  white-space: nowrap;
}

.page-about .ab-rev__body {
  padding: 0 14px 18px;
}

.page-about .ab-rev__body .csg-kv {
  color: var(--dark-text);
}

.page-about .ab-rev__body .csg-kv + .csg-kv {
  margin-top: 10px;
}

.page-about .ab-rev__body .csg-kv__k {
  color: var(--dark-text-dim);
}

.page-about .ab-rev__body .csg-kv__v {
  color: var(--dark-text);
}

/* ---------- 编辑部 ---------- */
.page-about .ab-team-sec__intro {
  max-width: 36em;
  margin-top: 16px;
  color: var(--ink-dim);
}

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

.page-about .ab-team__row {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 15px 16px;
  display: grid;
  gap: 4px 14px;
  grid-template-columns: auto 1fr;
  align-items: baseline;
}

.page-about .ab-team__row::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: var(--w, 50%);
  background: linear-gradient(90deg, rgba(217, 30, 46, .30), rgba(217, 30, 46, .04));
  clip-path: polygon(0 0, 100% 0, calc(100% - 22px) 100%, 0 100%);
  pointer-events: none;
}

.page-about .ab-team__row--a { --w: 100%; }
.page-about .ab-team__row--b { --w: 72%; }
.page-about .ab-team__row--c { --w: 54%; }
.page-about .ab-team__row--d { --w: 22%; }

.page-about .ab-team__n {
  position: relative;
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--mist);
  letter-spacing: -.02em;
}

.page-about .ab-team__role {
  position: relative;
  font-size: 15px;
  font-weight: 700;
  color: var(--mist);
}

.page-about .ab-team__desc {
  position: relative;
  grid-column: 2;
  font-size: 13px;
  line-height: 1.7;
  color: var(--ink-dim);
}

.page-about .ab-team__cadence {
  margin-top: 36px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.page-about .ab-cadence {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
}

.page-about .ab-cadence__item {
  display: grid;
  gap: 6px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-cadence__item:last-child {
  border-bottom: none;
}

.page-about .ab-cadence__k {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--cyan);
}

.page-about .ab-cadence__v {
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-dim);
}

/* ---------- 内容分类 ---------- */
.page-about .ab-cats-sec__intro {
  max-width: 36em;
  margin-top: 16px;
  color: var(--ink-dim);
}

.page-about .ab-cats {
  list-style: none;
  margin: 32px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .ab-cats__item {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 14px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-cats__num {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  color: var(--red);
  line-height: 1.2;
}

.page-about .ab-cats__name {
  margin: 0;
  font-size: 19px;
  font-weight: 800;
  color: var(--mist);
  letter-spacing: -.01em;
}

.page-about .ab-cats__name em {
  font-style: normal;
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--steel);
  margin-left: 8px;
  vertical-align: 2px;
}

.page-about .ab-cats__body .csg-text {
  margin-top: 8px;
  font-size: 15px;
  color: var(--ink-dim);
}

.page-about .ab-cats__note {
  margin-top: 26px;
}

/* ---------- 季度说明 ---------- */
.page-about .ab-quarter__grid {
  display: grid;
  gap: 26px;
}

.page-about .ab-quarter__mark {
  margin: 14px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(30px, 8vw, 56px);
  font-weight: 700;
  line-height: .98;
  letter-spacing: -.02em;
  color: transparent;
  -webkit-text-stroke: 1px var(--red);
  text-stroke: 1px var(--red);
}

.page-about .ab-quarter__body .csg-text {
  margin-top: 16px;
  color: var(--ink-dim);
}

.page-about .ab-quarter__body .csg-note {
  margin-top: 20px;
}

.page-about .ab-quarter__link {
  margin: 24px 0 0;
}

/* ---------- 边界清单 ---------- */
.page-about .ab-not__list {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-not__item {
  display: grid;
  grid-template-columns: 28px 1fr;
  gap: 12px;
  align-items: start;
  background: var(--graphite);
  padding: 16px;
}

.page-about .ab-not__mark {
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.6;
  color: var(--red);
}

.page-about .ab-not__text {
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--ink-dim);
}

.page-about .ab-not__tail {
  margin: 22px 0 0;
  font-size: 13.5px;
  line-height: 1.8;
  color: var(--ink-faint);
}

.page-about .ab-not__tail a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(35, 224, 200, .35);
}

.page-about .ab-not__tail a:hover {
  border-bottom-color: var(--cyan);
}

/* ---------- 延伸入口 ---------- */
.page-about .ab-more {
  padding-bottom: 40px;
}

.page-about .ab-more__links {
  margin-top: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 时间戳带 ---------- */
.page-about .ab-stamp {
  margin-bottom: 8px;
}

/* ---------- 小屏细节 ---------- */
.page-about .ab-node__card {
  word-break: break-word;
}

.page-about .ab-rev__name,
.page-about .ab-team__desc,
.page-about .ab-cadence__v {
  overflow-wrap: anywhere;
}

/* ---------- 断点：≥560px ---------- */
@media (min-width: 560px) {
  .page-about {
    --ab-rail: 40px;
  }

  .page-about .ab-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .ab-cats__item {
    grid-template-columns: 56px 1fr;
  }

  .page-about .ab-cadence__item {
    grid-template-columns: 168px 1fr;
    gap: 18px;
    align-items: baseline;
  }

  .page-about .ab-team__row {
    grid-template-columns: 78px 1fr;
    align-items: center;
  }

  .page-about .ab-team__desc {
    grid-column: 2;
  }
}

/* ---------- 断点：≥860px ---------- */
@media (min-width: 860px) {
  .page-about {
    --ab-rail: 56px;
  }

  .page-about .ab-crumbs {
    padding-top: 30px;
  }

  .page-about .ab-hero {
    padding-top: 48px;
    padding-bottom: 56px;
  }

  .page-about .ab-origin__grid {
    grid-template-columns: 5fr 7fr;
    gap: 48px;
    align-items: start;
  }

  .page-about .ab-quarter__grid {
    grid-template-columns: 4fr 8fr;
    gap: 56px;
    align-items: start;
  }

  .page-about .ab-track {
    margin-top: 52px;
  }

  .page-about .ab-node--2 .ab-node__card {
    margin-left: 24px;
  }

  .page-about .ab-node--3 .ab-node__card {
    margin-left: 48px;
  }

  .page-about .ab-node--4 .ab-node__card {
    margin-left: 72px;
  }

  .page-about .ab-rev__sum {
    grid-template-columns: 76px 1fr 150px auto;
    padding: 18px 20px;
  }

  .page-about .ab-rev__body {
    padding: 0 20px 22px 96px;
  }

  .page-about .ab-rev__body .csg-kv {
    display: grid;
    grid-template-columns: 132px 1fr;
    gap: 18px;
  }
}

/* ---------- 断点：≥1120px ---------- */
@media (min-width: 1120px) {
  .page-about .ab-hero__title {
    font-size: clamp(96px, 11vw, 128px);
  }

  .page-about .ab-team {
    gap: 12px;
  }

  .page-about .ab-cats__item {
    padding: 24px 0;
  }
}

/* ---------- 动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .ab-node__card,
  .page-about .ab-node__ring {
    transition: none;
  }
}
</main>