.page-about {
  --ab-hair: rgba(53, 242, 224, 0.18);
  display: block;
}

/* ---------- 面包屑下的进场留白 ---------- */
.page-about .ab-hero {
  padding-block: 30px 8px;
}

.page-about .ab-hero__frame {
  position: relative;
  padding: 26px 18px 30px;
  border-radius: var(--radius);
  background:
    linear-gradient(158deg, rgba(53, 242, 224, 0.09), rgba(53, 242, 224, 0) 46%),
    linear-gradient(22deg, rgba(138, 91, 255, 0.13), rgba(138, 91, 255, 0) 54%),
    var(--bg-2);
}

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

.page-about .ab-hero__main {
  min-width: 0;
}

.page-about .ab-hero h1 {
  margin: 14px 0 0;
  font-size: clamp(29px, 7.4vw, 56px);
  line-height: 1.1;
  letter-spacing: -0.03em;
  font-weight: 800;
  color: var(--text);
  text-wrap: balance;
}

.page-about .ab-hero__lead {
  margin: 18px 0 0;
  max-width: 58ch;
  font-size: 16.5px;
  line-height: 1.9;
  color: var(--muted);
}

/* 首屏数据条 */
.page-about .ab-meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 18px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.page-about .ab-meta__item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.page-about .ab-meta__num {
  font-family: var(--mono);
  font-size: 20px;
  line-height: 1.2;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

.page-about .ab-meta__label {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

/* ---------- 时间轴区块 ---------- */
.page-about .ab-track {
  padding-block: 48px 40px;
}

.page-about .ab-track__intro {
  margin: 16px 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .ab-media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-3);
}

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

.page-about .ab-media--hero {
  aspect-ratio: 1200 / 640;
  margin-top: 26px;
}

.page-about .ab-media--work {
  aspect-ratio: 1000 / 700;
}

.page-about .ab-media--map {
  aspect-ratio: 1200 / 760;
  margin-top: 26px;
}

/* 时间轴本体 */
.page-about .ab-tl {
  position: relative;
  margin: 32px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-tl::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 18px;
  width: 1px;
  background: linear-gradient(180deg, var(--line) 0%, var(--violet) 44%, var(--amber) 100%);
  opacity: 0.9;
}

.page-about .ab-tl__item {
  position: relative;
  padding-left: 34px;
  --accent: var(--cyan);
}

.page-about .ab-tl__item:nth-child(1) { padding-bottom: 22px; }
.page-about .ab-tl__item:nth-child(2) { padding-bottom: 28px; }
.page-about .ab-tl__item:nth-child(3) { padding-bottom: 34px; --accent: var(--violet); }
.page-about .ab-tl__item:nth-child(4) { padding-bottom: 42px; --accent: var(--amber); }
.page-about .ab-tl__item:nth-child(5) { padding-bottom: 0; --accent: var(--amber); }

.page-about .ab-tl__dot {
  position: absolute;
  left: 0;
  top: 6px;
  width: 15px;
  height: 15px;
  border: 1px solid var(--accent);
  border-radius: 50%;
  background: var(--bg);
  box-sizing: border-box;
}

.page-about .ab-tl__dot::after {
  content: "";
  position: absolute;
  inset: 3px;
  border-radius: 50%;
  background: var(--accent);
}

.page-about .ab-tl__item--now .ab-tl__dot::before {
  content: "";
  position: absolute;
  inset: -7px;
  border: 1px solid var(--accent);
  border-radius: 50%;
  animation: ab-pulse 2.6s var(--ease) infinite;
}

@keyframes ab-pulse {
  0%   { transform: scale(0.55); opacity: 0.85; }
  70%  { transform: scale(1.25); opacity: 0; }
  100% { transform: scale(1.25); opacity: 0; }
}

.page-about .ab-tl__card {
  position: relative;
  padding: 18px 16px 20px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--accent);
  border-radius: var(--radius);
  background: var(--bg-3);
  transition: border-color 0.24s var(--ease), box-shadow 0.24s var(--ease), transform 0.24s var(--ease);
}

