.page-about {
  --ab-rail: 88px;
  --ab-gap: 28px;
  background: var(--snow);
  color: var(--ink-text);
}

.page-about .ab-chapter__body,
.page-about .ab-chapter__title,
.page-about .ab-flip__text {
  overflow-wrap: break-word;
}

/* ============ 首屏 ============ */
.page-about .ab-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: 30px 0 52px;
  background:
    radial-gradient(120% 92% at 88% 6%, rgba(63, 134, 216, .42) 0%, rgba(63, 134, 216, 0) 58%),
    linear-gradient(124deg, var(--ink-950) 0%, var(--ink-800) 52%, var(--blue-700) 100%);
  color: var(--snow);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: -30% -12%;
  z-index: -1;
  background-image:
    repeating-linear-gradient(112deg, rgba(220, 232, 246, .075) 0 1px, transparent 1px 46px),
    repeating-linear-gradient(22deg, rgba(220, 232, 246, .05) 0 1px, transparent 1px 46px);
  pointer-events: none;
}

.page-about .ab-hero__inner {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
  align-items: start;
}

.page-about .ab-hero .bb-breadcrumb__link,
.page-about .ab-hero .bb-breadcrumb__current {
  color: rgba(220, 232, 246, .68);
}

.page-about .ab-hero .bb-breadcrumb__link:hover {
  color: var(--snow);
}

.page-about .ab-hero__kicker {
  color: var(--signal-soft);
}

.page-about .ab-hero__title {
  margin: 12px 0 0;
  max-width: 19ch;
  font-family: var(--font-display);
  font-size: clamp(29px, 4.8vw, 54px);
  font-weight: 900;
  line-height: 1.08;
  letter-spacing: -.02em;
  color: var(--snow);
}

.page-about .ab-hero__lede {
  margin: 20px 0 0;
  max-width: 58ch;
  font-size: clamp(15px, 1.05vw, 17px);
  line-height: 1.85;
  letter-spacing: .01em;
  color: rgba(220, 232, 246, .86);
}

.page-about .ab-hero__facts {
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--line-dark);
  border-bottom: 1px solid var(--line-dark);
}

.page-about .ab-hero__facts > li {
  padding: 15px 12px;
  border-right: 1px solid var(--line-dark);
}

.page-about .ab-hero__facts > li:first-child {
  padding-left: 0;
}

.page-about .ab-hero__facts > li:last-child {
  border-right: 0;
}

.page-about .ab-hero .bb-stat__value {
  color: var(--snow);
}

.page-about .ab-hero .bb-stat__value--signal {
  color: var(--signal);
}

.page-about .ab-hero .bb-stat__label {
  color: rgba(220, 232, 246, .64);
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about .ab-hero__figure {
  position: relative;
  margin: 0;
  padding: 10px;
  border: 1px solid rgba(220, 232, 246, .22);
  background: rgba(10, 22, 38, .34);
  box-shadow: 14px 14px 0 rgba(255, 106, 26, .14);
}

.page-about .ab-corner {
  position: absolute;
  top: -1px;
  right: -1px;
  z-index: 2;
  padding: 5px 11px;
  background: var(--signal);
  color: #fff;
  font-size: 11px;
  letter-spacing: .08em;
}

.page-about .ab-hero__caption {
  margin: 12px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(220, 232, 246, .62);
}

/* ============ 媒体容器 ============ */
.page-about .ab-media {
  position: relative;
  overflow: hidden;
  background: linear-gradient(140deg, var(--ink-800), var(--blue-700));
}

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

.page-about .ab-media--3x4 img {
  aspect-ratio: 3 / 4;
}

.page-about .ab-media--3x2 img {
  aspect-ratio: 3 / 2;
}

.page-about .ab-media--10x7 img {
  aspect-ratio: 10 / 7;
}

/* ============ 章节导航 ============ */
.page-about .ab-toc {
  position: sticky;
  top: var(--topbar-h);
  z-index: 4;
  background: rgba(247, 250, 253, .94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(8px);
}

.page-about .ab-toc__inner {
  display: flex;
  align-items: center;
  gap: 22px;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .ab-toc__inner::-webkit-scrollbar {
  display: none;
}

.page-about .ab-toc__link {
  flex: 0 0 auto;
  padding: 13px 2px 11px;
  border-bottom: 2px solid transparent;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .05em;
  color: var(--grid-grey);
  text-decoration: none;
  white-space: nowrap;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.page-about .ab-toc__link:hover,
.page-about .ab-toc__link.is-active {
  color: var(--ink-text);
  border-bottom-color: var(--signal);
}

