.page-about {
  --pa-dark-shadow: 6px 6px 0 rgba(0, 0, 0, .55);
  --pa-paper-shadow: 6px 6px 0 var(--brown);
  --pa-muted-paper: #6B5A48;
  --pa-line-dark: rgba(141, 162, 192, .26);
  --pa-deep-orange: #C2410C;
  background-color: var(--ink);
  color: var(--slate);
  font-family: var(--font-body);
  overflow-x: clip;
}

.page-about a:focus-visible,
.page-about [tabindex]:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 3px;
}

.page-about .crumbs {
  padding-top: 18px;
}

/* ---------- 首屏 ---------- */

.page-about .hist-hero {
  position: relative;
  padding: clamp(26px, 4vw, 54px) 0 clamp(30px, 4.5vw, 60px);
  border-bottom: 2px solid var(--pa-line-dark);
  background-image:
    linear-gradient(rgba(141, 162, 192, .07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(141, 162, 192, .07) 1px, transparent 1px);
  background-size: 48px 48px;
}

.page-about .hist-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(22px, 3vw, 40px);
  align-items: end;
}

.page-about .hist-hero h1 {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(30px, 6.4vw, 62px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .hist-hero__lead {
  margin: 18px 0 0;
  max-width: 64ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.95;
  color: var(--slate);
}

.page-about .hist-hero__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .hist-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  align-content: start;
}

.page-about .hist-fact {
  position: relative;
  padding: 14px 14px 13px;
  background: var(--panel);
  border: 1px solid var(--pa-line-dark);
  border-left: 3px solid var(--cyan);
  transition: transform .22s ease, border-color .22s ease;
}

.page-about .hist-fact:hover {
  transform: translateY(-4px);
  border-color: var(--cyan);
}

.page-about .hist-fact:nth-child(2) {
  border-left-color: var(--orange);
}

.page-about .hist-fact:nth-child(3) {
  border-left-color: var(--green);
}

.page-about .hist-fact:nth-child(4) {
  border-left-color: #B23AFF;
}

.page-about .hist-fact__num {
  margin: 0;
  font-family: var(--font-data);
  font-weight: 700;
  font-size: clamp(22px, 3.2vw, 32px);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--cyan);
}

.page-about .hist-fact:nth-child(2) .hist-fact__num { color: var(--orange); }
.page-about .hist-fact:nth-child(3) .hist-fact__num { color: var(--green); }
.page-about .hist-fact:nth-child(4) .hist-fact__num { color: #D89BFF; }

.page-about .hist-fact__cap {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--slate);
}

/* ---------- 通用区块 ---------- */

.page-about .pa-sec {
  padding: clamp(40px, 6vw, 84px) 0;
}

.page-about .sec-head {
  margin: 0 0 clamp(20px, 3vw, 34px);
  padding-left: 16px;
  border-left: 4px solid var(--orange);
}

.page-about .sec-head h2 {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 3.6vw, 40px);
  line-height: 1.22;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .paper-sec .sec-head {
  border-left-color: var(--brown);
}

.page-about .paper-sec .sec-head h2 {
  color: var(--ink-text);
}

.page-about .paper-sec .kicker {
  color: #9E3B12;
}

/* ---------- 图片块 ---------- */

.page-about .pa-fig {
  margin: 0;
  overflow: hidden;
  background: var(--panel);
  border: 2px solid var(--pa-line-dark);
}

.page-about .pa-fig img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .pa-cap {
  padding: 10px 14px;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--slate);
  border-top: 1px solid var(--pa-line-dark);
}

.page-about .paper-sec .pa-fig {
  border-color: var(--brown);
  box-shadow: var(--pa-paper-shadow);
  background: #E7DBC5;
}

.page-about .paper-sec .pa-cap {
  color: var(--pa-muted-paper);
  border-top-color: rgba(26, 20, 16, .2);
  background: rgba(255, 255, 255, .35);
}

/* ---------- 起点 ---------- */

.page-about .origin__fig {
  margin-bottom: clamp(22px, 3vw, 36px);
}

.page-about .origin__cols {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(18px, 2.6vw, 34px);
}

.page-about .origin__col h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(17px, 1.9vw, 21px);
  line-height: 1.4;
  color: var(--paper);
  letter-spacing: -0.01em;
}

.page-about .origin__col h3::before {
  content: "";
  display: block;
  width: 28px;
  height: 4px;
  margin-bottom: 12px;
  background: var(--grad);
}

