.page-about {
  --ab-node-spring: #7FE3CE;
  --ab-node-summer: #FF9A6B;
  --ab-node-autumn: #F0C14B;
  --ab-node-winter: #93B4FF;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.8;
  overflow-x: clip;
}

.page-about .breadcrumbs {
  padding-top: 20px;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  padding-block: clamp(22px, 4vw, 40px) clamp(30px, 5vw, 60px);
}

.page-about .ab-hero__cut {
  position: absolute;
  top: 0;
  right: 0;
  width: min(56%, 660px);
  height: clamp(170px, 24vw, 300px);
  background: var(--spring);
  opacity: .13;
  clip-path: polygon(24% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

.page-about .ab-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(18px, 3vw, 40px);
  grid-template-columns: 1fr;
}

.page-about .ab-hero__title {
  margin: 10px 0 0;
  font-size: clamp(36px, 6.2vw, 76px);
  line-height: 1.05;
  letter-spacing: -.02em;
  font-weight: 900;
}

.page-about .ab-hero__intro p {
  margin: 0 0 22px;
  max-width: 40ch;
  color: var(--ink);
}

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

.page-about .ab-digits {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 20px;
  grid-template-columns: 1fr;
  margin-top: clamp(28px, 4vw, 52px);
  padding-top: 22px;
  border-top: var(--line);
}

.page-about .ab-digit__value {
  display: block;
  font-size: clamp(34px, 4.4vw, 58px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.01em;
}

.page-about .ab-digit__label {
  display: block;
  margin-top: 10px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
  max-width: 26ch;
}

/* ---------- 通用区块 ---------- */
.page-about .ab-section {
  padding-block: clamp(42px, 6vw, 88px);
  border-top: var(--line);
}

.page-about .ab-section--panel {
  background: var(--panel);
}

.page-about .ab-section--winter {
  background: var(--winter);
  color: #fff;
}

.page-about .ab-section__head {
  max-width: 780px;
}

.page-about .ab-h2 {
  margin: 8px 0 14px;
  font-size: clamp(26px, 3.6vw, 46px);
  line-height: 1.12;
  letter-spacing: -.02em;
  font-weight: 900;
}

.page-about .ab-lede {
  margin: 0 0 6px;
  max-width: 62ch;
  font-size: 17px;
  line-height: 1.8;
}

/* ---------- 3:9 与变体分栏 ---------- */
.page-about .ab-split {
  display: grid;
  gap: clamp(20px, 3vw, 38px);
  grid-template-columns: 1fr;
}

.page-about .ab-aside {
  align-self: start;
  border-top: 6px solid var(--spring);
  padding-top: 12px;
}

.page-about .ab-section--summer .ab-aside {
  border-top-color: var(--summer);
}

.page-about .ab-aside__num {
  margin: 0;
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
}

.page-about .ab-aside__label {
  margin: 8px 0 0;
  font-size: 16px;
  font-weight: 700;
}

.page-about .ab-aside__note {
  margin: 6px 0 0;
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--muted);
}

/* ---------- 档位卡片 ---------- */
.page-about .ab-tiers {
  display: grid;
  gap: 20px;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  margin-top: 30px;
}

.page-about .ab-tier {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.page-about .ab-tier__code {
  font-size: 13px;
  color: var(--muted);
}

.page-about .ab-tier__spec {
  margin: 0;
  display: grid;
  gap: 10px;
}

.page-about .ab-tier__spec > div {
  display: grid;
  grid-template-columns: 78px 1fr;
  gap: 10px;
  align-items: baseline;
  padding-top: 10px;
  border-top: var(--line-thin);
}

.page-about .ab-tier__spec dt {
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--muted);
}

.page-about .ab-tier__spec dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
}

/* ---------- 编号结构 ---------- */
.page-about .ab-code {
  margin-top: 28px;
  padding: clamp(16px, 3vw, 30px);
  background: #fff;
  border: var(--line);
  box-shadow: var(--shadow-hard);
  overflow-x: auto;
}

.page-about .ab-code__svg {
  display: block;
  width: 100%;
  min-width: 540px;
  height: auto;
}

.page-about .ab-code__legend {
  margin-top: 30px;
}

.page-about .ab-field {
  border-top: 5px solid var(--autumn);
  padding-top: 14px;
}

.page-about .ab-field:nth-child(2) {
  border-top-color: var(--winter);
}

.page-about .ab-field:nth-child(3) {
  border-top-color: var(--spring);
}

.page-about .ab-field__head {
  margin: 0 0 8px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .04em;
}

.page-about .ab-field p:last-child {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
}

.page-about .ab-code__sample {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin: 32px 0 0;
  padding: 16px 18px;
  background: var(--hl);
  border: var(--line);
}