/* ============ 章节骨架 ============ */
.page-about .ab-chapter {
  position: relative;
  padding: 58px 0;
  border-top: 1px solid var(--line);
}

.page-about .ab-chapter--tint {
  background: linear-gradient(180deg, rgba(220, 232, 246, .56), rgba(220, 232, 246, .16));
  border-top-color: rgba(30, 78, 140, .18);
}

.page-about .ab-chapter--last {
  padding-bottom: 72px;
}

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

.page-about .ab-chapter__rail {
  display: flex;
  align-items: center;
  gap: 16px;
}

.page-about .ab-chapter__num {
  font-family: var(--font-mono);
  font-size: clamp(34px, 4.4vw, 58px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.05em;
  color: var(--blue-700);
}

@supports (-webkit-text-stroke: 1px red) {
  .page-about .ab-chapter__num {
    color: transparent;
    -webkit-text-stroke: 1.4px var(--blue-700);
  }
}

.page-about .ab-chapter__rule {
  flex: 1 1 auto;
  height: 1px;
  background: linear-gradient(90deg, var(--signal), rgba(255, 106, 26, 0));
}

.page-about .ab-chapter__body {
  max-width: 66ch;
}

.page-about .ab-chapter__title {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-size: clamp(23px, 2.7vw, 34px);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -.02em;
  color: var(--ink-text);
}

.page-about .ab-chapter__lead {
  color: var(--grid-grey);
}

.page-about .ab-chapter__body p {
  margin: 0 0 15px;
  font-size: 16.5px;
  line-height: 1.85;
  letter-spacing: .01em;
  color: var(--ink-text);
}

.page-about .ab-chapter__body strong {
  color: var(--blue-700);
  font-weight: 700;
}

.page-about .ab-chapter__more {
  margin-top: 22px;
  font-size: 14.5px;
  color: var(--grid-grey);
}

.page-about .ab-chapter__more a {
  color: var(--blue-700);
  text-decoration: none;
  border-bottom: 1px solid rgba(30, 78, 140, .34);
}

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

/* ============ 引用卡 ============ */
.page-about .ab-quote {
  position: relative;
  margin: 28px 0 0;
  padding: 26px 26px 24px 30px;
  background: var(--snow);
  border: 1px solid var(--line);
  box-shadow: 8px 8px 0 rgba(30, 78, 140, .09), 16px 16px 0 rgba(30, 78, 140, .045);
}

.page-about .ab-quote::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: linear-gradient(180deg, var(--signal), var(--signal-soft));
}

.page-about .ab-quote p {
  margin: 0;
  font-size: 17px;
  line-height: 1.8;
  color: var(--ink-text);
}

.page-about .ab-quote__cite {
  display: block;
  margin-top: 14px;
  font-size: 12px;
  font-style: normal;
  letter-spacing: .06em;
  color: var(--grid-grey);
}

/* ============ 价值主张翻卡 ============ */
.page-about .ab-values {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
  margin-top: 30px;
}

.page-about .ab-flip {
  perspective: 1600px;
  outline: none;
}

.page-about .ab-flip__inner {
  position: relative;
  min-height: 296px;
  transform-style: preserve-3d;
  transition: transform .44s var(--ease);
}

.page-about .ab-flip__face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 24px 22px;
  background: var(--snow);
  border: 1px solid var(--line);
  box-shadow: 9px 9px 0 rgba(30, 78, 140, .08);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

.page-about .ab-flip__front::after {
  content: "";
  position: absolute;
  top: -1px;
  right: -1px;
  width: 24px;
  height: 24px;
  background: linear-gradient(225deg, var(--signal) 0 50%, transparent 50%);
}

.page-about .ab-flip__back {
  transform: rotateY(180deg);
  background: linear-gradient(158deg, var(--ink-800) 0%, var(--blue-700) 100%);
  border-color: rgba(220, 232, 246, .18);
  color: var(--snow);
  box-shadow: 9px 9px 0 rgba(10, 22, 38, .18);
}

.page-about .ab-flip__index {
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--signal);
}

.page-about .ab-flip__title {
  margin: 0;
  font-size: 21px;
  font-weight: 900;
  letter-spacing: -.01em;
  color: var(--ink-text);
}

.page-about .ab-flip__back .ab-flip__title {
  color: var(--snow);
  font-size: 16px;
  letter-spacing: .04em;
}

