.page-about {
  --about-accent: var(--red);
  --about-accent-2: var(--gold);
  --about-rail-w: 148px;
  position: relative;
  background: var(--ink);
  color: var(--bone);
  padding-bottom: clamp(56px, 8vw, 104px);
}

.page-about .about-crumb {
  padding-top: clamp(16px, 3vw, 28px);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding: clamp(20px, 3.5vw, 40px) 0 clamp(48px, 7vw, 88px);
  background:
    radial-gradient(120% 86% at 92% -10%, rgba(200, 16, 46, 0.34), transparent 62%),
    radial-gradient(86% 70% at 2% 108%, rgba(242, 193, 78, 0.13), transparent 64%),
    var(--ink-deep);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: -8%;
  top: 34%;
  width: 62%;
  height: 180px;
  background: linear-gradient(90deg, rgba(200, 16, 46, 0.22), rgba(242, 193, 78, 0.06) 70%, transparent);
  transform: skewY(-5deg);
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(26px, 4vw, 48px);
  align-items: end;
}

.page-about .about-hero__copy h1 {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-size: clamp(32px, 6.2vw, 68px);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--bone);
  max-width: 15em;
}

.page-about .about-hero__copy .lede {
  margin: 20px 0 0;
  max-width: 36em;
  font-size: clamp(16px, 1.55vw, 18px);
  line-height: 1.9;
  color: var(--bone);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: clamp(26px, 4vw, 38px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px 20px;
  max-width: 520px;
}

.page-about .about-hero__facts li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--hair);
}

.page-about .about-hero__num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
  letter-spacing: -0.02em;
}

.page-about .about-hero__label {
  font-size: 13px;
  color: var(--mist);
  letter-spacing: 0.02em;
}

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

.page-about .about-hero__figure .figure__frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--r-lg);
  border: 1px solid var(--hair);
  box-shadow: var(--shadow-card);
  background: var(--graphite);
}

.page-about .about-hero__figure .figure__frame::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 58%;
  background: linear-gradient(to top, rgba(15, 15, 18, 0.95), rgba(15, 15, 18, 0));
  pointer-events: none;
}

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

/* ---------- 主体框架 ---------- */

.page-about .about-body {
  padding-top: clamp(48px, 7vw, 92px);
}

.page-about .about-body__grid {
  display: grid;
  gap: clamp(18px, 3vw, 36px);
}

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

/* ---------- 移动端章节下拉 ---------- */

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

.page-about .about-index {
  border: 1px solid var(--hair);
  border-radius: var(--r-pill);
  background: var(--graphite);
}

.page-about .about-index summary {
  cursor: pointer;
  list-style: none;
  padding: 13px 22px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--gold-soft);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.page-about .about-index summary::-webkit-details-marker {
  display: none;
}

.page-about .about-index summary::after {
  content: "＋";
  font-size: 15px;
  color: var(--gold);
}

.page-about .about-index[open] summary::after {
  content: "－";
}

.page-about .about-index summary:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
  border-radius: var(--r-pill);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 6px 14px 16px;
  display: grid;
  gap: 2px;
}

.page-about .about-index__list a {
  display: block;
  padding: 9px 10px;
  border-radius: var(--r-md);
  color: var(--bone);
  text-decoration: none;
  font-size: 14.5px;
  line-height: 1.5;
}

.page-about .about-index__list a:hover,
.page-about .about-index__list a:focus-visible {
  background: rgba(200, 16, 46, 0.22);
  color: var(--gold-soft);
}

/* ---------- 桌面端左侧刻度线 ---------- */

.page-about .about-rail__inner {
  display: none;
}

/* ---------- 章节通用 ---------- */

.page-about .about-section {
  padding-bottom: clamp(56px, 8vw, 96px);
  scroll-margin-top: 120px;
}

.page-about .about-section:last-of-type {
  padding-bottom: clamp(40px, 5vw, 64px);
}

