.page-about {
  --ab-line: rgba(195, 154, 78, 0.30);
  --ab-line-soft: rgba(195, 154, 78, 0.15);
  background: var(--kt-cream);
  color: var(--kt-ink);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  background-color: var(--kt-night);
  background-image:
    linear-gradient(to right, rgba(195, 154, 78, 0.10) 1px, transparent 1px),
    radial-gradient(120% 90% at 88% 0%, rgba(47, 123, 224, 0.20), transparent 62%);
  background-size: 72px 100%, 100% 100%;
  color: var(--kt-white);
  padding-block: 20px 52px;
  border-bottom: 2px solid var(--kt-flare);
}

.page-about .ab-hero .kt-breadcrumb,
.page-about .ab-hero .kt-breadcrumb ol,
.page-about .ab-hero .kt-breadcrumb a {
  color: rgba(244, 239, 230, 0.66);
}
.page-about .ab-hero .kt-breadcrumb a:hover,
.page-about .ab-hero .kt-breadcrumb a:focus-visible {
  color: var(--kt-copper);
}

.page-about .ab-hero__grid {
  display: grid;
  gap: 28px;
  margin-top: 26px;
}

.page-about .ab-hero__title {
  margin: 10px 0 0;
  font-size: clamp(34px, 9vw, 62px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  font-weight: 900;
  color: var(--kt-white);
}

.page-about .ab-hero__lead {
  margin-top: 16px;
  max-width: 54ch;
  color: rgba(244, 239, 230, 0.76);
}

.page-about .ab-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.page-about .ab-hero__figure {
  margin: 0;
  border: 1px solid var(--ab-line);
  background: var(--kt-layer);
}
.page-about .ab-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
}
.page-about .ab-hero__figure .kt-figure__cap {
  padding: 8px 10px;
  font-size: 12px;
  color: rgba(244, 239, 230, 0.62);
  border-top: 1px solid var(--ab-line-soft);
}

.page-about .ab-stats {
  list-style: none;
  margin: 34px 0 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--ab-line);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 14px;
}
.page-about .ab-stats__item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}
.page-about .ab-stats__n {
  font-family: var(--kt-font-num);
  font-size: 34px;
  line-height: 1;
  font-weight: 700;
  color: var(--kt-copper);
}
.page-about .ab-stats__l {
  font-size: 13px;
  color: rgba(244, 239, 230, 0.66);
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-chapter {
  padding-block: 42px;
  border-bottom: 1px solid var(--ab-line-soft);
}
.page-about .ab-chapter--last {
  border-bottom: 0;
  padding-bottom: 20px;
}

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

.page-about .ab-chapter__index {
  display: flex;
  align-items: center;
  gap: 10px;
}
.page-about .ab-chapter__no {
  font-family: var(--kt-font-num);
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--kt-clay);
}
.page-about .ab-chapter__tick {
  display: inline-block;
  width: 28px;
  height: 1px;
  background: var(--kt-copper);
}

.page-about .ab-chapter__body {
  min-width: 0;
}
.page-about .ab-chapter__body > .kt-h2 {
  margin: 0 0 12px;
  font-size: clamp(22px, 4.6vw, 32px);
  line-height: 1.25;
  letter-spacing: -0.01em;
  font-weight: 800;
  color: var(--kt-ink);
}

.page-about .ab-p {
  margin: 0 0 12px;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.78;
  color: rgba(20, 32, 46, 0.82);
}
.page-about .ab-p--tight {
  margin-top: 16px;
  font-size: 14px;
  color: rgba(20, 32, 46, 0.68);
}
.page-about .ab-p a {
  color: var(--kt-clay);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 图文两栏 ---------- */
.page-about .ab-split {
  display: grid;
  gap: 22px;
  margin-top: 20px;
}

.page-about .ab-figure {
  margin: 0;
  border: 1px solid var(--ab-line);
  background: var(--kt-white);
}
.page-about .ab-figure img {
  display: block;
  width: 100%;
  height: auto;
}
.page-about .ab-figure figcaption {
  padding: 9px 12px 10px;
  font-size: 12.5px;
  line-height: 1.6;
  color: rgba(20, 32, 46, 0.62);
  border-top: 1px solid var(--ab-line-soft);
}

