.page-about {
  background: var(--ink);
  color: var(--mist);
  padding-bottom: clamp(48px, 7vw, 88px);
}

.page-about .ab-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  padding-block: 16px 0;
}

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

.page-about .ab-body {
  min-width: 0;
  display: grid;
  gap: clamp(44px, 6vw, 84px);
}

/* ---------- 左侧章节轨道 ---------- */
@media (min-width: 961px) {
  .page-about .ab-shell {
    grid-template-columns: 188px minmax(0, 1fr);
    gap: clamp(32px, 4vw, 64px);
    padding-block: 36px 0;
  }

  .page-about .ab-rail {
    display: block;
    position: sticky;
    top: 118px;
    align-self: start;
    padding-right: 18px;
    border-right: 1px solid var(--line);
  }
}

.page-about .ab-rail__kicker {
  color: var(--sage);
  margin: 0 0 18px;
}

.page-about .ab-rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .ab-rail__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 0 9px 14px;
  border-left: 1px solid var(--line);
  color: var(--sage);
  font-size: 13.5px;
  line-height: 1.4;
  text-decoration: none;
  transition: color .2s ease, border-color .2s ease, background-color .2s ease;
}

.page-about .ab-rail__link:hover,
.page-about .ab-rail__link:focus-visible {
  color: var(--cyan);
  border-left-color: var(--cyan);
  background: rgba(53, 240, 200, .06);
  outline: none;
}

.page-about .ab-rail__num {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .12em;
  color: var(--amber);
}

.page-about .ab-rail__stamp {
  margin: 24px 0 0;
  padding-top: 14px;
  border-top: 1px dashed var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.7;
  letter-spacing: .06em;
  color: var(--sage);
}

.page-about .ab-rail__stamp span {
  color: var(--cyan);
}

/* ---------- 面包屑 ---------- */
.page-about .ab-crumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--sage);
}

.page-about .ab-crumb a {
  color: var(--sage);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s ease, border-color .2s ease;
}

.page-about .ab-crumb a:hover,
.page-about .ab-crumb a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--line-cyan);
  outline: none;
}

/* ---------- 首屏框景 ---------- */
.page-about .ab-hero {
  position: relative;
  padding: clamp(22px, 4vw, 44px);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background:
    radial-gradient(120% 95% at 92% -10%, rgba(53, 240, 200, .13), transparent 62%),
    radial-gradient(80% 70% at 0% 110%, rgba(242, 163, 58, .10), transparent 66%),
    linear-gradient(158deg, var(--field) 0%, var(--ink-deep) 100%);
  overflow: hidden;
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 13px;
  border-radius: calc(var(--r-lg) - 10px);
  border: 1px dashed rgba(147, 168, 162, .16);
  pointer-events: none;
}

.page-about .ab-hero__meta {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0 0 18px;
}

.page-about .ab-hero__code {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--sage);
}

.page-about .ab-hero__title {
  position: relative;
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(30px, 6.4vw, 58px);
  font-weight: 700;
  line-height: 1.02;
  letter-spacing: .01em;
  color: var(--mist);
}

.page-about .ab-hero__title span {
  color: var(--cyan);
}

.page-about .ab-hero__lead {
  position: relative;
  margin: 18px 0 0;
  max-width: 62ch;
  font-size: 15.5px;
  line-height: 1.85;
  color: rgba(244, 248, 246, .78);
}

.page-about .ab-stats {
  position: relative;
  list-style: none;
  margin: 26px 0 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 12px;
}

@media (min-width: 700px) {
  .page-about .ab-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .ab-stats__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(20px, 3.4vw, 28px);
  line-height: 1.1;
  color: var(--cyan);
}

.page-about .ab-stats__label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--sage);
}

/* ---------- 通用章节 ---------- */
.page-about .ab-sec {
  position: relative;
}

.page-about .ab-sec h2 {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-size: clamp(24px, 3.8vw, 38px);
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: .01em;
  color: var(--mist);
}

.page-about .ab-lead {
  margin: 14px 0 0;
  max-width: 64ch;
  font-size: 15.5px;
  line-height: 1.82;
  color: rgba(244, 248, 246, .74);
}

.page-about .ab-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  margin-top: 24px;
}

@media (min-width: 900px) {
  .page-about .ab-split {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
    gap: clamp(24px, 3.6vw, 44px);
    align-items: start;
  }