.page-about .ab-code__value {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: .04em;
}

/* ---------- 时间线 ---------- */
.page-about .ab-section--winter .ab-h2,
.page-about .ab-section--winter .ab-lede {
  color: #fff;
}

.page-about .ab-section--winter .eyebrow {
  color: rgba(255, 255, 255, .72);
}

.page-about .ab-timeline {
  margin-top: clamp(30px, 4vw, 52px);
}

.page-about .ab-timeline__track {
  display: grid;
  gap: 34px;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
}

.page-about .ab-node {
  position: relative;
  padding-top: 28px;
  border-top: 2px solid rgba(255, 255, 255, .4);
}

.page-about .ab-node::before {
  content: "";
  position: absolute;
  top: -11px;
  left: 0;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--ab-node-spring);
  border: 3px solid var(--winter);
}

.page-about .ab-node:nth-child(2)::before {
  background: var(--ab-node-summer);
}

.page-about .ab-node:nth-child(3)::before {
  background: var(--ab-node-autumn);
}

.page-about .ab-node:nth-child(4)::before {
  background: var(--ab-node-winter);
}

.page-about .ab-node__year {
  margin: 0;
  font-size: clamp(28px, 3.4vw, 42px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.01em;
  color: #fff;
}

.page-about .ab-node__title {
  margin: 12px 0 8px;
  font-size: 18px;
  font-weight: 900;
  line-height: 1.4;
  color: #fff;
}

.page-about .ab-node__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: rgba(255, 255, 255, .84);
}

/* ---------- 沈阳清单 ---------- */
.page-about .ab-checklist {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.page-about .ab-checklist li {
  display: grid;
  gap: 4px;
  padding: 14px 16px;
  background: var(--hl);
  border-left: 5px solid var(--summer);
  font-size: 15px;
  line-height: 1.75;
}

.page-about .ab-checklist__k {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: .02em;
}

.page-about .ab-figure {
  margin: 28px 0 0;
}

.page-about .ab-figure--wide {
  margin-top: 30px;
}

/* ---------- 岗位分工 ---------- */
.page-about .ab-roles {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  margin-top: 24px;
}

.page-about .ab-role {
  padding-top: 12px;
  border-top: 4px solid var(--ink);
}

.page-about .ab-role__name {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 900;
}

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

.page-about .ab-note {
  margin: 24px 0 0;
  padding-left: 16px;
  border-left: 3px solid var(--autumn);
  font-size: 15px;
  line-height: 1.85;
}

/* ---------- 成都 ---------- */
.page-about .ab-chengdu {
  margin-top: clamp(24px, 3vw, 40px);
  align-items: start;
}

.page-about .ab-chengdu p {
  margin: 0 0 14px;
}

.page-about .ab-contact {
  background: #fff;
  border: var(--line);
  box-shadow: var(--shadow-soft);
  padding: 20px;
}

.page-about .ab-contact__row {
  display: grid;
  gap: 4px;
  margin: 0 0 14px;
  padding-bottom: 12px;
  border-bottom: var(--line-thin);
  font-size: 15px;
  line-height: 1.7;
}

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

.page-about .ab-contact__tip {
  margin: 0 0 16px;
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 后续入口 ---------- */
.page-about .ab-next {
  background: var(--paper);
}

.page-about .ab-next__grid {
  margin-top: 28px;
}

.page-about .ab-next__card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  text-decoration: none;
  color: inherit;
}

.page-about .ab-next__num {
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--muted);
}

.page-about .ab-next__name {
  font-size: 19px;
  font-weight: 900;
}

.page-about .ab-next__desc {
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .ab-next__card:hover {
  border-color: var(--spring);
}

.page-about .ab-next__card:nth-child(2):hover {
  border-color: var(--summer);
}

.page-about .ab-next__card:nth-child(3):hover {
  border-color: var(--autumn);
}

.page-about .ab-next__card:nth-child(4):hover {
  border-color: var(--winter);
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .ab-digits {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about .ab-digit + .ab-digit {
    padding-left: 20px;
    border-left: var(--line-thin);
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: 7fr 5fr;
    align-items: end;
  }

  .page-about .ab-split {
    grid-template-columns: 3fr 9fr;
  }

  .page-about .ab-split--even {
    grid-template-columns: 5fr 7fr;
    align-items: start;
  }

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

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

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

@media (max-width: 519px) {
  .page-about {
    font-size: 16px;
  }

  .page-about .ab-tier__spec > div {
    grid-template-columns: 1fr;
    gap: 2px;
  }

  .page-about .ab-code__sample {
    gap: 10px;
  }

  .page-about .ab-code__value {
    font-size: 19px;
  }
}