.page-about {
  background: var(--paper);
  color: var(--char);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about .ab-wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: 20px;
}

.page-about .eyebrow {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--red);
  margin: 0 0 12px;
}

.page-about .ab-crumb {
  padding-top: 22px;
  padding-bottom: 14px;
}

.page-about .ab-crumb .breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: rgba(11, 19, 43, 0.6);
}

.page-about .ab-crumb .breadcrumbs a {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--hair);
  padding-bottom: 1px;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .ab-crumb .breadcrumbs a:hover,
.page-about .ab-crumb .breadcrumbs a:focus-visible {
  color: var(--red);
  border-color: var(--red);
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  position: relative;
  background: var(--ink);
  color: var(--white);
  overflow: hidden;
  box-shadow: 0 22px 44px -30px rgba(11, 19, 43, 0.9);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 12px;
  border: 1px solid var(--hair-light);
  pointer-events: none;
  z-index: 2;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 12px;
  background-image: repeating-linear-gradient(90deg, var(--amber) 0 2px, transparent 2px 26px);
  opacity: 0.62;
  pointer-events: none;
  z-index: 2;
}

.page-about .ab-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 30px;
  padding-block: 48px 44px;
}

.page-about .ab-hero .eyebrow {
  color: var(--amber);
  margin-bottom: 14px;
}

.page-about .ab-hero h1 {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(38px, 9vw, 70px);
  line-height: 1.02;
  letter-spacing: -0.02em;
  margin: 0 0 18px;
  color: var(--white);
}

.page-about .ab-hero h1::after {
  content: "";
  display: block;
  width: 98px;
  height: 6px;
  margin-top: 20px;
  background: linear-gradient(90deg, var(--red) 0 42%, var(--amber) 42% 100%);
}

.page-about .ab-hero__intro {
  max-width: 58ch;
  margin: 0 0 26px;
  font-size: 16px;
  line-height: 1.82;
  color: rgba(241, 250, 238, 0.86);
}

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

.page-about .ab-hero .btn--ghost {
  color: var(--white);
  border-color: rgba(241, 250, 238, 0.38);
}

.page-about .ab-hero .btn--ghost:hover,
.page-about .ab-hero .btn--ghost:focus-visible {
  color: var(--amber);
  border-color: var(--amber);
}

.page-about .ab-hero__meta {
  position: relative;
  padding: 20px 20px 16px;
  background: rgba(11, 19, 43, 0.55);
  border: 1px solid var(--hair-light);
}

.page-about .ab-hero__meta::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 46px;
  height: 4px;
  background: var(--red);
}

.page-about .ab-hero__metatitle {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .ab-hero__dlist {
  margin: 0;
}

.page-about .ab-hero__row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 14px;
  padding: 9px 0;
  border-bottom: 1px dashed var(--hair-light);
}

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

.page-about .ab-hero__row dt {
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: rgba(241, 250, 238, 0.62);
}

.page-about .ab-hero__row dd {
  margin: 0;
  font-size: 14px;
  font-weight: 600;
  text-align: right;
  color: var(--white);
}

/* ---------- 数据横切面 ---------- */

.page-about .ab-strip {
  padding-block: 34px;
  background: var(--paper);
  border-bottom: 1px solid var(--hair);
}

.page-about .ab-strip__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
}

.page-about .ab-strip__cell {
  background: var(--paper);
  padding: 20px 16px 22px;
}

.page-about .ab-strip__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(24px, 5.4vw, 34px);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.02em;
}

.page-about .ab-strip__cell:nth-child(1) .ab-strip__num {
  color: var(--red);
}

.page-about .ab-strip__cell:nth-child(2) .ab-strip__num {
  color: var(--amber-deep);
}

.page-about .ab-strip__cell:nth-child(3) .ab-strip__num {
  color: var(--ink);
}

.page-about .ab-strip__cell:nth-child(4) .ab-strip__num {
  color: var(--blue);
}

.page-about .ab-strip__label {
  display: block;
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.6;
  color: rgba(11, 19, 43, 0.64);
}

/* ---------- 通用章节 ---------- */

.page-about .ab-section {
  padding-block: 56px;
}

.page-about .ab-head {
  max-width: 64ch;
  margin-bottom: 32px;
}

.page-about .ab-head h2 {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(26px, 4.6vw, 40px);
  line-height: 1.14;
  letter-spacing: -0.015em;
  margin: 0 0 14px;
  color: var(--char);
}