/* ---------- 三段流程 ---------- */
.page-about .ab-steps {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}
.page-about .ab-step {
  padding: 13px 14px 15px;
  background: var(--kt-white);
  border: 1px solid var(--ab-line-soft);
  border-top: 2px solid var(--kt-copper);
  transition: border-color 160ms ease, transform 160ms ease;
}
.page-about .ab-step:hover {
  border-top-color: var(--kt-flare);
}
.page-about .ab-step__no {
  display: block;
  font-family: var(--kt-font-num);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--kt-clay);
}
.page-about .ab-step__name {
  margin: 6px 0 6px;
  font-size: 16px;
  font-weight: 700;
  color: var(--kt-ink);
}
.page-about .ab-step__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: rgba(20, 32, 46, 0.74);
}

/* ---------- 观察员四字段 ---------- */
.page-about .ab-fields {
  list-style: none;
  margin: 16px 0 4px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}
.page-about .ab-field {
  padding: 10px 11px 12px;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--ab-line-soft);
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}
.page-about .ab-field__k {
  font-family: var(--kt-font-num);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--kt-clay);
}
.page-about .ab-field__v {
  font-size: 13.5px;
  line-height: 1.6;
  color: rgba(20, 32, 46, 0.76);
}

/* ---------- 时间轴 ---------- */
.page-about .ab-timeline {
  position: relative;
  list-style: none;
  margin: 20px 0 0;
  padding: 0 0 0 18px;
}
.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 14px;
  bottom: 14px;
  width: 1px;
  background: var(--ab-line);
}
.page-about .ab-milestone {
  position: relative;
  padding: 11px 0 12px 8px;
  border-bottom: 1px solid var(--ab-line-soft);
  transition: background-color 160ms ease;
}
.page-about .ab-milestone:last-child {
  border-bottom: 0;
}
.page-about .ab-milestone::before {
  content: "";
  position: absolute;
  left: -22px;
  top: 20px;
  width: 8px;
  height: 8px;
  background: var(--kt-cream);
  border: 1px solid var(--kt-copper);
  transition: background-color 160ms ease, border-color 160ms ease;
}
.page-about .ab-milestone:hover::before,
.page-about .ab-milestone:focus-visible::before,
.page-about .ab-milestone:focus-within::before {
  background: var(--kt-flare);
  border-color: var(--kt-flare);
}
.page-about .ab-milestone:focus-visible {
  outline: 2px solid var(--kt-clay);
  outline-offset: 2px;
}
.page-about .ab-milestone__year {
  display: block;
  font-family: var(--kt-font-num);
  font-size: 22px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--kt-clay);
}
.page-about .ab-milestone__title {
  margin: 4px 0 4px;
  font-size: 15px;
  font-weight: 700;
  color: var(--kt-ink);
}
.page-about .ab-milestone__note {
  margin: 0;
  max-width: 58ch;
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(20, 32, 46, 0.7);
  transition: color 160ms ease;
}
.page-about .ab-milestone:hover .ab-milestone__note {
  color: rgba(20, 32, 46, 0.9);
}

/* ---------- 四条标准（分段切换） ---------- */
.page-about .ab-tabs {
  margin-top: 18px;
}
.page-about .ab-tabs__list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}
.page-about .ab-tab {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 3px;
  padding: 12px 12px 14px;
  text-align: left;
  cursor: pointer;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid var(--ab-line-soft);
  border-radius: var(--kt-r);
  color: var(--kt-ink);
  transition: border-color 160ms ease, background-color 160ms ease;
}
.page-about .ab-tab:hover {
  border-color: var(--kt-copper);
}
.page-about .ab-tab[aria-selected="true"] {
  background: var(--kt-white);
  border-color: var(--kt-flare);
  box-shadow: inset 0 0 0 1px var(--kt-flare);
}
.page-about .ab-tab:focus-visible {
  outline: 2px solid var(--kt-clay);
  outline-offset: 2px;
}
.page-about .ab-tab__num {
  font-family: var(--kt-font-num);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--kt-clay);
}
.page-about .ab-tab__name {
  font-size: 19px;
  font-weight: 800;
  line-height: 1.1;
  color: var(--kt-ink);
}
.page-about .ab-tab__hint {
  font-size: 12.5px;
  color: rgba(20, 32, 46, 0.62);
}