.page-about .ab-tl__card:hover,
.page-about .ab-tl__card:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px rgba(53, 242, 224, 0.08), 0 0 26px -14px var(--accent);
  transform: translateY(-2px);
}

.page-about .ab-tl__tag {
  display: inline-block;
  padding: 3px 12px 3px 9px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--bg);
  background: var(--accent);
  clip-path: polygon(0 0, 100% 0, calc(100% - 9px) 100%, 0 100%);
}

.page-about .ab-tl__card h3 {
  margin: 12px 0 0;
  font-size: clamp(18px, 4.2vw, 22px);
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .ab-tl__card p {
  margin: 10px 0 0;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .ab-tl__more {
  margin-top: 12px;
  padding-top: 10px;
  border-top: 1px dashed var(--line);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.02em;
  color: var(--dim);
}

/* ---------- 横向宽幅节奏条 ---------- */
.page-about .ab-band {
  position: relative;
  margin: 18px 0 0;
  padding: 42px 0 46px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background:
    linear-gradient(102deg, rgba(138, 91, 255, 0.22), rgba(53, 242, 224, 0.1) 52%, rgba(5, 10, 36, 0) 88%),
    var(--bg-2);
}

.page-about .ab-band::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 4px;
  background: linear-gradient(180deg, var(--cyan), var(--violet) 52%, var(--amber));
}

.page-about .ab-band__intro {
  margin: 16px 0 0;
  max-width: 60ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .ab-phases {
  display: grid;
  gap: 16px;
  margin-top: 28px;
}

.page-about .ab-phase {
  position: relative;
  padding: 22px 18px 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(19, 28, 77, 0.72);
}

.page-about .ab-phase::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 34%;
  height: 3px;
  background: linear-gradient(90deg, var(--cyan), rgba(53, 242, 224, 0));
}

.page-about .ab-phase--sprint::before {
  background: linear-gradient(90deg, var(--amber), rgba(255, 166, 61, 0));
}

.page-about .ab-phase__idx {
  margin: 0;
  font-family: var(--mono);
  font-size: 30px;
  line-height: 1;
  letter-spacing: 0.06em;
  color: rgba(233, 237, 255, 0.16);
}

.page-about .ab-phase h3 {
  margin: 10px 0 0;
  font-size: 20px;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .ab-phase p {
  margin: 10px 0 0;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .ab-band__note {
  margin: 22px 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--amber);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 内容生态 ---------- */
.page-about .ab-eco {
  padding-block: 46px 8px;
}

.page-about .ab-split {
  display: grid;
  gap: 26px;
  align-items: start;
}

.page-about .ab-split__body p {
  margin: 16px 0 0;
  font-size: 16px;
  line-height: 1.88;
  color: var(--muted);
}

.page-about .ab-split__body a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 242, 224, 0.4);
  transition: border-color 0.2s var(--ease), color 0.2s var(--ease);
}

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

.page-about .ab-eco__facts {
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--line);
  overflow: hidden;
}

.page-about .ab-eco__facts li {
  display: grid;
  gap: 4px;
  padding: 14px 16px;
  background: var(--bg-2);
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .ab-eco__facts span {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

/* ---------- 服务覆盖 ---------- */
.page-about .ab-infra {
  padding-block: 46px 20px;
}

.page-about .ab-infra__intro {
  margin: 16px 0 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.88;
  color: var(--muted);
}

.page-about .ab-stats {
  display: grid;
  gap: 12px;
  margin-top: 26px;
}

.page-about .ab-stat {
  padding: 18px 16px 20px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--cyan);
  border-radius: var(--radius);
  background: rgba(19, 28, 77, 0.55);
  transition: border-color 0.22s var(--ease), background 0.22s var(--ease);
}

.page-about .ab-stat:hover {
  border-color: var(--cyan);
  background: rgba(19, 28, 77, 0.9);
}

.page-about .ab-stat__num {
  margin: 0;
  font-family: var(--mono);
  font-size: 26px;
  line-height: 1.1;
  letter-spacing: 0.03em;
  color: var(--text);
}

.page-about .ab-stat__label {
  margin: 8px 0 0;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

