.page-about {
  --ab-gap: clamp(40px, 6vw, 88px);
  --ab-accent: var(--ember);
  --ab-node-accent: var(--ember);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  margin: 0 0 var(--ab-gap);
  background: var(--ink);
  color: var(--paper);
  overflow: hidden;
  clip-path: polygon(0 0, calc(100% - 26px) 0, 100% 26px, 100% 100%, 0 100%);
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(
    115deg,
    transparent 0 36px,
    rgba(196, 240, 66, 0.07) 36px 37px
  );
}

.page-about .ab-hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 32px;
  padding-top: clamp(36px, 6vw, 80px);
  padding-bottom: clamp(36px, 6vw, 72px);
}

.page-about .ab-hero__kicker {
  margin: 0;
  font-size: 13px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--volt);
}

.page-about .ab-hero__title {
  margin: 14px 0 18px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(36px, 7.5vw, 84px);
  line-height: 1.06;
  letter-spacing: -0.012em;
  transform: scaleX(0.96);
  transform-origin: left center;
}

.page-about .ab-hero__lede {
  margin: 0;
  max-width: 36em;
  font-size: clamp(16px, 1.6vw, 17px);
  line-height: 1.78;
  color: rgba(243, 238, 226, 0.8);
}

.page-about .ab-hero__track {
  list-style: none;
  margin: 0;
  padding: 0 0 0 18px;
  border-left: 2px solid rgba(243, 238, 226, 0.18);
  display: grid;
  gap: 0;
}

.page-about .ab-hero__track-item {
  display: grid;
  grid-template-columns: 30px 66px minmax(0, 1fr);
  align-items: baseline;
  gap: 10px;
  padding: 11px 0;
  border-bottom: 1px solid rgba(243, 238, 226, 0.14);
}

.page-about .ab-hero__track-item:last-child {
  border-bottom: 0;
}

.page-about .ab-hero__track-num {
  font-size: 12px;
  color: var(--volt);
  letter-spacing: 0.06em;
}

.page-about .ab-hero__track-ver {
  font-size: 13px;
  color: var(--paper);
  letter-spacing: 0.04em;
}

.page-about .ab-hero__track-tag {
  font-size: 14px;
  line-height: 1.5;
  color: rgba(243, 238, 226, 0.72);
}

@media (min-width: 900px) {
  .page-about .ab-hero__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    gap: clamp(36px, 5vw, 80px);
    align-items: end;
  }
}

/* ---------- 分段切换 ---------- */
.page-about .ab-switch {
  display: flex;
  margin-bottom: clamp(28px, 4vw, 48px);
}

/* ---------- 面板 ---------- */
.page-about .og-panel {
  display: none;
}

.page-about .og-panel.is-active {
  display: block;
}

.page-about .ab-line-wrap {
  padding-top: 8px;
  padding-bottom: var(--ab-gap);
}

/* ---------- 时间线导语 + 竖图 ---------- */
.page-about .ab-line-intro {
  display: grid;
  gap: 28px;
  margin-bottom: clamp(40px, 6vw, 76px);
}

.page-about .ab-line-intro__text p {
  margin: 16px 0 0;
  max-width: 36em;
  line-height: 1.78;
  color: var(--graphite);
}

.page-about .ab-line-intro__fig {
  max-width: 340px;
}

@media (min-width: 900px) {
  .page-about .ab-line-intro {
    grid-template-columns: minmax(0, 1fr) 320px;
    gap: clamp(32px, 5vw, 64px);
    align-items: start;
  }

  .page-about .ab-line-intro__fig {
    margin: 0;
  }
}

/* ---------- 图片 ---------- */
.page-about .ab-fig {
  margin: 0;
}

.page-about .ab-fig__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  background: var(--paper-lift);
}

.page-about .ab-fig__cap {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--graphite);
}

/* ---------- 时间线 ---------- */
.page-about .ab-line {
  position: relative;
}

.page-about .ab-line::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 12px;
  bottom: 12px;
  width: 2px;
  background: repeating-linear-gradient(
    to bottom,
    var(--mist) 0 5px,
    transparent 5px 13px
  );
}

.page-about .ab-node {
  position: relative;
  display: grid;
  gap: 8px;
  padding-left: 34px;
  padding-bottom: clamp(40px, 6vw, 68px);
}

