.page-about {
  --ab-line: rgba(147, 169, 158, 0.26);
  --ab-line-strong: rgba(147, 169, 158, 0.46);
  --ab-pad: clamp(18px, 3.4vw, 40px);
  background: var(--by-ink);
  color: var(--by-paper);
  overflow-x: hidden;
}

.page-about img {
  max-width: 100%;
  height: auto;
}

/* ---------- 章节小地图 ---------- */
.page-about .ab-map {
  display: none;
}

.page-about .ab-map__label {
  margin: 0 0 10px;
  font-family: var(--by-font-mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--by-mist);
}

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

.page-about .ab-map__list a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  text-decoration: none;
  color: var(--by-mist);
  transition: color 0.25s var(--by-ease);
}

.page-about .ab-map__num {
  font-family: var(--by-font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  color: var(--by-lime);
}

.page-about .ab-map__name {
  font-size: 12px;
  letter-spacing: 0.08em;
}

.page-about .ab-map__list a:hover,
.page-about .ab-map__list a:focus-visible {
  color: var(--by-paper);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  isolation: isolate;
  border-bottom: 1px solid var(--ab-line);
  overflow: hidden;
}

.page-about .ab-hero__media {
  position: absolute;
  inset: 0;
  z-index: -1;
}

.page-about .ab-hero__media img {
  width: 100%;
  height: 100%;
  max-width: none;
  object-fit: cover;
  opacity: 0.5;
}

.page-about .ab-hero__media::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(6, 30, 23, 0.96) 0%, rgba(6, 30, 23, 0.8) 48%, rgba(6, 30, 23, 0.24) 100%),
    linear-gradient(0deg, rgba(6, 30, 23, 0.9) 0%, rgba(6, 30, 23, 0) 62%);
}

.page-about .ab-hero__inner {
  position: relative;
  padding-block: clamp(56px, 12vw, 132px);
}

.page-about .ab-hero .by-crumbs {
  margin-bottom: clamp(28px, 6vw, 56px);
}

.page-about .ab-hero .by-title {
  margin: 0;
  line-height: 0.94;
  letter-spacing: -0.02em;
  max-width: 14ch;
}

.page-about .ab-hero .by-lead {
  margin-top: clamp(20px, 3vw, 32px);
  max-width: 56ch;
  font-size: clamp(15px, 1.6vw, 18px);
  line-height: 1.85;
  color: var(--by-pale);
}

.page-about .ab-hero__facts {
  margin: clamp(32px, 6vw, 56px) 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--ab-line);
  border: 1px solid var(--ab-line);
  max-width: 640px;
}

.page-about .ab-fact {
  background: rgba(6, 30, 23, 0.82);
  padding: 14px 12px 16px;
  display: grid;
  gap: 4px;
}

.page-about .ab-fact__num {
  font-family: var(--by-font-mono);
  font-size: clamp(18px, 4.4vw, 26px);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--by-lime);
}

.page-about .ab-fact__label {
  font-size: 11px;
  line-height: 1.5;
  color: var(--by-mist);
}

/* ---------- 章节公用 ---------- */
.page-about .ab-chapter {
  border-bottom: 1px solid var(--ab-line);
}

.page-about .ab-intro {
  margin: 0 0 clamp(26px, 4.5vw, 46px);
  max-width: 62ch;
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.85;
  color: var(--by-pale);
}

.page-about .ab-sub {
  margin: 0 0 10px;
  font-size: clamp(16px, 1.8vw, 19px);
  line-height: 1.4;
  color: var(--by-paper);
}

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

.page-about .ab-note {
  margin: 24px 0 0;
  padding: 16px 18px;
  border-left: 2px solid var(--by-orange);
  background: rgba(255, 108, 47, 0.07);
  font-size: 14px;
  line-height: 1.8;
  color: var(--by-pale);
}

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

.page-about .ab-tl::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 10px;
  bottom: 18px;
  width: 1px;
  background: var(--ab-line-strong);
}

.page-about .ab-tl__item {
  position: relative;
  padding-left: 40px;
  padding-bottom: clamp(28px, 4.4vw, 46px);
}

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

.page-about .ab-tl__item::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 6px;
  width: 13px;
  height: 13px;
  background: var(--by-ink);
  border: 1px solid var(--by-lime);
  transition: background 0.25s var(--by-ease);
}

.page-about .ab-tl__item:hover::before,
.page-about .ab-tl__item:focus-within::before {
  background: var(--by-lime);
}

.page-about .ab-tl__year {
  display: block;
  font-family: var(--by-font-mono);
  font-size: clamp(19px, 3.4vw, 24px);
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--by-lime);
  margin-bottom: 6px;
}