/* ---------- 阶段成果 ---------- */
.page-about .ab-results-sec {
  padding-block: 46px 20px;
}

.page-about .ab-results {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--line);
  overflow: hidden;
}

.page-about .ab-results li {
  display: grid;
  gap: 6px;
  padding: 18px 16px 20px;
  background: var(--bg-2);
}

.page-about .ab-results__k {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--amber);
}

.page-about .ab-results__v {
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 收尾 ---------- */
.page-about .ab-next {
  padding-block: 40px 64px;
}

.page-about .ab-next__box {
  display: grid;
  gap: 22px;
  padding: 26px 20px 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    linear-gradient(112deg, rgba(53, 242, 224, 0.1), rgba(138, 91, 255, 0.08) 58%, rgba(5, 10, 36, 0) 100%),
    var(--bg-2);
}

.page-about .ab-next__text h2 {
  margin: 0;
  font-size: clamp(20px, 4.6vw, 26px);
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .ab-next__text p {
  margin: 12px 0 0;
  max-width: 58ch;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .ab-next__text a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 242, 224, 0.4);
}

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

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

/* ---------- 平板以上 ---------- */
@media (min-width: 720px) {
  .page-about .ab-hero {
    padding-block: 40px 10px;
  }

  .page-about .ab-hero__frame {
    padding: 38px 32px 42px;
  }

  .page-about .ab-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .ab-phases {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }

  .page-about .ab-results li {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }

  .page-about .ab-eco__facts li {
    grid-template-columns: 108px minmax(0, 1fr);
    gap: 14px;
  }

  .page-about .ab-next__box {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    padding: 30px 32px 32px;
    gap: 30px;
  }

  .page-about .ab-next__actions {
    flex-wrap: nowrap;
  }
}

/* ---------- 桌面：双栏与时间轴细化 ---------- */
@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    gap: 44px;
    align-items: end;
  }

  .page-about .ab-meta {
    padding-top: 0;
    border-top: 0;
    border-left: 1px solid var(--line);
    padding-left: 26px;
  }

  .page-about .ab-tl__item {
    padding-left: 42px;
  }

  .page-about .ab-tl__item:nth-child(1) { padding-bottom: 26px; }
  .page-about .ab-tl__item:nth-child(2) { padding-bottom: 36px; }
  .page-about .ab-tl__item:nth-child(3) { padding-bottom: 48px; }
  .page-about .ab-tl__item:nth-child(4) { padding-bottom: 60px; }

  .page-about .ab-tl::before {
    left: 9px;
  }

  .page-about .ab-tl__dot {
    width: 19px;
    height: 19px;
    top: 8px;
  }

  .page-about .ab-tl__card {
    padding: 22px 24px 24px;
  }

  .page-about .ab-split {
    grid-template-columns: minmax(0, 0.92fr) minmax(0, 1fr);
    gap: 44px;
    align-items: center;
  }

  .page-about .ab-split--flip .ab-split__media {
    order: 2;
  }
}

/* 桌面且有悬停能力时，版本摘要收起，悬停或聚焦再展开 */
@media (min-width: 900px) and (hover: hover) {
  .page-about .ab-tl__more {
    max-height: 0;
    margin-top: 0;
    padding-top: 0;
    border-top-color: transparent;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.28s var(--ease), opacity 0.24s var(--ease),
                margin-top 0.28s var(--ease), padding-top 0.28s var(--ease),
                border-top-color 0.28s var(--ease);
  }

  .page-about .ab-tl__card:hover .ab-tl__more,
  .page-about .ab-tl__card:focus-within .ab-tl__more {
    max-height: 110px;
    margin-top: 12px;
    padding-top: 10px;
    border-top-color: var(--line);
    opacity: 1;
  }
}

@media (min-width: 1200px) {
  .page-about .ab-hero__frame {
    padding: 46px 44px 50px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-tl__item--now .ab-tl__dot::before {
    animation: none;
    opacity: 0.5;
  }

  .page-about .ab-tl__card,
  .page-about .ab-stat {
    transition: none;
  }
}