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

.page-about .ab-node::before {
  content: "";
  position: absolute;
  left: 0;
  top: 5px;
  width: 14px;
  height: 14px;
  background: var(--ab-node-accent);
}

.page-about .ab-node--1 { --ab-node-accent: var(--mist); }
.page-about .ab-node--2 { --ab-node-accent: var(--graphite); }
.page-about .ab-node--3 { --ab-node-accent: var(--ember); }
.page-about .ab-node--4 { --ab-node-accent: var(--signal); }

.page-about .ab-node__ver {
  margin: 0;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--graphite);
}

.page-about .ab-node__body h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(20px, 2.8vw, 26px);
  line-height: 1.28;
}

.page-about .ab-node__body p {
  margin: 0 0 10px;
  max-width: 36em;
  line-height: 1.78;
}

.page-about .ab-node__key {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--graphite);
}

.page-about .ab-node__key::before {
  content: "// ";
  color: var(--ember);
}

@media (min-width: 768px) {
  .page-about .ab-node {
    grid-template-columns: 148px minmax(0, 1fr);
    column-gap: 30px;
    padding-left: 40px;
    padding-bottom: clamp(56px, 7vw, 92px);
  }

  .page-about .ab-node__ver {
    position: sticky;
    top: var(--sticky-top);
    align-self: start;
    padding-top: 6px;
  }
}

/* ---------- 章节收尾斜线 ---------- */
.page-about .ab-endmark {
  display: block;
  width: 68px;
  height: 3px;
  margin-top: clamp(28px, 4vw, 44px);
  background: var(--ember);
  transform: rotate(-8deg);
  transform-origin: left center;
}

/* ---------- 变更记录 ---------- */
.page-about .ab-log__lede {
  margin: 16px 0 0;
  max-width: 40em;
  line-height: 1.78;
  color: var(--graphite);
}

.page-about .ab-log {
  margin-top: 30px;
  background: var(--paper-lift);
  box-shadow: inset 0 0 0 1px var(--mist);
  clip-path: polygon(
    0 0,
    calc(100% - var(--notch)) 0,
    100% var(--notch),
    100% 100%,
    0 100%
  );
}

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

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

.page-about .ab-log__row {
  display: grid;
  gap: 6px;
  padding: 16px 18px;
  border-top: 1px solid var(--mist);
}

.page-about .ab-log__list .ab-log__row:first-child {
  border-top: 0;
}

.page-about .ab-log__ver {
  font-size: 14px;
  font-weight: 500;
  color: var(--ember);
  letter-spacing: 0.04em;
}

.page-about .ab-log__scope {
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink);
}

.page-about .ab-log__ref {
  font-size: 13px;
  color: var(--graphite);
  letter-spacing: 0.03em;
}

@media (min-width: 768px) {
  .page-about .ab-log__head {
    display: grid;
    grid-template-columns: 110px minmax(0, 1fr) 160px;
    gap: 22px;
    padding: 13px 22px;
    background: var(--ink);
    color: var(--paper);
    font-size: 12px;
    letter-spacing: 0.12em;
  }

  .page-about .ab-log__row {
    grid-template-columns: 110px minmax(0, 1fr) 160px;
    gap: 22px;
    align-items: baseline;
    padding: 16px 22px;
  }

  .page-about .ab-log__ref {
    text-align: right;
  }
}

.page-about .ab-log__fig {
  margin-top: clamp(28px, 4vw, 44px);
}

/* ---------- 老入口对照 ---------- */
.page-about .ab-compare {
  padding: clamp(40px, 6vw, 84px) 0;
}

.page-about .ab-compare__lede {
  margin: 16px 0 0;
  max-width: 40em;
  line-height: 1.78;
  color: var(--graphite);
}

.page-about .ab-map {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.page-about .ab-map__row {
  display: grid;
  gap: 8px;
  padding: 18px 0;
  border-top: 1px solid var(--mist);
}

.page-about .ab-map__row:last-child {
  border-bottom: 1px solid var(--mist);
}

.page-about .ab-map__old {
  font-size: 15px;
  line-height: 1.7;
  color: var(--graphite);
}

.page-about .ab-map__rule {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--ember);
  transform: rotate(-9deg);
}

