.page-about {
  --about-toc-w: 240px;
  --about-hair: rgba(27, 42, 37, 0.2);
  --about-hair-strong: rgba(27, 42, 37, 0.42);
  --about-paper-lift: #FBF8EF;
  background: var(--paper);
  color: var(--ink);
  overflow-x: clip;
}

/* ============ 封面首屏 ============ */
.page-about .about-hero {
  position: relative;
  background: linear-gradient(158deg, var(--pitch) 0%, var(--pitch) 44%, var(--night) 100%);
  color: var(--paper);
  padding: clamp(18px, 3vw, 30px) 0 clamp(72px, 10vw, 132px);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - clamp(28px, 5vw, 58px)), 0 100%);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(245, 241, 230, 0.055) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(245, 241, 230, 0.055) 1px, transparent 1px);
  background-size: 56px 56px;
  pointer-events: none;
  z-index: 0;
}

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

.page-about .about-hero__crumb,
.page-about .about-hero__crumb a,
.page-about .about-hero__crumb li {
  color: var(--on-dark);
}

.page-about .about-hero__split {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
  margin-top: clamp(22px, 3.4vw, 40px);
}

.page-about .about-hero__lead h1 {
  margin: 12px 0 0;
  font-size: clamp(28px, 5.4vw, 58px);
  line-height: 1.06;
  font-weight: 800;
  letter-spacing: -0.015em;
  max-width: 15em;
  color: var(--paper);
}

.page-about .about-hero__intro {
  margin: clamp(14px, 2vw, 22px) 0 0;
  max-width: 34em;
  font-size: clamp(15px, 0.42vw + 13.8px, 17.5px);
  line-height: 1.78;
  color: var(--on-dark);
}

.page-about .about-hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(20px, 3vw, 32px);
}

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

.page-about .about-hero__figure::before {
  content: "";
  position: absolute;
  top: -8px;
  left: -8px;
  width: 46px;
  height: 46px;
  border-top: 3px solid var(--gold);
  border-left: 3px solid var(--gold);
  pointer-events: none;
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid rgba(245, 241, 230, 0.22);
}

.page-about .about-hero__stats {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(14px, 2.4vw, 26px);
  margin: clamp(30px, 4.4vw, 52px) 0 0;
  padding: clamp(18px, 3vw, 28px) 0 0;
  border-top: 1px solid rgba(245, 241, 230, 0.18);
}

.page-about .about-hero__stat {
  min-width: 0;
}

.page-about .about-hero__stat-label {
  display: block;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--on-dark-soft);
}

.page-about .about-hero__stat-value {
  display: block;
  margin-top: 8px;
  font-family: var(--font-num);
  font-size: clamp(30px, 4.6vw, 48px);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.025em;
  color: var(--gold);
}

.page-about .about-hero__stat-unit {
  margin-left: 4px;
  font-size: 0.4em;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--on-dark);
}

/* ============ 主体骨架 ============ */
.page-about .about-body {
  display: grid;
  gap: clamp(28px, 4vw, 48px);
  padding: clamp(40px, 6.5vw, 84px) 0 clamp(88px, 12vw, 152px);
}

.page-about .about-flow {
  min-width: 0;
}

/* ============ 阶段目录 ============ */
.page-about .about-toc {
  min-width: 0;
}

.page-about .about-toc__label {
  margin: 0 0 12px;
  padding-bottom: 10px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--ink-soft);
  border-bottom: 1px solid var(--about-hair);
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0 0 4px;
  display: flex;
  gap: 4px;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-toc__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-toc__link {
  display: flex;
  align-items: baseline;
  gap: 9px;
  padding: 9px 12px;
  white-space: nowrap;
  color: var(--ink-soft);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color 0.24s var(--ease), border-color 0.24s var(--ease), background-color 0.24s var(--ease);
}

.page-about .about-toc__link:hover {
  color: var(--ink);
  background: var(--paper-3);
}

.page-about .about-toc__link.is-active {
  color: var(--ink);
  border-left-color: var(--gold);
  background: var(--paper-2);
}

.page-about .about-toc__link .u-toc__num {
  font-family: var(--font-num);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--gold-deep);
}

.page-about .about-toc__link.is-active .u-toc__num {
  color: var(--pitch);
}

/* ============ 章节 ============ */
.page-about .about-sec {
  margin-top: clamp(44px, 6.5vw, 84px);
  padding-top: clamp(40px, 6vw, 78px);
  border-top: 1px solid var(--about-hair);
  scroll-margin-top: 120px;
}

.page-about .about-sec:first-child {
  margin-top: 0;
  padding-top: 0;
  border-top: 0;
}