.page-about .origin__col p {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.95;
  color: var(--slate);
}

/* ---------- 版本时间轴 ---------- */

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

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 19px;
  top: 14px;
  bottom: 0;
  width: 4px;
  border-radius: 2px;
  background-image: var(--grad);
  opacity: .8;
}

.page-about .tl__item {
  position: relative;
  padding: 0 0 clamp(20px, 3vw, 34px) 48px;
}

.page-about .tl__item:last-child {
  padding-bottom: 6px;
}

.page-about .tl__item::before {
  content: "";
  position: absolute;
  left: 12px;
  top: 20px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--ink);
  border: 3px solid var(--cyan);
  box-shadow: 0 0 0 4px rgba(43, 240, 214, .12);
  z-index: 1;
}

.page-about .tl__item:nth-child(even)::before {
  border-color: var(--orange);
  box-shadow: 0 0 0 4px rgba(255, 122, 47, .14);
}

.page-about .tl__card {
  max-width: 100%;
  padding: clamp(15px, 2vw, 24px);
  background: var(--panel);
  border: 2px solid var(--pa-line-dark);
  border-left: 4px solid var(--orange);
  transition: transform .22s ease, border-color .22s ease, box-shadow .22s ease;
}

.page-about .tl__card:hover,
.page-about .tl__card:focus {
  transform: translateY(-4px);
  border-color: var(--cyan);
  box-shadow: 0 10px 0 -6px rgba(43, 240, 214, .45);
}

.page-about .tl__ver {
  margin: 0;
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--orange);
}

.page-about .tl__name {
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(19px, 2.4vw, 27px);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .tl__desc {
  margin: 10px 0 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.9;
  color: var(--slate);
}

.page-about .tl__more {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height .3s ease, opacity .25s ease;
}

.page-about .tl__more p {
  margin: 12px 0 0;
  padding-top: 12px;
  border-top: 1px dashed rgba(141, 162, 192, .32);
  font-size: 14px;
  line-height: 1.9;
  color: var(--slate);
}

.page-about .tl__card:hover .tl__more,
.page-about .tl__card:focus .tl__more {
  max-height: 260px;
  opacity: 1;
}

@media (min-width: 900px) {
  .page-about .tl__item:nth-child(odd) .tl__card {
    max-width: min(100%, 880px);
  }
  .page-about .tl__item:nth-child(even) .tl__card {
    max-width: min(100%, 620px);
  }
}

/* ---------- 团队 ---------- */

.page-about .paper-sec {
  background-color: var(--paper);
  color: var(--ink-text);
  border-top: 3px solid var(--brown);
  border-bottom: 3px solid var(--brown);
}

.page-about .paper-sec p {
  color: #3B3026;
}

.page-about .team__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(22px, 3vw, 38px);
  align-items: start;
}

.page-about .team__lead {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.95;
  color: #3B3026;
}

.page-about .team__list {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .team__row {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 16px;
  padding: 18px 0;
  border-top: 2px solid rgba(26, 20, 16, .16);
}

.page-about .team__num {
  display: grid;
  place-items: center;
  width: 62px;
  height: 62px;
  background: var(--ink);
  color: var(--cyan);
  border: 2px solid var(--brown);
  font-family: var(--font-data);
  font-weight: 700;
  font-size: 24px;
  line-height: 1;
}

.page-about .team__row-body h3 {
  margin: 2px 0 0;
  font-family: var(--font-display);
  font-size: 18px;
  line-height: 1.4;
  color: var(--ink-text);
}

.page-about .team__row-body p {
  margin: 8px 0 0;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--pa-muted-paper);
}

/* ---------- 覆盖与规模 ---------- */

.page-about .reach__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--gap);
}

.page-about .reach__stat {
  position: relative;
  padding: 20px 16px 16px;
  background: var(--panel);
  border: 1px solid var(--pa-line-dark);
  overflow: hidden;
  transition: transform .22s ease, border-color .22s ease;
}

.page-about .reach__stat:hover {
  transform: translateY(-4px);
  border-color: var(--cyan);
}

.page-about .reach__stat::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 36px;
  height: 36px;
  background-image: var(--grad);
  clip-path: polygon(100% 0, 0 0, 100% 100%);
  opacity: .9;
}