  .page-about .ab-split--flip {
    grid-template-columns: minmax(0, 1fr) minmax(0, .82fr);
  }
}

.page-about .ab-copy p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(244, 248, 246, .78);
}

.page-about .ab-copy p:last-child {
  margin-bottom: 0;
}

.page-about .ab-copy a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--line-cyan);
  transition: color .2s ease, border-color .2s ease;
}

.page-about .ab-copy a:hover,
.page-about .ab-copy a:focus-visible {
  color: var(--mist);
  border-bottom-color: var(--mist);
  outline: none;
}

/* ---------- 要点卡 ---------- */
.page-about .ab-points {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .ab-points li {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: linear-gradient(140deg, rgba(12, 59, 49, .58), rgba(4, 23, 15, .8));
}

.page-about .ab-points b {
  display: block;
  font-family: var(--font-mono);
  font-size: 19px;
  letter-spacing: .02em;
  color: var(--cyan);
}

.page-about .ab-points span {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--sage);
}

/* ---------- 四层结构 ---------- */
.page-about .ab-layers {
  position: relative;
  margin-top: 26px;
}

.page-about .ab-layers__input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.page-about .ab-layers__tabs {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

@media (min-width: 760px) {
  .page-about .ab-layers__tabs {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .ab-layers__tab {
  display: block;
  padding: 13px 14px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: rgba(4, 23, 15, .55);
  color: var(--sage);
  font-size: 13.5px;
  line-height: 1.35;
  cursor: pointer;
  transition: color .2s ease, border-color .2s ease, background-color .2s ease, box-shadow .2s ease;
}

.page-about .ab-layers__tab:hover {
  border-color: var(--line-cyan);
  color: var(--mist);
}

.page-about .ab-layers__idx {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .16em;
  color: var(--amber);
}

.page-about #ab-layer-1:checked ~ .ab-layers__tabs label[for="ab-layer-1"],
.page-about #ab-layer-2:checked ~ .ab-layers__tabs label[for="ab-layer-2"],
.page-about #ab-layer-3:checked ~ .ab-layers__tabs label[for="ab-layer-3"],
.page-about #ab-layer-4:checked ~ .ab-layers__tabs label[for="ab-layer-4"] {
  color: var(--mist);
  border-color: var(--line-cyan);
  background: rgba(53, 240, 200, .12);
  box-shadow: inset 0 0 0 1px rgba(53, 240, 200, .2);
}

.page-about #ab-layer-1:focus-visible ~ .ab-layers__tabs label[for="ab-layer-1"],
.page-about #ab-layer-2:focus-visible ~ .ab-layers__tabs label[for="ab-layer-2"],
.page-about #ab-layer-3:focus-visible ~ .ab-layers__tabs label[for="ab-layer-3"],
.page-about #ab-layer-4:focus-visible ~ .ab-layers__tabs label[for="ab-layer-4"] {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .ab-layers__panel {
  display: none;
  margin-top: 12px;
  padding: clamp(20px, 3vw, 30px);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: linear-gradient(150deg, rgba(12, 59, 49, .72), rgba(4, 23, 15, .92));
}

.page-about #ab-layer-1:checked ~ .ab-layers__panels .ab-layers__panel:nth-child(1),
.page-about #ab-layer-2:checked ~ .ab-layers__panels .ab-layers__panel:nth-child(2),
.page-about #ab-layer-3:checked ~ .ab-layers__panels .ab-layers__panel:nth-child(3),
.page-about #ab-layer-4:checked ~ .ab-layers__panels .ab-layers__panel:nth-child(4) {
  display: block;
}

.page-about .ab-layers__panel h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: clamp(19px, 2.4vw, 24px);
  font-weight: 600;
  line-height: 1.2;
  color: var(--mist);
}

.page-about .ab-layers__panel p {
  margin: 0 0 10px;
  max-width: 62ch;
  font-size: 14.5px;
  line-height: 1.82;
  color: rgba(244, 248, 246, .76);
}

.page-about .ab-layers__meta {
  margin: 0;
  font-size: 12.5px;
  letter-spacing: .04em;
  color: var(--sage);
}

.page-about .ab-layers__meta a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--line-cyan);
}

.page-about .ab-layers__meta a:hover,
.page-about .ab-layers__meta a:focus-visible {
  color: var(--mist);
  border-bottom-color: var(--mist);
  outline: none;
}

/* ---------- 版本演进 ---------- */
.page-about .ab-versions {
  overflow: hidden;
  padding: clamp(22px, 4vw, 44px);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
}