.page-about .ab-tl__body {
  position: relative;
  max-width: 62ch;
}

.page-about .ab-tl__title {
  margin: 0;
  font-size: clamp(17px, 2.2vw, 22px);
  line-height: 1.35;
  color: var(--by-paper);
}

.page-about .ab-tl__stage {
  display: inline-block;
  margin-top: 8px;
  padding: 2px 8px;
  font-family: var(--by-font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: var(--by-ink);
  background: var(--by-mist);
  transition: background 0.25s var(--by-ease), color 0.25s var(--by-ease);
}

.page-about .ab-tl__item:hover .ab-tl__stage {
  background: var(--by-lime);
  color: var(--by-ink);
}

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

/* ---------- 采编流程 ---------- */
.page-about .ab-cai {
  align-items: start;
}

.page-about .ab-flow {
  border: 1px solid var(--ab-line);
  display: grid;
  gap: 1px;
  background: var(--ab-line);
}

.page-about .ab-flow__step {
  background: var(--by-ink-2);
  position: relative;
}

.page-about .ab-flow__step::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 0;
  height: 2px;
  background: var(--by-lime);
  transition: width 0.35s var(--by-ease);
}

.page-about .ab-flow__step[data-open]::before,
.page-about .ab-flow__step:hover::before {
  width: 100%;
}

.page-about .ab-flow__head {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 18px;
  background: none;
  border: 0;
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.page-about .ab-flow__num {
  font-family: var(--by-font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--by-lime);
  flex: none;
}

.page-about .ab-flow__title {
  flex: 1;
  font-size: clamp(16px, 2vw, 19px);
  font-weight: 700;
  letter-spacing: 0.01em;
}

.page-about .ab-flow__sign {
  font-family: var(--by-font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--by-orange);
  transition: transform 0.25s var(--by-ease);
}

.page-about .ab-flow__step[data-open] .ab-flow__sign {
  transform: rotate(45deg);
}

.page-about .ab-flow__panel {
  padding: 0 18px 18px 45px;
}

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

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

.page-about .ab-cai__figure .by-media {
  border: 1px solid var(--ab-line);
}

/* ---------- 合作网络 ---------- */
.page-about .ab-net {
  position: relative;
  border: 1px solid var(--ab-line);
  overflow: hidden;
}

.page-about .ab-net__img {
  display: block;
  width: 100%;
  max-width: none;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  opacity: 0.7;
}

.page-about .ab-net__node {
  position: absolute;
  width: 12px;
  height: 12px;
  transform: translate(-50%, -50%);
  background: var(--by-ink);
  border: 1px solid var(--by-lime);
  cursor: help;
  outline: none;
}

.page-about .ab-net__node::after {
  content: "";
  position: absolute;
  inset: -7px;
  border: 1px solid rgba(199, 255, 63, 0.28);
  opacity: 0;
  transition: opacity 0.25s var(--by-ease);
}

.page-about .ab-net__node:nth-of-type(1) { left: 18%; top: 28%; }
.page-about .ab-net__node:nth-of-type(2) { left: 44%; top: 52%; }
.page-about .ab-net__node:nth-of-type(3) { left: 68%; top: 24%; }
.page-about .ab-net__node:nth-of-type(4) { left: 26%; top: 72%; }
.page-about .ab-net__node:nth-of-type(5) { left: 80%; top: 66%; }

.page-about .ab-net__node:hover::after,
.page-about .ab-net__node:focus-visible::after {
  opacity: 1;
}

.page-about .ab-net__tag {
  position: absolute;
  left: 20px;
  top: 50%;
  transform: translateY(-50%);
  white-space: nowrap;
  padding: 3px 8px;
  background: var(--by-lime);
  color: var(--by-ink);
  font-family: var(--by-font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s var(--by-ease);
}

.page-about .ab-net__node:hover .ab-net__tag,
.page-about .ab-net__node:focus-visible .ab-net__tag {
  opacity: 1;
}

.page-about .ab-net__legend {
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 8px;
}

.page-about .ab-net__legend li {
  padding: 4px 9px;
  border: 1px solid var(--ab-line-strong);
  font-family: var(--by-font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--by-pale);
}

.page-about .ab-net__facts {
  margin-top: clamp(28px, 4vw, 44px);
  row-gap: 26px;
}

/* ---------- 品牌色 ---------- */
.page-about .ab-swatches {
  display: grid;
  gap: 1px;
  background: var(--ab-line);
  border: 1px solid var(--ab-line);
}

.page-about .ab-swatch {
  padding: 22px 20px 26px;
  display: grid;
  gap: 10px;
  align-content: start;
}