.page-about .reach__num {
  margin: 0;
  font-family: var(--font-data);
  font-weight: 700;
  font-size: clamp(30px, 4.6vw, 46px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.page-about .reach__num span {
  margin-left: 3px;
  font-size: .5em;
  color: var(--slate);
}

.page-about .reach__label {
  margin: 12px 0 0;
  font-size: 14.5px;
  color: var(--paper);
}

.page-about .reach__sub {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--slate);
}

.page-about .reach__note {
  margin: clamp(20px, 3vw, 32px) 0 0;
  max-width: 70ch;
  padding-left: 16px;
  border-left: 3px solid var(--green);
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--slate);
}

/* ---------- 合作生态 ---------- */

.page-about .partners__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(22px, 3vw, 38px);
  align-items: center;
}

.page-about .partners__body p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.95;
  color: #3B3026;
}

.page-about .partners__points {
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .partners__points li {
  position: relative;
  margin-bottom: 12px;
  padding-left: 26px;
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--pa-muted-paper);
}

.page-about .partners__points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 12px;
  width: 13px;
  height: 4px;
  background: var(--pa-deep-orange);
}

/* ---------- 持续运营 ---------- */

.page-about .keep__steps {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap);
  counter-reset: keep;
}

.page-about .keep__step {
  position: relative;
  padding: 18px 16px 20px;
  background: var(--panel);
  border: 1px solid var(--pa-line-dark);
  border-top: 3px solid var(--cyan);
  counter-increment: keep;
  transition: transform .22s ease, background-color .22s ease;
}

.page-about .keep__step:hover {
  transform: translateY(-4px);
  background: #15233E;
}

.page-about .keep__step::before {
  content: counter(keep, decimal-leading-zero);
  display: block;
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--orange);
}

.page-about .keep__step h3 {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-size: 17px;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .keep__step p {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--slate);
}

.page-about .keep__callout {
  margin: clamp(22px, 3vw, 32px) 0 0;
  font-size: 15px;
  line-height: 1.9;
  color: var(--slate);
}

.page-about .keep__callout a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.page-about .keep__callout a:hover {
  color: var(--paper);
}

/* ---------- 收尾数据条 ---------- */

.page-about .closer {
  padding: clamp(34px, 5vw, 70px) 0 clamp(46px, 6vw, 88px);
}

.page-about .closer__title {
  margin: 0 0 clamp(18px, 2.4vw, 28px);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(20px, 2.6vw, 28px);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .closer__bar {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--pa-line-dark);
  border: 2px solid var(--pa-line-dark);
}

.page-about .closer__cell {
  padding: 20px 16px 18px;
  background: var(--panel);
}

.page-about .closer__num {
  margin: 0;
  font-family: var(--font-data);
  font-weight: 700;
  font-size: clamp(24px, 3.4vw, 36px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .closer__num span {
  margin-left: 2px;
  font-size: .5em;
  color: var(--cyan);
}

.page-about .closer__cap {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--slate);
}

.page-about .closer__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .closer__note {
  margin: 18px 0 0;
  font-size: 14px;
  line-height: 1.9;
  color: var(--slate);
}

.page-about .closer__note a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.page-about .closer__note a:hover {
  color: var(--paper);
}

/* ---------- 响应式 ---------- */

@media (min-width: 760px) {
  .page-about .keep__steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 860px) {
  .page-about .origin__cols {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
  }
}

@media (min-width: 900px) {
  .page-about .hist-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
  }

  .page-about .team__grid {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
  }

  .page-about .partners__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
  }

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

@media (min-width: 1060px) {
  .page-about .keep__steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (max-width: 560px) {
  .page-about .hist-facts {
    grid-template-columns: 1fr;
  }

  .page-about .reach__stats {
    grid-template-columns: 1fr;
  }

  .page-about .tl__item {
    padding-left: 40px;
  }

  .page-about .tl::before {
    left: 15px;
  }

  .page-about .tl__item::before {
    left: 8px;
    width: 16px;
    height: 16px;
    top: 21px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl__card,
  .page-about .tl__more,
  .page-about .hist-fact,
  .page-about .reach__stat,
  .page-about .keep__step {
    transition: none;
  }

  .page-about .tl__card:hover,
  .page-about .tl__card:focus,
  .page-about .hist-fact:hover,
  .page-about .reach__stat:hover,
  .page-about .keep__step:hover {
    transform: none;
  }
}