.page-about .ab-versions__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.page-about .ab-versions__bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  opacity: .3;
}

.page-about .ab-versions > *:not(.ab-versions__bg) {
  position: relative;
  z-index: 1;
}

.page-about .ab-tl {
  list-style: none;
  margin: 26px 0 0;
  padding: 0 0 0 22px;
  display: grid;
  gap: 14px;
  position: relative;
}

.page-about .ab-tl::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), rgba(53, 240, 200, .12));
}

@media (min-width: 900px) {
  .page-about .ab-tl {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
    padding-left: 22px;
  }

  .page-about .ab-tl::before {
    display: none;
  }
}

.page-about .ab-tl__item {
  position: relative;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: rgba(4, 23, 15, .68);
  transition: border-color .2s ease, background-color .2s ease;
}

.page-about .ab-tl__item::before {
  content: "";
  position: absolute;
  left: -22px;
  top: 24px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--cyan);
  box-shadow: 0 0 0 4px rgba(53, 240, 200, .12);
}

@media (min-width: 900px) {
  .page-about .ab-tl__item::before {
    left: auto;
    right: 18px;
    top: 20px;
    border-color: var(--amber);
    box-shadow: 0 0 0 4px rgba(242, 163, 58, .12);
  }
}

.page-about .ab-tl__item:hover {
  border-color: var(--line-cyan);
  background: rgba(12, 59, 49, .72);
}

.page-about .ab-tl__ver {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .14em;
  color: var(--amber);
}

.page-about .ab-tl__item h3 {
  margin: 8px 0 8px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 600;
  line-height: 1.25;
  color: var(--mist);
}

.page-about .ab-tl__item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
  color: rgba(244, 248, 246, .74);
}

/* ---------- 图文块 ---------- */
.page-about .ab-figure {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
  background: var(--ink-deep);
}

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

.page-about .ab-figure figcaption {
  padding: 10px 14px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .1em;
  color: var(--sage);
}

/* ---------- 职能分工 ---------- */
.page-about .ab-roles {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

@media (min-width: 700px) {
  .page-about .ab-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
  }
}

.page-about .ab-roles li {
  padding: 14px 0 14px 14px;
  border-left: 2px solid var(--amber);
  background: linear-gradient(90deg, rgba(242, 163, 58, .07), transparent 70%);
}

.page-about .ab-roles strong {
  display: block;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 600;
  color: var(--mist);
}

.page-about .ab-roles span {
  display: block;
  margin-top: 5px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--sage);
}

/* ---------- 联系块 ---------- */
.page-about .ab-contact {
  margin-top: 20px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: rgba(12, 59, 49, .42);
  display: grid;
  gap: 10px;
}

.page-about .ab-contact .bsp-contact__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
}

@media (min-width: 560px) {
  .page-about .ab-contact .bsp-contact__row {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 12px;
    align-items: baseline;
  }
}

.page-about .ab-contact .bsp-contact__key {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--sage);
}

.page-about .ab-contact .bsp-contact__val {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
  overflow-wrap: anywhere;
}

.page-about .ab-contact__more {
  margin: 14px 0 0;
  font-size: 13px;
}

/* ---------- 正式通道 ---------- */
.page-about .ab-verify__grid {
  margin-top: 24px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
}

@media (min-width: 760px) {
  .page-about .ab-verify__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
  }
}

.page-about .ab-verify__cell {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: linear-gradient(145deg, rgba(43, 42, 94, .48), rgba(4, 23, 15, .86));
}

.page-about .ab-verify__label {
  display: block;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .16em;
  color: var(--sage);
}

.page-about .ab-verify__value {
  display: block;
  margin-top: 8px;
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--mist);
  overflow-wrap: anywhere;
}

.page-about .ab-verify__actions {
  margin-top: 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .ab-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

.page-about .ab-btn .bsp-cta__arrow {
  transition: transform .2s ease;
}

.page-about .ab-btn:hover .bsp-cta__arrow,
.page-about .ab-btn:focus-visible .bsp-cta__arrow {
  transform: translateX(4px);
}

.page-about .ab-tick {
  margin-top: 8px;
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-rail__link,
  .page-about .ab-crumb a,
  .page-about .ab-layers__tab,
  .page-about .ab-tl__item,
  .page-about .ab-btn .bsp-cta__arrow {
    transition: none;
  }
}
<<<END>>>