.page-about {
  background: var(--white);
  color: var(--ink);
  font-family: var(--font-sans);
  overflow-x: hidden;
}

/* ---------- 开篇 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background: var(--night);
  color: var(--white);
  padding: clamp(26px, 4.5vw, 52px) 0 clamp(54px, 8vw, 106px);
}

.page-about .about-hero__bg {
  position: absolute;
  inset: 0;
  z-index: -2;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 42%;
  opacity: .3;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(120% 92% at 10% 6%, rgba(11, 27, 51, .38) 0%, rgba(11, 27, 51, .96) 64%),
    linear-gradient(180deg, rgba(11, 27, 51, .42) 0%, var(--night) 98%);
}

.page-about .about-hero__rule {
  position: absolute;
  right: -8%;
  top: 26%;
  z-index: 0;
  width: 62%;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, var(--gold) 100%);
  transform: rotate(-4deg);
  opacity: .55;
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .breadcrumb {
  color: rgba(255, 255, 255, .6);
  font-size: 13px;
  letter-spacing: .04em;
  margin-bottom: clamp(26px, 4vw, 52px);
}

.page-about .about-hero .breadcrumb a {
  color: rgba(255, 255, 255, .6);
  text-decoration: none;
  transition: color .2s var(--ease);
}

.page-about .about-hero .breadcrumb a:hover,
.page-about .about-hero .breadcrumb a:focus-visible {
  color: var(--gold-soft);
}

.page-about .about-hero .breadcrumb > span[aria-hidden] {
  margin: 0 9px;
  opacity: .45;
}

.page-about .about-hero__kicker {
  margin: 0 0 clamp(14px, 2vw, 22px);
  color: var(--gold-soft);
}

.page-about .about-hero__title {
  margin: 0 0 clamp(18px, 3vw, 32px);
  max-width: 16ch;
  font-size: clamp(34px, 8.5vw, 78px);
  font-weight: 900;
  line-height: 1.06;
  letter-spacing: -.03em;
}

.page-about .about-hero__lede {
  margin: 0 0 clamp(24px, 3.4vw, 38px);
  max-width: 62ch;
  font-size: clamp(16px, 1.5vw, 18px);
  line-height: 1.8;
  color: rgba(255, 255, 255, .78);
}

.page-about .about-hero__foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  margin: 0;
  font-size: 14px;
  color: rgba(255, 255, 255, .58);
}

.page-about .about-hero__foot .mono {
  color: var(--gold-soft);
  font-weight: 700;
  letter-spacing: .08em;
}

.page-about .about-hero__foot a {
  color: var(--white);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 1px solid var(--gold);
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-hero__foot a:hover,
.page-about .about-hero__foot a:focus-visible {
  color: var(--gold-soft);
  border-color: var(--gold-soft);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  position: relative;
  padding: clamp(52px, 8vw, 112px) 0;
}

.page-about .about-chapter--paper {
  background: var(--cream);
}

.page-about .about-chapter--dark {
  background: var(--night);
  color: var(--white);
}

.page-about .about-head {
  position: relative;
  margin-bottom: clamp(26px, 4vw, 48px);
}

.page-about .about-head__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(52px, 11vw, 132px);
  font-weight: 700;
  line-height: .8;
  letter-spacing: -.06em;
  color: var(--gold-soft);
  opacity: .42;
  margin-bottom: clamp(8px, 1.4vw, 18px);
}

.page-about .about-chapter--dark .about-head__num {
  color: var(--gold);
  opacity: .34;
}

.page-about .about-head__title {
  position: relative;
  z-index: 1;
  margin: 0;
  padding-left: clamp(14px, 1.6vw, 20px);
  border-left: 3px solid var(--gold);
  font-size: clamp(26px, 4.6vw, 46px);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -.02em;
}

.page-about .about-chapter--dark .about-head__title {
  color: var(--white);
}

.page-about .about-body {
  max-width: 62%;
}

.page-about .about-p {
  margin: 0 0 1.1em;
  font-size: 17px;
  line-height: 1.8;
  color: var(--ink);
}

.page-about .about-p:last-child {
  margin-bottom: 0;
}

.page-about .about-chapter--dark .about-p {
  color: rgba(255, 255, 255, .82);
}

.page-about .about-p a,
.page-about .closing-note a {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--gold);
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-p a:hover,
.page-about .about-p a:focus-visible,
.page-about .closing-note a:hover,
.page-about .closing-note a:focus-visible {
  color: var(--gold-ink);
  border-color: var(--gold-ink);
}

/* ---------- 01 合作三件事 ---------- */
.page-about .partner-blocks {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(14px, 2.2vw, 26px);
  margin-top: clamp(30px, 4.4vw, 52px);
}

.page-about .partner-block {
  position: relative;
  padding: clamp(20px, 3vw, 30px);
  background: var(--white);
  box-shadow: 0 22px 40px -34px rgba(11, 27, 51, .55);
}

