.page-about {
  --ab-radius: 18px;
}

.page-about a:focus-visible,
.page-about summary:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 3px;
}

.page-about [data-section] {
  padding-block: clamp(28px, 4vw, 46px);
  border-top: 1px solid var(--line-light);
  scroll-margin-top: 112px;
}

.page-about [data-section]:first-child {
  border-top: 0;
  padding-top: 0;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  background: var(--ink-950);
  color: var(--white);
  padding: clamp(36px, 6vw, 84px) 0 clamp(44px, 7vw, 96px);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(255, 255, 255, .045) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, .045) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  right: -140px;
  top: -120px;
  width: 380px;
  height: 380px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(47, 212, 200, .18), transparent 68%);
  pointer-events: none;
}

.page-about .ab-hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(28px, 5vw, 56px);
}

.page-about .ab-hero .eyebrow {
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: .75rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  margin: 0;
}

.page-about .ab-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2.6rem, 8vw, 6.2rem);
  line-height: 1.02;
  letter-spacing: -.02em;
  margin: .22em 0 .42em;
  color: var(--white);
  overflow-wrap: break-word;
}

.page-about .ab-hero .lede {
  font-size: clamp(.9375rem, 1.5vw, 1.125rem);
  line-height: 1.78;
  color: rgba(255, 255, 255, .76);
  max-width: 46ch;
  margin: 0;
}

.page-about .ab-hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-hero-tags li {
  font-family: var(--font-mono);
  font-size: .8125rem;
  letter-spacing: .1em;
  padding: 7px 16px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, .2);
  background: rgba(255, 255, 255, .05);
  color: var(--celadon);
}

.page-about .ab-hero-tags li:nth-child(2) {
  color: var(--amber);
}

.page-about .ab-hero-tags li:nth-child(3) {
  color: var(--cyan);
}

.page-about .ab-hero-visual {
  position: relative;
  margin: 0;
}

.page-about .ab-hero-visual img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: 16px;
  border: 1px solid rgba(255, 255, 255, .14);
  background: var(--ink-800);
  object-fit: cover;
}

.page-about .ab-hero-cap {
  position: absolute;
  left: 12px;
  bottom: 12px;
  font-size: .6875rem;
  letter-spacing: .1em;
  padding: 6px 11px;
  border-radius: 6px;
  background: rgba(8, 24, 38, .8);
  border: 1px solid rgba(255, 255, 255, .16);
  color: var(--celadon);
}

/* ---------- 双栏工作台 ---------- */
.page-about .ab-layout {
  display: grid;
  gap: clamp(24px, 4vw, 48px);
  padding-block: clamp(36px, 5vw, 64px);
}

.page-about .ab-layout > * {
  min-width: 0;
}

.page-about .ab-toc {
  font-family: var(--font-mono);
}

.page-about .ab-toc .toc-title {
  font-size: .6875rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--slate);
  margin: 0 0 12px;
}

.page-about .ab-toc ul {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--line-light);
}

.page-about .ab-toc li {
  margin: 0;
}

.page-about .ab-toc a {
  display: block;
  padding: 8px 0 8px 14px;
  margin-left: -1px;
  border-left: 2px solid transparent;
  color: var(--slate);
  font-size: .8125rem;
  line-height: 1.5;
  text-decoration: none;
  transition: color var(--t) var(--ease), border-color var(--t) var(--ease);
}

.page-about .ab-toc a:hover,
.page-about .ab-toc a:focus-visible {
  color: var(--ink-950);
  border-left-color: var(--cyan);
}

.page-about .ab-toc a[aria-current],
.page-about .ab-toc a.is-active {
  color: var(--ink-950);
  border-left-color: var(--signal);
  font-weight: 500;
}

/* ---------- 正文 ---------- */
.page-about .ab-main h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.65rem, 3.4vw, 2.5rem);
  line-height: 1.1;
  letter-spacing: -.01em;
  color: var(--ink-950);
  margin: 0 0 .65em;
}

.page-about .ab-main p {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--slate);
  margin: 0 0 1em;
  max-width: 68ch;
}

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

.page-about .ab-main a {
  color: var(--ink-950);
  text-decoration: underline;
  text-decoration-color: var(--cyan);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
  transition: color var(--t) var(--ease), text-decoration-color var(--t) var(--ease);
}