.page-about .about-sec__head {
  display: flex;
  align-items: baseline;
  gap: clamp(12px, 2vw, 20px);
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .about-sec__no {
  flex: none;
  font-family: var(--font-num);
  font-size: clamp(20px, 3vw, 32px);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--gold-deep);
}

.page-about .about-sec__title {
  margin: 0;
  font-size: clamp(21px, 3.2vw, 38px);
  line-height: 1.14;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-p {
  max-width: 34em;
  margin: 0 0 1.05em;
  font-size: clamp(15.5px, 0.42vw + 14.2px, 17px);
  line-height: 1.78;
  color: var(--ink);
}

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

.page-about .about-p a {
  color: var(--gold-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.page-about .about-p a:hover {
  color: var(--pitch);
}

/* ============ 数字锚点 ============ */
.page-about .about-anchor {
  position: relative;
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin-top: clamp(26px, 4vw, 44px);
  padding-top: clamp(18px, 2.6vw, 28px);
  border-top: 1px solid var(--about-hair-strong);
}

.page-about .about-anchor::before {
  content: "";
  position: absolute;
  top: -5px;
  left: 0;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 0 4px rgba(63, 224, 180, 0.16);
}

.page-about .about-anchor__num {
  font-family: var(--font-num);
  font-size: clamp(36px, 6.4vw, 68px);
  font-weight: 800;
  line-height: 0.9;
  letter-spacing: -0.03em;
  color: var(--pitch);
}

.page-about .about-anchor__text {
  max-width: 22em;
  font-size: clamp(13px, 0.3vw + 12.4px, 15px);
  line-height: 1.6;
  color: var(--ink-soft);
}

/* ============ 团队条带 ============ */
.page-about .about-team {
  list-style: none;
  margin: clamp(22px, 3.4vw, 34px) 0 clamp(22px, 3.4vw, 34px);
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
}

.page-about .about-team__item {
  display: grid;
  grid-template-columns: 82px minmax(0, 1fr) 40px;
  align-items: center;
  gap: 12px;
  padding: 13px 14px;
  background: var(--paper);
}

.page-about .about-team__name {
  font-size: 13.5px;
  font-weight: 700;
  color: var(--ink);
  white-space: nowrap;
}

.page-about .about-team__track {
  position: relative;
  height: 9px;
  background: var(--paper-2);
  overflow: hidden;
}

.page-about .about-team__bar {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--pitch) 0%, var(--pitch) 62%, var(--teal) 100%);
}

.page-about .about-team__item:nth-child(1) .about-team__bar { width: 39%; }
.page-about .about-team__item:nth-child(2) .about-team__bar { width: 20%; }
.page-about .about-team__item:nth-child(3) .about-team__bar { width: 26%; }
.page-about .about-team__item:nth-child(4) .about-team__bar { width: 15%; }

.page-about .about-team__num {
  font-family: var(--font-num);
  font-size: 22px;
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  text-align: right;
  color: var(--gold-deep);
}

/* ============ 版本卡片 ============ */
.page-about .about-versions {
  list-style: none;
  margin: clamp(24px, 4vw, 40px) 0 0;
  padding: 0;
  display: grid;
  gap: clamp(18px, 3vw, 30px);
}

.page-about .about-version {
  position: relative;
  background: var(--paper-3);
  border: 1px solid var(--about-hair);
  padding: clamp(18px, 2.6vw, 28px);
  box-shadow: 6px 6px 0 var(--paper-2);
  transition: background-color 0.28s var(--ease), box-shadow 0.28s var(--ease), border-color 0.28s var(--ease);
}

.page-about .about-version:hover,
.page-about .about-version:focus-within {
  background: var(--about-paper-lift);
  border-color: var(--about-hair-strong);
  box-shadow: 10px 10px 0 var(--paper-2);
}

.page-about .about-version__inner {
  transition: transform 0.28s var(--ease);
}

.page-about .about-version:hover .about-version__inner,
.page-about .about-version:focus-within .about-version__inner {
  transform: translateY(-3px);
}

.page-about .about-version__tag {
  display: inline-block;
  padding: 3px 10px;
  font-family: var(--font-num);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--paper);
  background: var(--pitch);
}

.page-about .about-version__title {
  margin: 14px 0 8px;
  font-size: clamp(16.5px, 1.4vw, 20px);
  line-height: 1.35;
  font-weight: 800;
  letter-spacing: -0.005em;
  color: var(--ink);
}

.page-about .about-flow .about-version__desc {
  max-width: none;
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--ink-soft);
  transition: color 0.28s var(--ease);
}