.page-about .ab-head p {
  margin: 0;
  font-size: 16.5px;
  line-height: 1.8;
  color: rgba(11, 19, 43, 0.72);
}

/* ---------- 看台视角 ---------- */

.page-about .ab-lead__grid {
  display: grid;
  gap: 22px;
}

.page-about .ab-lead__head h2 {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(26px, 4.6vw, 38px);
  line-height: 1.16;
  letter-spacing: -0.015em;
  margin: 0;
  color: var(--char);
}

.page-about .ab-lead__body p {
  margin: 0 0 18px;
  font-size: 16.5px;
  line-height: 1.85;
  color: rgba(11, 19, 43, 0.8);
}

.page-about .ab-facts {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .ab-facts li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 12px;
  align-items: start;
  padding: 14px 16px;
  background: var(--white);
  border: 1px solid var(--hair);
  border-left: 3px solid var(--amber);
  font-size: 15px;
  line-height: 1.7;
  color: rgba(11, 19, 43, 0.82);
}

.page-about .ab-facts li:nth-child(1) {
  border-left-color: var(--red);
}

.page-about .ab-facts li:nth-child(2) {
  border-left-color: var(--blue);
}

/* ---------- 数据运营中心 ---------- */

.page-about .ab-ops__grid {
  display: grid;
  gap: 30px;
}

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

.page-about .ab-ops__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--hair-strong);
  filter: saturate(0.92) contrast(1.03);
}

.page-about .ab-ops__figure::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 34px;
  width: 58px;
  height: 58px;
  border-left: 4px solid var(--red);
  border-bottom: 4px solid var(--red);
  pointer-events: none;
}

.page-about .ab-ops__figure figcaption {
  margin-top: 14px;
  font-size: 13px;
  line-height: 1.65;
  color: rgba(11, 19, 43, 0.6);
}

.page-about .ab-ops__body h2 {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(24px, 4.2vw, 36px);
  line-height: 1.16;
  letter-spacing: -0.015em;
  margin: 0 0 14px;
  color: var(--char);
}

.page-about .ab-ops__text {
  margin: 0;
  font-size: 16px;
  line-height: 1.82;
  color: rgba(11, 19, 43, 0.78);
}

.page-about .ab-flow {
  list-style: none;
  counter-reset: abflow;
  margin: 26px 0 0;
  padding: 0;
}

.page-about .ab-flow li {
  counter-increment: abflow;
  position: relative;
  padding: 15px 0 15px 46px;
  border-top: 1px dashed var(--hair);
  font-size: 15px;
  line-height: 1.72;
  color: rgba(11, 19, 43, 0.8);
}

.page-about .ab-flow li:last-child {
  border-bottom: 1px dashed var(--hair);
}

.page-about .ab-flow li::before {
  content: counter(abflow, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 16px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--red);
}

.page-about .ab-flow strong {
  color: var(--char);
  font-weight: 700;
}

/* ---------- 版本时间线 ---------- */

.page-about .ab-versions__figure {
  margin: 0 0 40px;
  padding: 10px;
  background: var(--white);
  border: 1px solid var(--hair);
}

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

.page-about .ab-versions__figure figcaption {
  padding: 12px 4px 2px;
  font-size: 13px;
  line-height: 1.65;
  color: rgba(11, 19, 43, 0.6);
}

.page-about .ab-tl {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-tl__item {
  position: relative;
  display: grid;
  gap: 16px;
  padding-bottom: 34px;
}

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

.page-about .ab-tl__node {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  width: 56px;
  height: 56px;
  font-family: var(--font-mono);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--white);
  background: var(--ink);
  border: 1px solid var(--char);
  box-shadow: 3px 3px 0 rgba(11, 19, 43, 0.14);
}

.page-about .ab-tl__node[data-tone="amber"] {
  background: var(--amber);
  border-color: var(--amber-deep);
  color: var(--char);
}

.page-about .ab-tl__node[data-tone="blue"] {
  background: var(--blue);
  border-color: var(--ink);
}

.page-about .ab-tl__node[data-tone="red"] {
  background: var(--red);
  border-color: var(--red-deep);
}

.page-about .ab-tl__card {
  position: relative;
  padding: 22px 20px 20px;
  background: var(--white);
  border: 1px solid var(--hair-strong);
  border-top: 3px solid var(--char);
  box-shadow: 6px 6px 0 rgba(11, 19, 43, 0.07);
}