.page-about .partner-block__idx {
  display: block;
  margin: 0 0 12px;
  font-size: 13px;
  letter-spacing: .16em;
  color: var(--gold-ink);
}

.page-about .partner-block .card__title {
  margin: 0 0 10px;
  font-size: 19px;
  font-weight: 800;
  line-height: 1.35;
  letter-spacing: -.01em;
}

.page-about .partner-block .card__body {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--slate);
}

/* ---------- 02 版本时间线 ---------- */
.page-about .version-track {
  list-style: none;
  margin: clamp(30px, 4.4vw, 52px) 0 0;
  padding: 0;
  background-image: linear-gradient(180deg, var(--gold) 0%, var(--gold-soft) 62%, rgba(201, 162, 39, .12) 100%);
  background-size: 2px 100%;
  background-position: 7px 0;
  background-repeat: no-repeat;
}

.page-about .version-track__item {
  position: relative;
  padding-left: clamp(26px, 4.6vw, 58px);
  margin-bottom: clamp(24px, 3.4vw, 42px);
}

.page-about .version-track__item:last-child {
  margin-bottom: 0;
}

.page-about .version-track__marker {
  position: absolute;
  left: 0;
  top: 8px;
  width: 14px;
  height: 14px;
  box-sizing: border-box;
  border-radius: 50%;
  background: var(--white);
  border: 2px solid var(--gold);
}

.page-about .version-track__item:last-child .version-track__marker {
  background: var(--gold);
  box-shadow: 0 0 0 7px rgba(201, 162, 39, .18);
}

.page-about .version-track__panel {
  padding: clamp(18px, 2.6vw, 28px);
  background: var(--white);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--gold);
  border-radius: var(--radius);
}

.page-about .version-track__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.page-about .version-track__ver {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--gold-ink);
}

.page-about .version-track__title {
  margin: 0 0 8px;
  font-size: clamp(18px, 2.1vw, 22px);
  font-weight: 800;
  line-height: 1.35;
  letter-spacing: -.01em;
}

.page-about .version-track__body {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--slate);
}

/* ---------- 03 校对 ---------- */
.page-about .proof-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 44px);
  align-items: start;
}

.page-about .proof-layout__media {
  margin: 0;
}

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

/* ---------- 04 内容系列 ---------- */
.page-about .series-list {
  list-style: none;
  margin: clamp(28px, 4vw, 46px) 0 0;
  padding: 0;
  border-bottom: 1px solid var(--rule);
}

.page-about .series-list__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  padding: clamp(18px, 2.6vw, 26px) 0;
  border-top: 1px solid var(--rule);
}

.page-about .series-list__text {
  margin: 0;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--slate);
}

.page-about .closing-note {
  margin-top: clamp(26px, 4vw, 44px);
  padding-top: clamp(20px, 3vw, 30px);
  border-top: 1px solid var(--rule);
  font-size: 15px;
  line-height: 1.85;
  color: var(--slate);
}

/* ---------- 05 规模与覆盖 ---------- */
.page-about .reach-cover {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border-radius: var(--radius);
  outline: 1px solid var(--rule-dark);
  outline-offset: -1px;
  margin-top: clamp(28px, 4vw, 46px);
}

.page-about .reach-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(24px, 3.6vw, 40px);
  background: var(--rule-dark);
  border: 1px solid var(--rule-dark);
}

.page-about .reach-cell {
  background: var(--night-2);
  padding: clamp(18px, 2.6vw, 28px);
}

.page-about .reach-cell__num {
  display: block;
  margin-bottom: 9px;
  font-family: var(--font-mono);
  font-size: clamp(23px, 3.2vw, 34px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--gold-soft);
}

.page-about .reach-cell__label {
  display: block;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(255, 255, 255, .64);
}

/* ---------- 06 下一步 ---------- */
.page-about .next-list {
  list-style: none;
  margin: clamp(22px, 3.2vw, 36px) 0 0;
  padding: 0;
}

.page-about .next-list__item {
  position: relative;
  margin-bottom: 16px;
  padding-left: 26px;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink);
}

.page-about .next-list__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 13px;
  width: 14px;
  height: 2px;
  background: var(--gold);
}

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .page-about .about-body {
    max-width: 100%;
  }
}

@media (min-width: 760px) {
  .page-about .partner-blocks {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .partner-block:nth-child(2) {
    margin-top: 34px;
  }

  .page-about .partner-block:nth-child(3) {
    margin-top: 68px;
  }

  .page-about .series-list__item {
    grid-template-columns: 168px minmax(0, 1fr);
    gap: clamp(20px, 4vw, 56px);
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .proof-layout {
    grid-template-columns: 6fr 5fr;
    gap: clamp(32px, 6vw, 84px);
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .about-hero__rule {
    opacity: .3;
  }

  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}