.page-about .about-version:hover .about-version__desc,
.page-about .about-version:focus-within .about-version__desc {
  color: var(--ink);
}

/* ============ 合作生态 ============ */
.page-about .about-eco {
  list-style: none;
  margin: clamp(22px, 3.6vw, 36px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
}

.page-about .about-eco__item {
  position: relative;
  padding: clamp(18px, 2.6vw, 28px);
  background: var(--paper);
  transition: background-color 0.26s var(--ease);
}

.page-about .about-eco__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--gold);
  transform: scaleY(0);
  transform-origin: top center;
  transition: transform 0.3s var(--ease);
}

.page-about .about-eco__item:hover {
  background: var(--paper-3);
}

.page-about .about-eco__item:hover::before {
  transform: scaleY(1);
}

.page-about .about-eco__num {
  display: block;
  font-family: var(--font-num);
  font-size: clamp(32px, 4.8vw, 48px);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--pitch);
}

.page-about .about-eco__name {
  display: block;
  margin-top: 10px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.page-about .about-eco__desc {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--ink-soft);
}

/* ============ 图带 ============ */
.page-about .about-figure {
  margin: clamp(28px, 4.4vw, 48px) 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid var(--about-hair);
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  max-width: 42em;
  font-size: 12.5px;
  line-height: 1.68;
  color: var(--ink-soft);
}

/* ============ 联系面板 ============ */
.page-about .about-contact-panel {
  position: relative;
  margin-top: clamp(26px, 4vw, 44px);
  padding: clamp(24px, 4vw, 46px);
  background: var(--pitch);
  color: var(--paper);
  overflow: hidden;
}

.page-about .about-contact-panel::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--gold) 0%, var(--teal) 100%);
}

.page-about .about-contact-panel__title {
  margin: 0;
  font-size: clamp(18px, 2vw, 24px);
  font-weight: 800;
  letter-spacing: -0.005em;
  color: var(--paper);
}

.page-about .about-contact-panel__lead {
  margin: 10px 0 0;
  max-width: 34em;
  font-size: 14.5px;
  line-height: 1.74;
  color: var(--on-dark);
}

.page-about .about-contact-panel__list {
  list-style: none;
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: rgba(245, 241, 230, 0.16);
  border-top: 1px solid rgba(245, 241, 230, 0.16);
  border-bottom: 1px solid rgba(245, 241, 230, 0.16);
}

.page-about .about-contact-panel__row {
  display: grid;
  gap: 4px;
  padding: 14px 0;
  background: var(--pitch);
}

.page-about .about-contact-panel__label {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--teal);
}

.page-about .about-contact-panel__value {
  font-size: 15.5px;
  line-height: 1.65;
  color: var(--paper);
  word-break: break-word;
}

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

/* ============ 浮动按钮 ============ */
.page-about .about-fabs {
  position: fixed;
  right: clamp(12px, 2vw, 24px);
  bottom: clamp(12px, 2vw, 24px);
  z-index: 30;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .about-fab {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--paper);
  background: var(--night);
  border: 1px solid rgba(245, 241, 230, 0.2);
  text-decoration: none;
  transition: background-color 0.24s var(--ease), color 0.24s var(--ease);
}

.page-about .about-fab:hover {
  background: var(--gold);
  color: var(--ink);
}

/* ============ 断点 ============ */
@media (min-width: 640px) {
  .page-about .about-team__item {
    grid-template-columns: 110px minmax(0, 1fr) 56px;
    padding: 15px 20px;
    gap: 16px;
  }
}

@media (min-width: 720px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 900px) {
  .page-about .about-hero__split {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    align-items: end;
    gap: clamp(36px, 5vw, 76px);
  }
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-toc-w) minmax(0, 1fr);
    gap: clamp(44px, 5.6vw, 92px);
    align-items: start;
  }

  .page-about .about-toc {
    position: sticky;
    top: 108px;
  }

  .page-about .about-toc__list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-toc__label {
    letter-spacing: 0.2em;
  }

  .page-about .about-contact-panel__row {
    grid-template-columns: 108px minmax(0, 1fr);
    align-items: baseline;
    gap: 20px;
  }
}

@media (max-width: 480px) {
  .page-about .about-fabs {
    display: none;
  }

  .page-about .about-anchor__text {
    max-width: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-version,
  .page-about .about-version__inner,
  .page-about .about-version__desc,
  .page-about .about-eco__item::before,
  .page-about .about-team__bar,
  .page-about .about-fab,
  .page-about .about-toc__link {
    transition: none;
  }

  .page-about .about-version:hover .about-version__inner,
  .page-about .about-version:focus-within .about-version__inner {
    transform: none;
  }
}