.page-about .ab-tl__item[data-tone="amber"] .ab-tl__card {
  border-top-color: var(--amber);
}

.page-about .ab-tl__item[data-tone="blue"] .ab-tl__card {
  border-top-color: var(--blue);
}

.page-about .ab-tl__item[data-tone="red"] .ab-tl__card {
  border-top-color: var(--red);
}

.page-about .ab-tl__stage {
  display: inline-block;
  margin-bottom: 12px;
  padding: 4px 9px;
  background: var(--char);
  color: var(--white);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.page-about .ab-tl__card h3 {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(20px, 3.2vw, 26px);
  line-height: 1.22;
  color: var(--char);
}

.page-about .ab-tl__card > p {
  margin: 0 0 14px;
  font-size: 15.5px;
  line-height: 1.78;
  color: rgba(11, 19, 43, 0.78);
}

.page-about .ab-tl__points {
  list-style: none;
  margin: 0 0 16px;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .ab-tl__points li {
  position: relative;
  padding-left: 18px;
  font-size: 14.5px;
  line-height: 1.7;
  color: rgba(11, 19, 43, 0.78);
}

.page-about .ab-tl__points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 8px;
  height: 8px;
  background: var(--amber);
}

.page-about .ab-tl__item[data-tone="blue"] .ab-tl__points li::before {
  background: var(--blue);
}

.page-about .ab-tl__item[data-tone="red"] .ab-tl__points li::before {
  background: var(--red);
}

.page-about .ab-tl__card .accordion__btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: 100%;
  padding: 12px 0 0;
  background: none;
  border: 0;
  border-top: 1px dashed var(--hair);
  font-family: var(--font-body);
  font-size: 13.5px;
  font-weight: 600;
  color: var(--ink);
  text-align: left;
  cursor: pointer;
  transition: color 0.18s ease;
}

.page-about .ab-tl__card .accordion__btn:hover,
.page-about .ab-tl__card .accordion__btn:focus-visible {
  color: var(--red);
}

.page-about .ab-tl__card .accordion__panel p {
  margin: 12px 0 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: rgba(11, 19, 43, 0.72);
}

/* ---------- 覆盖与合作 ---------- */

.page-about .ab-reach__top {
  display: grid;
  gap: 26px;
  margin-bottom: 38px;
}

.page-about .ab-reach__figure {
  margin: 0;
  padding: 10px;
  background: var(--ink);
  border: 1px solid var(--char);
}

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

.page-about .ab-reach__figure figcaption {
  padding: 12px 4px 2px;
  font-size: 12.5px;
  line-height: 1.6;
  color: rgba(241, 250, 238, 0.7);
}

.page-about .ab-tabs .tabs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin-bottom: 26px;
  border-bottom: 2px solid var(--char);
}

.page-about .ab-tabs .tabs__tab {
  margin-right: -1px;
  margin-bottom: -2px;
  padding: 12px 16px;
  background: transparent;
  border: 1px solid var(--hair-strong);
  border-bottom: 2px solid var(--char);
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: rgba(11, 19, 43, 0.68);
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.page-about .ab-tabs .tabs__tab:hover,
.page-about .ab-tabs .tabs__tab:focus-visible {
  color: var(--red);
  border-color: var(--red);
  border-bottom-color: var(--char);
}

.page-about .ab-tabs .tabs__tab[aria-selected="true"] {
  background: var(--char);
  border-color: var(--char);
  border-bottom-color: var(--char);
  color: var(--white);
}

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

.page-about .ab-card {
  position: relative;
  padding: 20px 18px 22px;
  background: var(--white);
  border: 1px solid var(--hair);
  transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
}

.page-about .ab-card:hover,
.page-about .ab-card:focus-within {
  transform: translateY(-4px);
  border-color: var(--amber);
  box-shadow: 0 16px 28px -20px rgba(11, 19, 43, 0.6);
}

.page-about .ab-card__type {
  display: inline-block;
  margin-bottom: 12px;
  padding: 3px 8px;
  background: var(--mist);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  transition: background 0.2s ease, color 0.2s ease;
}

.page-about .ab-card:hover .ab-card__type {
  background: var(--ink);
  color: var(--white);
}

.page-about .ab-card h4 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 800;
  line-height: 1.35;
  color: var(--char);
}

.page-about .ab-card p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(11, 19, 43, 0.75);
}

