.page-about {
  --ab-cut: 16px;
  --ab-gap: clamp(16px, 2.4vw, 28px);
  padding-bottom: clamp(48px, 8vw, 96px);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  display: grid;
  gap: 18px;
  padding: clamp(28px, 5vw, 64px) 0 clamp(26px, 4vw, 52px);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .ab-hero h1 {
  margin: 0;
  max-width: 15ch;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(36px, 8.2vw, 84px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--bone);
}

.page-about .ab-hero__lede {
  margin: 0;
  max-width: 48ch;
  color: var(--mist);
  font-size: 16px;
  line-height: 1.85;
}

.page-about .ab-hero__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 14px clamp(20px, 4vw, 48px);
  margin: 6px 0 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.page-about .ab-hero__facts li {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .ab-hero__num {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(22px, 3.2vw, 30px);
  letter-spacing: -0.01em;
  color: var(--bone);
}

.page-about .ab-hero__cap {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--stone);
}

.page-about .ab-hero__coord {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--moss-lit);
  opacity: 0.75;
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-sec {
  padding-top: clamp(46px, 7vw, 92px);
}

.page-about .ab-sec__head {
  max-width: 62ch;
  margin-bottom: clamp(20px, 3vw, 34px);
}

.page-about .ab-sec__head h2 {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(26px, 4.6vw, 44px);
  line-height: 1.14;
  letter-spacing: -0.015em;
  color: var(--bone);
}

.page-about .ab-sec__sub {
  margin: 14px 0 0;
  max-width: 56ch;
  color: var(--mist);
  font-size: 15px;
  line-height: 1.85;
}

.page-about .ab-sec__foot {
  margin: clamp(20px, 3vw, 30px) 0 0;
  font-size: 14px;
  color: var(--stone);
}

.page-about .ab-sec__foot a {
  color: var(--moss-lit);
  text-decoration: none;
  border-bottom: 1px solid rgba(79, 179, 155, 0.42);
  padding-bottom: 2px;
}

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

/* ---------- 图片容器 ---------- */
.page-about .ab-figure {
  margin: 0 0 clamp(24px, 3.6vw, 40px);
}

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

/* ---------- 时间线 ---------- */
.page-about .ab-timeline {
  position: relative;
  display: grid;
  gap: clamp(16px, 2.2vw, 24px);
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--moss) 0%, var(--moss-lit) 52%, var(--amber) 100%);
  opacity: 0.55;
  border-radius: 2px;
}

.page-about .ab-node {
  position: relative;
  padding-left: 32px;
}

.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: 0;
  top: 14px;
  width: 16px;
  height: 16px;
  background: var(--ink);
  border: 2px solid var(--moss-lit);
  transform: rotate(45deg);
  box-sizing: border-box;
}

.page-about .ab-node__box {
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 14px 16px 16px;
  clip-path: polygon(var(--ab-cut) 0, 100% 0, 100% 100%, 0 100%, 0 var(--ab-cut));
  transition: background var(--speed) ease, border-color var(--speed) ease;
}

.page-about .ab-node__box[open] {
  background: var(--lift);
  border-color: rgba(79, 179, 155, 0.34);
}

.page-about .ab-node__sum {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 12px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .ab-node__sum::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--stone);
  transition: color var(--speed) ease;
}

.page-about .ab-node__box[open] .ab-node__sum::after {
  content: "−";
  color: var(--signal);
}

.page-about .ab-node__code {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--moss-lit);
}

.page-about .ab-node__title {
  font-size: 16px;
  font-weight: 700;
  color: var(--bone);
  line-height: 1.5;
}

.page-about .ab-node__body {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--line);
}

.page-about .ab-node__body p {
  margin: 0;
  color: var(--mist);
  font-size: 15px;
  line-height: 1.85;
}

/* ---------- 覆盖与分流 ---------- */
.page-about .ab-cover {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
}

.page-about .ab-cover__lede {
  margin: 0;
  max-width: 54ch;
  color: var(--mist);
  font-size: 16px;
  line-height: 1.85;
}

.page-about .ab-cover__stats {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-cover__stats li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 0 12px 16px;
  border-left: 2px solid var(--moss);
}

.page-about .ab-cover__stats li:nth-child(2) {
  border-left-color: var(--moss-lit);
}

.page-about .ab-cover__stats li:nth-child(3) {
  border-left-color: var(--amber);
}

.page-about .ab-stat__num {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(22px, 3.2vw, 30px);
  letter-spacing: -0.01em;
  color: var(--bone);
}

.page-about .ab-stat__cap {
  font-size: 13px;
  line-height: 1.6;
  color: var(--stone);
}

.page-about .ab-zones {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(140px, 100%), 1fr));
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-zone {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 14px 16px;
  background: var(--panel);
  border: 1px solid var(--line);
  clip-path: polygon(12px 0, 100% 0, 100% 100%, 0 100%, 0 12px);
  transition: transform var(--speed) ease, background var(--speed) ease, border-color var(--speed) ease;
}