.page-about .ab-flip__back .ab-flip__title::before {
  content: "";
  display: block;
  width: 26px;
  height: 3px;
  margin-bottom: 12px;
  background: var(--signal);
}

.page-about .ab-flip__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.82;
  color: var(--ink-text);
}

.page-about .ab-flip__back .ab-flip__text {
  color: rgba(220, 232, 246, .86);
}

.page-about .ab-flip__hint {
  margin-top: auto;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--grid-grey);
}

.page-about .ab-flip__tag {
  margin-top: auto;
  align-self: flex-start;
  padding: 4px 10px;
  border: 1px solid rgba(111, 227, 166, .48);
  color: var(--neon);
  font-size: 11.5px;
  letter-spacing: .06em;
}

@media (min-width: 860px) {
  .page-about .ab-values {
    grid-template-columns: 5fr 3fr 4fr;
    gap: 22px;
    align-items: start;
  }

  .page-about .ab-flip:nth-child(2) {
    transform: translateY(14px);
  }

  .page-about .ab-flip:nth-child(3) {
    transform: translateY(24px);
  }

  .page-about .ab-flip:hover .ab-flip__inner,
  .page-about .ab-flip:focus-visible .ab-flip__inner {
    transform: rotateY(180deg);
  }
}

/* ============ 数据来源索引 ============ */
.page-about .ab-sources {
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .ab-sources__row {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr);
  gap: 6px 14px;
  align-items: baseline;
  padding: 16px 4px;
  border-bottom: 1px solid var(--line);
  transition: transform .18s var(--ease), background-color .18s var(--ease);
}

.page-about .ab-sources__row:hover {
  transform: translateX(4px);
  background: rgba(30, 78, 140, .05);
}

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

.page-about .ab-sources__name {
  font-size: 15.5px;
  font-weight: 700;
  color: var(--ink-text);
}

.page-about .ab-sources__meta {
  font-size: 14px;
  line-height: 1.72;
  color: var(--grid-grey);
}

.page-about .ab-sources__value {
  font-size: 12.5px;
  letter-spacing: .04em;
  color: var(--blue-700);
}

@media (min-width: 760px) {
  .page-about .ab-sources__row {
    grid-template-columns: 64px minmax(0, 1.05fr) minmax(0, 1.5fr) 92px;
    align-items: center;
  }
}

/* ============ 图片 ============ */
.page-about .ab-figure {
  margin: 30px 0 0;
}

.page-about .ab-figure .ab-media {
  border: 1px solid var(--line);
}

.page-about .ab-figure__caption {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--grid-grey);
}

/* ============ 用户错位网格 ============ */
.page-about .ab-users {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  margin-top: 30px;
}

.page-about .ab-user {
  padding: 22px 20px;
  background: var(--snow);
  border: 1px solid var(--line);
  border-left: 3px solid var(--blue-700);
  box-shadow: 7px 7px 0 rgba(30, 78, 140, .07);
}

.page-about .ab-user:nth-child(2) {
  border-left-color: var(--blue-500);
}

.page-about .ab-user:nth-child(3) {
  border-left-color: var(--neon-deep);
}

.page-about .ab-user:nth-child(4) {
  border-left-color: var(--signal);
}

.page-about .ab-user__tag {
  display: inline-block;
  margin-bottom: 8px;
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--signal);
}

.page-about .ab-user__title {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 800;
  line-height: 1.4;
  color: var(--ink-text);
}

.page-about .ab-user__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--grid-grey);
}

@media (min-width: 900px) {
  .page-about .ab-users {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: 20px;
  }

  .page-about .ab-user:nth-child(1) {
    grid-column: 1 / span 7;
  }

  .page-about .ab-user:nth-child(2) {
    grid-column: 8 / span 5;
  }

  .page-about .ab-user:nth-child(3) {
    grid-column: 2 / span 5;
  }

  .page-about .ab-user:nth-child(4) {
    grid-column: 7 / span 6;
  }
}

/* ============ 版本节点横向轨道 ============ */
.page-about .ab-track {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(232px, 74%);
  gap: 0;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  overscroll-behavior-x: contain;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  scrollbar-width: thin;
}

.page-about .ab-track__node {
  scroll-snap-align: start;
  padding: 22px 20px 26px;
  border-right: 1px solid var(--line);
  background: var(--snow);
  transition: background-color .2s var(--ease), box-shadow .2s var(--ease);
}

.page-about .ab-track__node:last-child {
  border-right: 0;
}

.page-about .ab-track__node:hover,
.page-about .ab-track__node:focus-within {
  background: rgba(30, 78, 140, .05);
  box-shadow: inset 0 3px 0 var(--signal);
}