.page-about .ab-swatch--ink {
  background: #04140F;
  border-left: 3px solid #061E17;
}

.page-about .ab-swatch--paper {
  background: var(--by-paper);
  color: var(--by-line);
}

.page-about .ab-swatch--lime {
  background: var(--by-lime);
  color: var(--by-ink);
}

.page-about .ab-swatch--orange {
  background: var(--by-orange);
  color: var(--by-ink);
}

.page-about .ab-swatch__chip {
  display: block;
  width: 34px;
  height: 4px;
  background: currentColor;
  opacity: 0.65;
}

.page-about .ab-swatch--ink .ab-swatch__chip {
  color: var(--by-lime);
  opacity: 1;
}

.page-about .ab-swatch__name {
  margin: 0;
  font-size: clamp(17px, 2vw, 21px);
  letter-spacing: 0.02em;
}

.page-about .ab-swatch__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  opacity: 0.86;
}

.page-about .ab-swatch--ink .ab-swatch__text {
  color: var(--by-pale);
  opacity: 1;
}

/* ---------- 使用场景 ---------- */
.page-about .ab-scenes {
  display: grid;
  gap: 16px;
}

.page-about .ab-scene {
  display: grid;
  gap: 10px;
  align-content: start;
  padding: clamp(20px, 3vw, 28px);
}

.page-about .ab-scene .by-tag {
  justify-self: start;
}

.page-about .ab-scene__title {
  margin: 0;
  font-size: clamp(17px, 2.1vw, 21px);
  line-height: 1.35;
  color: var(--by-paper);
}

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

.page-about .ab-scene__link {
  justify-self: start;
  margin-top: 4px;
  font-family: var(--by-font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--by-lime);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s var(--by-ease);
}

.page-about .ab-scene__link:hover,
.page-about .ab-scene__link:focus-visible {
  border-bottom-color: var(--by-lime);
}

/* ---------- 结尾 ---------- */
.page-about .ab-cta {
  background: var(--by-ink-2);
  border-top: 2px solid var(--by-lime);
  padding-block: clamp(48px, 8vw, 96px);
}

.page-about .ab-cta__inner {
  display: grid;
  gap: clamp(26px, 4vw, 44px);
}

.page-about .ab-cta__title {
  margin: 12px 0 0;
  font-size: clamp(24px, 4.2vw, 40px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--by-paper);
}

.page-about .ab-cta__lede {
  margin: 16px 0 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--by-pale);
}

.page-about .ab-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-content: start;
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .ab-swatches {
    grid-template-columns: repeat(2, 1fr);
  }
  .page-about .ab-scenes {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 860px) {
  .page-about .ab-tl::before {
    left: 129px;
  }
  .page-about .ab-tl__item {
    display: grid;
    grid-template-columns: 108px minmax(0, 1fr);
    gap: 0 56px;
    padding-left: 0;
  }
  .page-about .ab-tl__item::before {
    left: 123px;
    top: 8px;
  }
  .page-about .ab-tl__year {
    text-align: right;
    font-size: clamp(24px, 2.4vw, 32px);
    padding-top: 2px;
    margin-bottom: 0;
  }
  .page-about .ab-flow {
    grid-template-columns: repeat(3, 1fr);
  }
  .page-about .ab-flow__head {
    flex-wrap: wrap;
    align-items: flex-start;
  }
  .page-about .ab-flow__title {
    flex: none;
    width: 100%;
    order: 3;
  }
  .page-about .ab-flow__sign {
    order: 2;
  }
  .page-about .ab-flow__panel {
    padding-left: 18px;
  }
}

@media (min-width: 1000px) {
  .page-about .ab-swatches {
    grid-template-columns: repeat(4, 1fr);
  }
  .page-about .ab-cta__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
  }
  .page-about .ab-cta__links {
    justify-content: flex-end;
  }
}

@media (min-width: 1480px) {
  .page-about .ab-map {
    display: block;
    position: fixed;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 6;
    padding: 14px 16px;
    border: 1px solid var(--ab-line);
    background: rgba(6, 30, 23, 0.82);
  }
}

@media (max-width: 619px) {
  .page-about .ab-hero__facts {
    grid-template-columns: 1fr;
  }
  .page-about .ab-fact {
    display: flex;
    align-items: baseline;
    gap: 12px;
    padding: 12px 14px;
  }
  .page-about .ab-fact__num {
    font-size: 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-flow__step::before,
  .page-about .ab-flow__sign,
  .page-about .ab-tl__item::before,
  .page-about .ab-tl__stage,
  .page-about .ab-net__node::after,
  .page-about .ab-net__tag,
  .page-about .ab-map__list a,
  .page-about .ab-scene__link {
    transition: none;
  }
}