.page-about .about-section__head h2 {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-size: clamp(25px, 3.8vw, 42px);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.015em;
  color: var(--bone);
  max-width: 18em;
}

.page-about .about-section__lead {
  margin: 20px 0 0;
  font-size: clamp(18px, 2.1vw, 25px);
  font-weight: 600;
  line-height: 1.55;
  color: var(--gold-soft);
  max-width: 24em;
  border-left: 3px solid var(--red);
  padding-left: 18px;
}

.page-about .about-section .prose p {
  margin: 18px 0 0;
  max-width: 36em;
  font-size: 16.5px;
  line-height: 1.95;
  color: var(--bone);
}

/* ---------- 团队卡组 ---------- */

.page-about .about-team__hint {
  margin: 24px 0 12px;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.page-about .about-team {
  display: flex;
  gap: 14px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  padding: 4px 4px 18px;
  margin: 0 -4px;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-team::-webkit-scrollbar {
  height: 6px;
}

.page-about .about-team::-webkit-scrollbar-thumb {
  background: var(--red-deep);
  border-radius: var(--r-pill);
}

.page-about .about-team-card {
  scroll-snap-align: start;
  flex: 0 0 78%;
  position: relative;
  padding: 24px 20px 26px;
  border-radius: var(--r-md);
  border: 1px solid var(--hair);
  background:
    linear-gradient(180deg, rgba(42, 42, 48, 0.96), rgba(26, 26, 26, 0.9));
  box-shadow: var(--shadow-card);
  transition: transform 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .about-team-card::before {
  content: "";
  position: absolute;
  left: 20px;
  top: 0;
  width: 46px;
  height: 3px;
  background: linear-gradient(90deg, var(--red), var(--gold));
  border-radius: 0 0 3px 3px;
}

.page-about .about-team-card:hover {
  transform: translateY(-6px);
  border-color: var(--gold);
}

.page-about .about-team-card__tag {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--gold);
}

.page-about .about-team-card h3 {
  margin: 10px 0 0;
  font-size: 18px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--bone);
}

.page-about .about-team-card p:last-child {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-team__note p:first-child {
  margin-top: 22px;
  padding-left: 18px;
  border-left: 2px solid var(--hair-strong);
  color: var(--mist);
}

/* ---------- 流程 ---------- */

.page-about .about-flow__grid {
  margin-top: 30px;
  display: grid;
  gap: 28px;
}

.page-about .about-flow__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
  counter-reset: none;
}

.page-about .about-flow__step {
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr);
  gap: 14px;
  padding: 18px 0;
  border-top: 1px solid var(--hair);
}

.page-about .about-flow__step:last-child {
  border-bottom: 1px solid var(--hair);
}

.page-about .about-flow__num {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--red);
  letter-spacing: -0.02em;
}

.page-about .about-flow__step h3 {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  color: var(--gold-soft);
  letter-spacing: 0.02em;
}

.page-about .about-flow__step p {
  margin: 8px 0 0;
  max-width: 34em;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-flow__figure {
  margin: 0;
}

.page-about .about-flow__figure .figure__frame {
  overflow: hidden;
  border-radius: var(--r-md);
  border: 1px solid var(--hair);
  background: var(--graphite);
}

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

.page-about .about-flow__figure .figure__cap {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--dim);
}

/* ---------- 界面版本对比 ---------- */

.page-about .about-editions {
  margin-top: 30px;
  display: grid;
  border-radius: var(--r-lg);
  border: 1px solid var(--hair);
  overflow: hidden;
  background: var(--ink-deep);
}

.page-about .about-editions__split {
  display: block;
  height: 2px;
  background: linear-gradient(90deg, var(--red), var(--gold) 48%, var(--jade));
}

.page-about .about-edition {
  padding: 28px 22px 30px;
  position: relative;
}

.page-about .about-edition--simplified {
  background: linear-gradient(160deg, rgba(200, 16, 46, 0.16), rgba(26, 26, 26, 0));
}