.page-about .ab-track__ver {
  display: inline-block;
  padding: 3px 8px;
  border: 1px solid rgba(255, 106, 26, .34);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--signal);
}

.page-about .ab-track__title {
  margin: 14px 0 8px;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.38;
  color: var(--ink-text);
}

.page-about .ab-track__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--grid-grey);
}

.page-about .ab-track__hint {
  margin: 12px 0 0;
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--grid-grey);
}

@media (min-width: 900px) {
  .page-about .ab-track {
    grid-auto-columns: minmax(210px, 25%);
  }
}

/* ============ 团队与协作 ============ */
.page-about .ab-bars {
  margin: 26px 0 0;
  border-top: 1px solid var(--line);
}

.page-about .ab-bar {
  display: grid;
  grid-template-columns: 92px minmax(0, 1fr) 58px;
  align-items: center;
  gap: 14px;
  padding: 15px 2px;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-bar__name {
  font-size: 14.5px;
  font-weight: 700;
  color: var(--ink-text);
}

.page-about .ab-bar__track {
  position: relative;
  height: 8px;
  background: var(--mist-200);
  overflow: hidden;
}

.page-about .ab-bar__fill {
  position: absolute;
  inset: 0 auto 0 0;
  width: var(--fill, 0%);
  background: linear-gradient(90deg, var(--blue-700), var(--blue-500));
}

.page-about .ab-bar__fill--signal {
  background: linear-gradient(90deg, var(--signal), var(--signal-soft));
}

.page-about .ab-bar__value {
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--blue-700);
  text-align: right;
}

.page-about .ab-eco {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin-top: 28px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-eco__item {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 18px;
  background: var(--snow);
}

.page-about .ab-eco__value {
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
  color: var(--signal);
}

.page-about .ab-eco__name {
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--ink-text);
}

.page-about .ab-cta {
  display: grid;
  gap: 18px;
  margin-top: 32px;
  padding: 26px 24px;
  border: 1px solid rgba(30, 78, 140, .24);
  background: linear-gradient(150deg, rgba(30, 78, 140, .09), rgba(255, 106, 26, .07));
  box-shadow: 10px 10px 0 rgba(30, 78, 140, .07);
}

.page-about .ab-cta__title {
  margin: 0 0 8px;
  font-size: 20px;
  font-weight: 900;
  line-height: 1.35;
  color: var(--ink-text);
}

.page-about .ab-cta__desc {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--grid-grey);
}

.page-about .ab-cta .bb-btn {
  justify-self: start;
}

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

  .page-about .ab-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: 30px;
  }
}

/* ============ 桌面栅格与错位 ============ */
@media (min-width: 880px) {
  .page-about .ab-hero__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 52px;
    align-items: end;
  }

  .page-about .ab-chapter__grid {
    grid-template-columns: var(--ab-rail) minmax(0, 1fr);
    gap: var(--ab-gap);
  }

  .page-about .ab-chapter__rail {
    align-self: stretch;
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }

  .page-about .ab-chapter__rule {
    flex: 0 0 auto;
    width: 1px;
    height: 64px;
    background: linear-gradient(180deg, var(--signal), rgba(255, 106, 26, 0));
  }

  .page-about .ab-chapter__body--wide {
    max-width: 78ch;
  }
}

@media (min-width: 1160px) {
  .page-about .ab-chapter--tint .ab-chapter__body {
    padding-left: 4%;
  }

  .page-about .ab-chapter--last .ab-chapter__body {
    max-width: 72ch;
  }
}

/* ============ 触屏降级：翻卡改为上下堆叠 ============ */
@media (hover: none) {
  .page-about .ab-flip {
    transform: none;
  }

  .page-about .ab-flip__inner {
    min-height: 0;
    transform: none;
    transform-style: flat;
  }

  .page-about .ab-flip__face {
    position: static;
    inset: auto;
    transform: none;
    backface-visibility: visible;
    -webkit-backface-visibility: visible;
  }

  .page-about .ab-flip__face + .ab-flip__face {
    margin-top: -1px;
  }

  .page-about .ab-flip__back {
    transform: none;
  }

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

/* ============ 动效克制 ============ */
@media (prefers-reduced-motion: reduce) {
  .page-about .ab-flip__inner,
  .page-about .ab-sources__row,
  .page-about .ab-track__node,
  .page-about .ab-toc__link {
    transition: none;
  }
}
<<<END>>>

.page-about {
  --fill: currentColor;
}