.page-about .ab-map__new {
  font-size: 16px;
  font-weight: 500;
  line-height: 1.7;
  color: var(--ink);
}

@media (min-width: 768px) {
  .page-about .ab-map__row {
    grid-template-columns: minmax(0, 1fr) 56px minmax(0, 1fr);
    align-items: center;
    gap: 0;
    padding: 20px 0;
  }

  .page-about .ab-map__rule {
    width: 2px;
    height: 32px;
    margin: 0 auto;
    transform: rotate(9deg);
  }
}

.page-about .ab-compare__fig {
  margin-top: clamp(28px, 4vw, 48px);
}

/* ---------- 编号规则 ---------- */
.page-about .ab-rules {
  padding: clamp(40px, 6vw, 84px) 0;
}

.page-about .ab-rules__list {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 26px;
}

.page-about .ab-rules__item {
  display: grid;
  gap: 9px;
  align-content: start;
  padding-top: 14px;
  border-top: 3px solid var(--ink);
}

.page-about .ab-rules__key {
  font-size: 13px;
  letter-spacing: 0.05em;
  color: var(--ember);
}

.page-about .ab-rules__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(18px, 2.4vw, 22px);
  line-height: 1.3;
}

.page-about .ab-rules__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--graphite);
}

@media (min-width: 760px) {
  .page-about .ab-rules__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 30px;
  }
}

/* ---------- 维护说明 ---------- */
.page-about .ab-team {
  background: var(--arena);
  color: var(--paper);
  clip-path: polygon(
    0 0,
    100% 0,
    100% calc(100% - 26px),
    calc(100% - 26px) 100%,
    0 100%
  );
}

.page-about .ab-team__inner {
  display: grid;
  gap: 34px;
  padding-top: clamp(40px, 6vw, 76px);
  padding-bottom: clamp(44px, 6vw, 80px);
}

.page-about .ab-team__panel .og-section-head__num {
  color: var(--volt);
}

.page-about .ab-team__panel .og-section-head__title {
  color: var(--paper);
}

.page-about .ab-team__panel .og-section-head__rule {
  background: rgba(243, 238, 226, 0.32);
}

.page-about .ab-team__panel p {
  margin: 16px 0 0;
  max-width: 38em;
  line-height: 1.78;
  color: rgba(243, 238, 226, 0.84);
}

.page-about .ab-team__stats {
  display: grid;
  gap: 16px;
  align-content: start;
}

.page-about .ab-stat {
  display: grid;
  gap: 3px;
  padding-bottom: 13px;
  border-bottom: 1px solid rgba(243, 238, 226, 0.16);
}

.page-about .ab-stat__num {
  font-size: clamp(28px, 4.6vw, 40px);
  line-height: 1.1;
  font-weight: 500;
  color: var(--volt);
}

.page-about .ab-stat__label {
  font-size: 13px;
  letter-spacing: 0.03em;
  color: rgba(243, 238, 226, 0.7);
}

@media (min-width: 900px) {
  .page-about .ab-team__inner {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.85fr);
    gap: clamp(40px, 6vw, 88px);
  }
}

/* ---------- 后续入口 ---------- */
.page-about .ab-next {
  padding: clamp(40px, 6vw, 84px) 0 clamp(48px, 7vw, 96px);
}

.page-about .ab-next__list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
}

.page-about .ab-next__item {
  border-top: 1px solid var(--mist);
}

.page-about .ab-next__item:last-child {
  border-bottom: 1px solid var(--mist);
}

.page-about .ab-next__link {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 17px 0;
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink);
  text-decoration: none;
  transition: color 120ms var(--ease), transform 120ms var(--ease);
}

.page-about .ab-next__link:hover,
.page-about .ab-next__link:focus-visible {
  color: var(--ember);
  transform: translateX(6px);
}

.page-about .ab-next__num {
  flex: none;
  min-width: 18px;
  font-size: 13px;
  color: var(--ember);
}

/* ---------- 无障碍与动效降级 ---------- */
.page-about a:focus-visible,
.page-about button:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 3px;
}

.page-about .ab-hero a:focus-visible,
.page-about .ab-team a:focus-visible {
  outline: 2px solid var(--volt);
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-next__link,
  .page-about .og-reveal {
    transition: none !important;
    transform: none !important;
  }
}