.page-about .about-edition--formal {
  background: linear-gradient(200deg, rgba(14, 124, 107, 0.18), rgba(26, 26, 26, 0));
}

.page-about .about-edition__badge {
  display: inline-block;
  margin: 0;
  padding: 5px 16px;
  border-radius: var(--r-pill);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.12em;
}

.page-about .about-edition--simplified .about-edition__badge {
  background: var(--red);
  color: var(--gold-soft);
}

.page-about .about-edition--formal .about-edition__badge {
  background: var(--jade);
  color: var(--bone);
}

.page-about .about-edition h3 {
  margin: 16px 0 0;
  font-size: clamp(18px, 2.2vw, 22px);
  font-weight: 700;
  line-height: 1.45;
  color: var(--bone);
}

.page-about .about-edition > p {
  margin: 12px 0 0;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--mist);
  max-width: 32em;
}

.page-about .about-edition__list {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-edition__list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  padding-top: 10px;
  border-top: 1px dashed var(--hair);
}

.page-about .about-edition__list span {
  flex: 0 0 62px;
  font-size: 12.5px;
  letter-spacing: 0.08em;
  color: var(--dim);
}

.page-about .about-edition__list strong {
  font-size: 14.5px;
  font-weight: 600;
  line-height: 1.6;
  color: var(--bone);
}

.page-about .about-edition:hover .about-edition__badge {
  box-shadow: 0 0 0 4px rgba(242, 193, 78, 0.16);
}

.page-about .about-editions__foot {
  margin: 18px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--dim);
  max-width: 40em;
}

/* ---------- 版本时间轴 ---------- */

.page-about .about-chips {
  margin: 30px 0 0;
  max-width: 340px;
}

.page-about .about-chips .figure__frame {
  overflow: hidden;
  border-radius: var(--r-lg);
  border: 1px solid var(--hair);
  background: var(--ink-deep);
}

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

.page-about .about-chips .figure__cap {
  margin-top: 10px;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--dim);
}

.page-about .about-versions {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 4px;
}

.page-about .about-version {
  display: grid;
  gap: 12px;
  padding: 22px 0;
  border-top: 1px solid var(--hair);
}

.page-about .about-version:last-child {
  border-bottom: 1px solid var(--hair);
}

.page-about .about-version__marker {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--gold);
  padding-left: 16px;
  position: relative;
}

.page-about .about-version__marker::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--gold);
  box-shadow: 0 0 0 3px rgba(242, 193, 78, 0.15);
}

.page-about .about-version--current .about-version__marker {
  color: var(--red);
}

.page-about .about-version--current .about-version__marker::before {
  background: var(--red);
  box-shadow: 0 0 0 4px rgba(200, 16, 46, 0.24);
}

.page-about .about-version__body h3 {
  margin: 0;
  font-size: clamp(18px, 2.3vw, 23px);
  font-weight: 700;
  line-height: 1.4;
  color: var(--bone);
}

.page-about .about-version__body > p {
  margin: 10px 0 0;
  max-width: 34em;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--mist);
}

.page-about .about-version__body .fold {
  margin-top: 16px;
}

.page-about .about-version__body .fold summary {
  font-size: 14px;
  color: var(--gold-soft);
}

.page-about .about-version__body .fold__body ul {
  margin: 12px 0 0;
  padding-left: 18px;
  display: grid;
  gap: 8px;
}

.page-about .about-version__body .fold__body li {
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 维护节奏 ---------- */

.page-about .about-cadence {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-cadence__item {
  padding: 20px 20px 22px;
  border-radius: var(--r-md);
  border: 1px solid var(--hair);
  background: var(--graphite);
  border-left: 3px solid var(--gold);
  transition: border-color 0.25s var(--ease), transform 0.25s var(--ease);
}

.page-about .about-cadence__item:hover {
  transform: translateY(-4px);
  border-color: var(--gold);
  border-left-color: var(--red);
}

.page-about .about-cadence__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .about-cadence__item strong {
  display: block;
  margin-top: 8px;
  font-size: 16.5px;
  font-weight: 700;
  color: var(--bone);
}