.page-about .ab-main a:hover {
  color: var(--signal);
  text-decoration-color: var(--signal);
}

.page-about .ab-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  color: var(--ink-950);
}

/* ---------- 原则卡 ---------- */
.page-about .ab-principles {
  display: grid;
  gap: 18px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-principle {
  background: var(--white);
  border: 1px solid var(--line-light);
  border-radius: 14px;
  padding: 22px 20px;
  box-shadow: 0 1px 0 rgba(8, 24, 38, .04);
}

.page-about .ab-principle:nth-child(1) {
  border-top: 3px solid var(--cyan);
}

.page-about .ab-principle:nth-child(2) {
  border-top: 3px solid var(--amber);
}

.page-about .ab-principle:nth-child(3) {
  border-top: 3px solid var(--celadon);
}

.page-about .ab-principle-idx {
  display: block;
  font-family: var(--font-mono);
  font-size: .6875rem;
  letter-spacing: .16em;
  color: var(--slate);
  margin-bottom: 12px;
}

.page-about .ab-principle h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.5rem;
  line-height: 1.15;
  color: var(--ink-950);
  margin: 0 0 .55em;
}

.page-about .ab-main .ab-principle p {
  font-size: .9375rem;
  line-height: 1.75;
  margin-bottom: 0;
}

.page-about .ab-principle .ab-principle-gain {
  margin: 16px 0 0;
  padding: 10px 12px;
  border-radius: 8px;
  background: rgba(95, 191, 165, .14);
  color: var(--ink-900);
  font-size: .875rem;
  line-height: 1.6;
}

/* ---------- 流程 ---------- */
.page-about .ab-process {
  display: grid;
  gap: 24px;
  margin-top: 26px;
}

.page-about .ab-process-fig {
  margin: 0;
}

.page-about .ab-process-fig img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: 12px;
  border: 1px solid var(--line-light);
  background: var(--paper-100);
  object-fit: cover;
}

.page-about .ab-steps {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-steps li {
  position: relative;
  padding: 2px 0 22px 52px;
}

.page-about .ab-steps li::before {
  content: "";
  position: absolute;
  left: 15px;
  top: 32px;
  bottom: 0;
  width: 1px;
  background: linear-gradient(to bottom, rgba(8, 24, 38, .22), transparent);
}

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

.page-about .ab-steps li:last-child::before {
  display: none;
}

.page-about .ab-step-idx {
  position: absolute;
  left: 0;
  top: 0;
  width: 31px;
  height: 31px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  border: 1px solid var(--ink-950);
  color: var(--ink-950);
  font-size: .6875rem;
  letter-spacing: .04em;
  background: var(--paper-050);
}

.page-about .ab-steps h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  line-height: 1.25;
  color: var(--ink-950);
  margin: 0 0 .4em;
}

.page-about .ab-main .ab-steps p {
  font-size: .9375rem;
  margin-bottom: 0;
}

/* ---------- 团队 ---------- */
.page-about .ab-team {
  background: var(--ink-900);
  border-radius: var(--ab-radius);
  padding: clamp(22px, 4vw, 40px);
  color: var(--white);
}

.page-about .ab-team h2 {
  color: var(--white);
}

.page-about .ab-team p {
  color: rgba(255, 255, 255, .74);
}

.page-about .ab-team a {
  color: var(--cyan);
  text-decoration-color: currentColor;
}

.page-about .ab-team a:hover {
  color: var(--signal);
  text-decoration-color: var(--signal);
}

.page-about .ab-team .ab-num {
  color: var(--white);
}

.page-about .ab-stats {
  list-style: none;
  margin: 26px 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: rgba(255, 255, 255, .12);
  border-radius: 12px;
  overflow: hidden;
}

.page-about .ab-stat {
  background: var(--ink-800);
  padding: 18px;
}

.page-about .ab-team .ab-stat-num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.55rem, 3vw, 2.05rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--white);
}

.page-about .ab-team .ab-stat-num small {
  font-size: .48em;
  margin-left: 4px;
  font-weight: 500;
  color: var(--celadon);
  letter-spacing: 0;
}

.page-about .ab-team .ab-stat-label {
  display: block;
  margin-top: 9px;
  font-size: .8125rem;
  line-height: 1.5;
  color: rgba(255, 255, 255, .6);
}