.page-about .ab-panel {
  margin-top: 12px;
  padding: 18px 16px 16px;
  background: var(--kt-white);
  border: 1px solid var(--ab-line-soft);
  border-left: 3px solid var(--kt-flare);
}
.page-about .ab-panel[hidden] {
  display: none;
}
.page-about .ab-panel__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  color: var(--kt-ink);
}
.page-about .ab-panel .ab-p {
  font-size: 15px;
  margin-bottom: 10px;
}
.page-about .ab-points {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 6px;
}
.page-about .ab-points li {
  position: relative;
  padding-left: 16px;
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(20, 32, 46, 0.74);
}
.page-about .ab-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 7px;
  height: 1px;
  background: var(--kt-copper);
}

/* ---------- 收尾斜切 ---------- */
.page-about .ab-outro {
  margin-top: 44px;
  padding-block: 92px 52px;
  background-color: var(--kt-night);
  background-image:
    linear-gradient(to right, rgba(195, 154, 78, 0.10) 1px, transparent 1px),
    radial-gradient(90% 120% at 10% 100%, rgba(255, 92, 26, 0.14), transparent 60%);
  background-size: 72px 100%, 100% 100%;
  color: var(--kt-white);
  clip-path: polygon(0 46px, 100% 0, 100% 100%, 0 100%);
}
.page-about .ab-outro__inner {
  display: grid;
  gap: 28px;
}
.page-about .ab-outro__title {
  margin: 10px 0 12px;
  font-size: clamp(24px, 5vw, 36px);
  line-height: 1.15;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--kt-white);
}
.page-about .ab-outro__lead {
  margin: 0;
  max-width: 48ch;
  font-size: 15.5px;
  line-height: 1.78;
  color: rgba(244, 239, 230, 0.76);
}
.page-about .ab-outro__side {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 14px;
  padding-top: 18px;
  border-top: 1px solid var(--ab-line);
}
.page-about .ab-outro__mail {
  margin: 0;
  font-family: var(--kt-font-num);
  font-size: 14px;
  line-height: 1.9;
  color: var(--kt-copper);
  word-break: break-all;
}
.page-about .ab-outro__mail span {
  display: inline-block;
  font-family: inherit;
  font-size: 12px;
  color: rgba(244, 239, 230, 0.6);
}
.page-about .ab-outro__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
}
.page-about .ab-outro__links a {
  font-size: 13.5px;
  color: rgba(244, 239, 230, 0.74);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 160ms ease, border-color 160ms ease;
}
.page-about .ab-outro__links a:hover,
.page-about .ab-outro__links a:focus-visible {
  color: var(--kt-white);
  border-bottom-color: var(--kt-copper);
}

/* ---------- 媒体查询 ---------- */
@media (min-width: 640px) {
  .page-about .ab-fields {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .ab-tabs__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .ab-hero {
    padding-block: 24px 64px;
  }
  .page-about .ab-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .ab-chapter {
    padding-block: 52px;
  }
  .page-about .ab-panel {
    padding: 22px 22px 20px;
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: start;
    gap: 40px;
  }
  .page-about .ab-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .ab-chapter__inner {
    grid-template-columns: 82px minmax(0, 1fr);
    gap: 30px;
  }
  .page-about .ab-chapter__index {
    flex-direction: column;
    align-items: flex-start;
    writing-mode: vertical-rl;
    gap: 14px;
    padding-top: 6px;
  }
  .page-about .ab-chapter__no {
    letter-spacing: 0.3em;
  }
  .page-about .ab-split {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    align-items: start;
    gap: 28px;
  }
  .page-about .ab-split--rev {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  }
  .page-about .ab-milestone {
    display: grid;
    grid-template-columns: 92px minmax(0, 1fr);
    gap: 16px;
    padding: 14px 0 15px;
  }
  .page-about .ab-milestone__year {
    font-size: 26px;
    text-align: right;
  }
  .page-about .ab-outro {
    padding-block: 108px 60px;
    clip-path: polygon(0 64px, 100% 0, 100% 100%, 0 100%);
  }
  .page-about .ab-outro__inner {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
    gap: 48px;
  }
  .page-about .ab-outro__side {
    border-top: 0;
    border-left: 1px solid var(--ab-line);
    padding-top: 0;
    padding-left: 24px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-step,
  .page-about .ab-milestone,
  .page-about .ab-milestone::before,
  .page-about .ab-milestone__note,
  .page-about .ab-tab,
  .page-about .ab-outro__links a {
    transition: none;
  }
}