.page-about .about-cadence__item p {
  margin: 8px 0 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

/* ---------- 延伸入口 ---------- */

.page-about .about-next {
  padding-top: clamp(32px, 5vw, 52px);
  border-top: 1px solid var(--hair-strong);
}

.page-about .about-next__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--bone);
}

.page-about .about-next__list {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-next__list a {
  display: grid;
  gap: 4px;
  padding: 16px 20px;
  border-radius: var(--r-md);
  border: 1px solid var(--hair);
  background: rgba(42, 42, 48, 0.55);
  text-decoration: none;
  transition: transform 0.22s var(--ease), border-color 0.22s var(--ease), background 0.22s var(--ease);
}

.page-about .about-next__list a:hover,
.page-about .about-next__list a:focus-visible {
  transform: translateY(-4px);
  border-color: var(--gold);
  background: rgba(122, 10, 27, 0.32);
}

.page-about .about-next__label {
  font-size: 16px;
  font-weight: 700;
  color: var(--gold-soft);
}

.page-about .about-next__desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 焦点可见 ---------- */

.page-about a:focus-visible,
.page-about summary:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    max-width: none;
  }

  .page-about .about-team-card {
    flex: 0 0 52%;
  }

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

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

  .page-about .about-version {
    grid-template-columns: 130px minmax(0, 1fr);
    gap: 24px;
    align-items: start;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }

  .page-about .about-team {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    overflow: visible;
    padding: 4px 0 0;
    margin: 0;
    gap: 16px;
  }

  .page-about .about-team-card {
    flex: none;
  }

  .page-about .about-team__hint {
    display: none;
  }

  .page-about .about-flow__grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .about-flow__figure {
    position: sticky;
    top: 128px;
  }

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

  .page-about .about-editions__split {
    height: auto;
    width: 2px;
    background: linear-gradient(180deg, var(--red), var(--gold) 48%, var(--jade));
  }

  .page-about .about-edition {
    padding: 34px 28px 36px;
  }

  .page-about .about-versions {
    margin-top: 36px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-index {
    display: none;
  }

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

  .page-about .about-rail__inner {
    display: block;
    position: sticky;
    top: 128px;
  }

  .page-about .about-body__grid {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(30px, 4vw, 60px);
  }

  .page-about .about-rail__list {
    list-style: none;
    margin: 0;
    padding: 6px 0;
    position: relative;
  }

  .page-about .about-rail__list::before {
    content: "";
    position: absolute;
    left: 5px;
    top: 14px;
    bottom: 14px;
    width: 2px;
    border-radius: 2px;
    background: linear-gradient(180deg, var(--red), var(--gold) 52%, var(--jade));
    opacity: 0.55;
  }

  .page-about .about-rail__link {
    display: grid;
    grid-template-columns: 14px auto;
    align-items: center;
    gap: 4px 10px;
    padding: 13px 0;
    text-decoration: none;
    color: var(--mist);
  }

  .page-about .about-rail__dot {
    grid-row: span 2;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--ink);
    border: 2px solid var(--hair-strong);
    transition: background 0.22s var(--ease), border-color 0.22s var(--ease), box-shadow 0.22s var(--ease);
  }

  .page-about .about-rail__tag {
    font-family: var(--font-mono);
    font-size: 11.5px;
    letter-spacing: 0.14em;
    color: var(--dim);
  }

  .page-about .about-rail__name {
    grid-column: 2;
    font-size: 13px;
    letter-spacing: 0.06em;
  }

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

  .page-about .about-rail__link:hover .about-rail__dot,
  .page-about .about-rail__link:focus-visible .about-rail__dot {
    background: var(--gold);
    border-color: var(--gold-soft);
    box-shadow: 0 0 0 4px rgba(242, 193, 78, 0.16);
  }
}

@media (min-width: 1180px) {
  .page-about .about-next__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-chips {
    max-width: 380px;
  }
}