/* ---------- 时间线 ---------- */
.page-about .ab-timeline {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  position: relative;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 10px;
  bottom: 14px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(to bottom, var(--signal), var(--cyan) 46%, var(--celadon));
  opacity: .55;
}

.page-about .ab-node {
  position: relative;
  padding: 0 0 22px 34px;
}

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

.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: 0;
  top: 5px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--paper-050);
  border: 2px solid var(--ink-950);
  z-index: 1;
}

.page-about .ab-phase {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .6875rem;
  letter-spacing: .14em;
  color: var(--ink-950);
  background: var(--paper-100);
  padding: 3px 9px;
  border-radius: 4px;
  margin-bottom: 8px;
}

.page-about .ab-node summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  align-items: baseline;
  justify-content: space-between;
  padding: 2px 0;
}

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

.page-about .ab-node-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.15rem, 2vw, 1.4rem);
  line-height: 1.25;
  color: var(--ink-950);
}

.page-about .ab-node-hint {
  font-family: var(--font-mono);
  font-size: .6875rem;
  letter-spacing: .06em;
  color: var(--slate);
  border-bottom: 1px dashed currentColor;
  white-space: nowrap;
}

.page-about .ab-node-hint::after {
  content: "展开摘要";
}

.page-about .ab-node details[open] .ab-node-hint {
  color: var(--signal);
}

.page-about .ab-node details[open] .ab-node-hint::after {
  content: "收起摘要";
}

.page-about .ab-main .ab-node details p {
  margin: 12px 0 0;
  font-size: .9375rem;
}

/* ---------- 区域与备案 ---------- */
.page-about .ab-region {
  background: var(--ink-950);
  color: var(--white);
  border-radius: var(--ab-radius);
  padding: clamp(22px, 4vw, 40px);
}

.page-about .ab-region h2 {
  color: var(--white);
}

.page-about .ab-region p {
  color: rgba(255, 255, 255, .74);
}

.page-about .ab-region a {
  color: var(--cyan);
  text-decoration-color: currentColor;
}

.page-about .ab-region a:hover {
  color: var(--signal);
  text-decoration-color: var(--signal);
}

.page-about .ab-icp {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-top: 6px;
  padding: 10px 14px;
  border: 1px solid rgba(255, 255, 255, .18);
  border-radius: 10px;
  background: rgba(255, 255, 255, .05);
  font-size: .8125rem;
  color: rgba(255, 255, 255, .62);
}

.page-about .ab-icp .mono {
  color: var(--celadon);
  font-family: var(--font-mono);
  letter-spacing: .06em;
}

/* ---------- 结尾行动 ---------- */
.page-about .ab-cta {
  margin-top: clamp(32px, 5vw, 52px);
  padding: clamp(22px, 4vw, 34px);
  border: 1px solid var(--line-light);
  border-radius: var(--ab-radius);
  background: var(--white);
  display: grid;
  gap: 18px;
}

.page-about .ab-cta-lead {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.1rem, 2vw, 1.35rem);
  line-height: 1.35;
  color: var(--ink-950);
}

.page-about .ab-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */
@media (max-width: 979px) {
  .page-about .ab-toc ul {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    border-left: 0;
    padding-bottom: 6px;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
  }

  .page-about .ab-toc a {
    white-space: nowrap;
    margin-left: 0;
    padding: 6px 12px;
    border: 1px solid var(--line-light);
    border-left-width: 1px;
    border-radius: 999px;
  }

  .page-about .ab-toc a[aria-current],
  .page-about .ab-toc a.is-active {
    border-color: var(--signal);
  }
}

@media (min-width: 640px) {
  .page-about .ab-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

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

  .page-about .ab-principle:nth-child(2) {
    margin-top: 26px;
  }

  .page-about .ab-principle:nth-child(3) {
    margin-top: 52px;
  }
}

@media (min-width: 860px) {
  .page-about .ab-process {
    grid-template-columns: minmax(0, 5fr) minmax(0, 6fr);
    align-items: start;
    gap: 34px;
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero-grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: center;
  }
}

@media (min-width: 980px) {
  .page-about .ab-layout {
    grid-template-columns: minmax(180px, 236px) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .ab-toc {
    position: sticky;
    top: 96px;
    align-self: start;
  }

  .page-about .ab-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-toc a,
  .page-about .ab-main a {
    transition: none;
  }
}
<<<END>>>