/* ---------- 同步节奏 ---------- */

.page-about .ab-cadence {
  position: relative;
  background: var(--ink);
  color: var(--white);
  overflow: hidden;
}

.page-about .ab-cadence::before {
  content: "";
  position: absolute;
  inset: 14px;
  border: 1px solid var(--hair-light);
  pointer-events: none;
}

.page-about .ab-cadence > .ab-wrap {
  position: relative;
  z-index: 1;
}

.page-about .ab-cadence .eyebrow {
  color: var(--amber);
}

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

.page-about .ab-cadence .ab-head p {
  color: rgba(241, 250, 238, 0.76);
}

.page-about .ab-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--hair-light);
  border: 1px solid var(--hair-light);
}

.page-about .ab-steps li {
  padding: 24px 20px 26px;
  background: var(--ink);
}

.page-about .ab-steps__time {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--amber);
}

.page-about .ab-steps__time--red {
  color: var(--red);
}

.page-about .ab-steps__time--blue {
  color: var(--mist);
}

.page-about .ab-steps h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 800;
  color: var(--white);
}

.page-about .ab-steps p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(241, 250, 238, 0.76);
}

.page-about .ab-cadence__note {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  margin-top: 26px;
}

.page-about .ab-cadence__note p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.7;
  color: rgba(241, 250, 238, 0.82);
}

.page-about .ab-cadence__note .mono {
  color: var(--amber);
}

/* ---------- 继续浏览 ---------- */

.page-about .ab-next {
  padding-bottom: 72px;
}

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

.page-about .ab-next__card {
  position: relative;
  display: block;
  padding: 22px 20px 24px;
  background: var(--white);
  border: 1px solid var(--hair-strong);
  text-decoration: none;
  color: inherit;
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.page-about .ab-next__card::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: var(--red);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.24s ease;
}

.page-about .ab-next__card:hover,
.page-about .ab-next__card:focus-visible {
  transform: translateY(-4px);
  box-shadow: 0 18px 30px -22px rgba(11, 19, 43, 0.62);
}

.page-about .ab-next__card:hover::before,
.page-about .ab-next__card:focus-visible::before {
  transform: scaleY(1);
}

.page-about .ab-next__k {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--blue);
}

.page-about .ab-next__t {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-head);
  font-size: 19px;
  font-weight: 800;
  color: var(--char);
}

.page-about .ab-next__d {
  display: block;
  font-size: 14.5px;
  line-height: 1.72;
  color: rgba(11, 19, 43, 0.72);
}

/* ---------- 响应式 ---------- */

@media (min-width: 720px) {
  .page-about .ab-wrap {
    padding-inline: 34px;
  }

  .page-about .ab-hero__intro {
    font-size: 17px;
  }

  .page-about .ab-strip__cell {
    padding: 24px 20px 26px;
  }

  .page-about .ab-facts li {
    font-size: 15.5px;
  }

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

@media (min-width: 820px) {
  .page-about .ab-section {
    padding-block: 84px;
  }

  .page-about .ab-strip {
    padding-block: 38px;
  }

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

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

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

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(280px, 0.78fr);
    gap: 52px;
    align-items: end;
    padding-block: 76px 68px;
  }

  .page-about .ab-lead__grid {
    grid-template-columns: minmax(0, 0.82fr) minmax(0, 1.35fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .ab-ops__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.08fr);
    gap: 54px;
    align-items: center;
  }

  .page-about .ab-reach__top {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.02fr);
    gap: 48px;
    align-items: center;
  }

  .page-about .ab-tl__item {
    grid-template-columns: 108px minmax(0, 1fr);
    gap: 34px;
    padding-bottom: 44px;
  }

  .page-about .ab-tl::before {
    content: "";
    position: absolute;
    left: 27px;
    top: 12px;
    bottom: 12px;
    width: 2px;
    background: repeating-linear-gradient(180deg, var(--hair-strong) 0 6px, transparent 6px 13px);
  }

  .page-about .ab-versions__figure {
    margin-bottom: 48px;
  }
}

@media (min-width: 1100px) {
  .page-about .ab-hero__grid {
    padding-block: 88px 80px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-card,
  .page-about .ab-next__card,
  .page-about .ab-next__card::before,
  .page-about .ab-tabs .tabs__tab,
  .page-about .ab-tl__card .accordion__btn {
    transition: none !important;
  }

  .page-about .ab-card:hover,
  .page-about .ab-next__card:hover {
    transform: none;
  }
}