.page-about .ab-zone:hover,
.page-about .ab-zone:focus-within {
  transform: translateY(-2px);
  background: var(--lift);
  border-color: var(--signal);
}

.page-about .ab-zone__name {
  font-size: 16px;
  font-weight: 700;
  color: var(--bone);
}

.page-about .ab-zone__meta {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--stone);
}

.page-about .ab-zone:hover .ab-zone__meta {
  color: var(--amber);
}

.page-about .ab-zones__note {
  margin: 16px 0 0;
  max-width: 60ch;
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .ab-zones__note strong {
  font-family: var(--font-mono);
  font-weight: 500;
  color: var(--signal);
  letter-spacing: 0.06em;
}

/* ---------- 本地运维 ---------- */
.page-about .ab-ops {
  display: grid;
  gap: clamp(18px, 2.6vw, 28px);
}

.page-about .ab-figure--ops {
  margin-bottom: 0;
}

.page-about .ab-ops__cards {
  display: grid;
  gap: 14px;
}

.page-about .ab-card {
  padding: clamp(18px, 2.4vw, 26px);
  background: var(--panel);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, 100% 0, 100% 100%, var(--ab-cut) 100%, 0 calc(100% - var(--ab-cut)));
}

.page-about .ab-card h3 {
  margin: 8px 0 0;
  font-size: 18px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--bone);
}

.page-about .ab-card p:last-child {
  margin: 10px 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 团队分工 ---------- */
.page-about .ab-crew {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-crew__item {
  position: relative;
  padding: 24px 18px 20px;
  background: var(--panel);
  border: 1px solid var(--line);
}

.page-about .ab-crew__item::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--crew, var(--moss));
}

.page-about .ab-crew__item:nth-child(1) {
  --crew: var(--moss);
}

.page-about .ab-crew__item:nth-child(2) {
  --crew: var(--moss-lit);
}

.page-about .ab-crew__item:nth-child(3) {
  --crew: var(--amber);
}

.page-about .ab-crew__item:nth-child(4) {
  --crew: var(--clay);
}

.page-about .ab-crew__idx {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--stone);
}

.page-about .ab-crew__item h3 {
  margin: 10px 0 0;
  font-size: 18px;
  font-weight: 700;
  color: var(--bone);
}

.page-about .ab-crew__item p {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 后续方向 ---------- */
.page-about .ab-sec--next {
  margin-top: clamp(46px, 7vw, 88px);
  padding: clamp(28px, 4.4vw, 52px) clamp(20px, 3vw, 40px) clamp(26px, 4vw, 48px);
  background: linear-gradient(160deg, var(--lift) 0%, var(--panel) 62%, var(--panel) 100%);
  border: 1px solid var(--line);
  clip-path: polygon(var(--ab-cut) 0, 100% 0, 100% 100%, 0 100%, 0 var(--ab-cut));
}

.page-about .ab-next {
  display: grid;
  gap: 16px;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: abnext;
}

.page-about .ab-next li {
  position: relative;
  padding-left: 34px;
}

.page-about .ab-next li::before {
  counter-increment: abnext;
  content: counter(abnext, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 2px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--signal);
}

.page-about .ab-next h3 {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  color: var(--bone);
}

.page-about .ab-next p {
  margin: 6px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .ab-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3vw, 32px);
  padding-top: clamp(18px, 2.6vw, 26px);
  border-top: 1px solid var(--line);
}

/* ---------- 桌面布局 ---------- */
@media (min-width: 700px) {
  .page-about .ab-ops__cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .ab-crew {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero {
    padding-right: clamp(60px, 9vw, 140px);
  }

  .page-about .ab-hero__coord {
    position: absolute;
    top: clamp(40px, 6vw, 84px);
    right: 0;
    writing-mode: vertical-rl;
    letter-spacing: 0.3em;
    opacity: 0.6;
  }

  .page-about .ab-sec__head {
    max-width: 68ch;
  }

  .page-about .ab-cover {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: clamp(24px, 3.4vw, 48px);
    align-items: start;
  }

  .page-about .ab-ops {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    align-items: start;
  }

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

  /* 时间线左右交替 */
  .page-about .ab-timeline::before {
    left: 50%;
    transform: translateX(-1px);
  }

  .page-about .ab-node {
    width: calc(50% - 34px);
    padding-left: 0;
  }

  .page-about .ab-node:nth-child(odd) {
    justify-self: start;
  }

  .page-about .ab-node:nth-child(even) {
    justify-self: end;
  }

  .page-about .ab-node:nth-child(odd)::before {
    left: auto;
    right: -42px;
  }

  .page-about .ab-node:nth-child(even)::before {
    left: -42px;
  }
}

@media (min-width: 1100px) {
  .page-about .ab-crew {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .ab-next {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: clamp(20px, 3vw, 40px);
  }

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