.page-about {
  background:
    radial-gradient(120% 70% at 82% -8%, rgba(30, 90, 138, 0.36), transparent 62%),
    linear-gradient(180deg, var(--sapphire) 0%, var(--abyss) 100%);
  color: var(--ink);
  overflow-x: hidden;
}

.page-about .about-crumb {
  padding-top: var(--gap-md);
  padding-bottom: var(--gap-xs);
}

/* ---------- 首屏框景 ---------- */
.page-about .about-hero {
  padding: var(--gap-md) 0 var(--gap-lg);
}

.page-about .about-hero__frame {
  position: relative;
  padding: clamp(28px, 5.4vw, 68px) clamp(20px, 4.4vw, 62px) clamp(26px, 4vw, 52px);
  background:
    radial-gradient(130% 100% at 8% 0%, rgba(127, 211, 232, 0.16), transparent 58%),
    linear-gradient(158deg, rgba(18, 59, 102, 0.78) 0%, rgba(7, 26, 51, 0.9) 72%);
  border: 1px solid var(--line);
  clip-path: polygon(0 26px, 26px 0, 100% 0, 100% calc(100% - 26px), calc(100% - 26px) 100%, 0 100%);
  overflow: hidden;
}

.page-about .about-hero__frame::after {
  content: "";
  position: absolute;
  right: -16%;
  bottom: -46%;
  width: 58%;
  aspect-ratio: 1 / 1;
  background: conic-gradient(from 208deg,
    rgba(232, 180, 92, 0.24),
    transparent 38%,
    rgba(76, 195, 138, 0.18) 66%,
    transparent 92%);
  filter: blur(34px);
  pointer-events: none;
}

.page-about .about-hero__frame > * {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__title {
  margin: var(--gap-sm) 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2rem, 6.4vw, 4.2rem);
  line-height: 1.16;
  letter-spacing: 0.01em;
  max-width: 18ch;
  background: linear-gradient(104deg, var(--moon) 22%, var(--prism) 62%, var(--amber) 96%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.page-about .about-hero__lead {
  margin: var(--gap-md) 0 0;
  max-width: 62ch;
  font-size: clamp(0.98rem, 2.5vw, 1.1rem);
  line-height: 1.85;
  color: var(--ink-soft);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-sm);
  margin-top: var(--gap-md);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: var(--gap-lg) 0 0;
  padding: var(--gap-md) 0 0;
  border-top: 1px solid var(--line-soft);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--gap-sm) var(--gap-md);
}

.page-about .about-hero__fact {
  display: flex;
  flex-direction: column;
  gap: 2px;
  font-size: 0.82rem;
  color: var(--ink-faint);
  letter-spacing: 0.04em;
}

.page-about .about-hero__fact .mono {
  font-size: 1.32rem;
  font-weight: 600;
  color: var(--amber);
  letter-spacing: 0.02em;
}

/* ---------- 章节目录 ---------- */
.page-about .about-outline {
  display: flex;
  gap: var(--gap-xs);
  margin: 0 0 var(--gap-lg);
  padding: var(--gap-xs) 0 var(--gap-sm);
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
  overflow-x: auto;
  scrollbar-width: none;
}

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

.page-about .about-outline__link {
  flex: 0 0 auto;
  padding: 6px 2px;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-outline__link:hover,
.page-about .about-outline__link:focus-visible,
.page-about .about-outline__link.is-active {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

/* ---------- 通用章节 ---------- */
.page-about .section {
  padding: var(--gap-xl) 0;
}

.page-about .section__title {
  margin: var(--gap-xs) 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4.4vw, 2.5rem);
  line-height: 1.3;
  color: var(--moon);
}

.page-about .section__lead {
  margin: var(--gap-sm) 0 0;
  max-width: 64ch;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--ink-soft);
}

/* ---------- 01 源流 ---------- */
.page-about .about-origin__grid {
  display: grid;
  gap: var(--gap-lg);
}

.page-about .about-origin__body {
  margin-top: var(--gap-md);
  display: grid;
  gap: var(--gap-sm);
  font-size: 0.98rem;
  line-height: 1.9;
  color: var(--ink-soft);
}

.page-about .about-origin__body p {
  margin: 0;
  padding-left: var(--gap-sm);
  border-left: 1px solid var(--line);
}

.page-about .about-origin__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-xs);
  margin-top: var(--gap-md);
}

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

.page-about .about-origin__figure .media-frame,
.page-about .about-team__figure .media-frame,
.page-about .about-timeline__figure .media-frame {
  border: 1px solid var(--line);
  overflow: hidden;
  display: block;
}

.page-about .about-origin__figure img,
.page-about .about-team__figure img,
.page-about .about-timeline__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .media-frame__caption {
  display: block;
  margin-top: var(--gap-xs);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
}

/* ---------- 02 时间线 ---------- */
.page-about .about-timeline-section {
  background:
    linear-gradient(180deg, rgba(3, 8, 18, 0) 0%, rgba(18, 59, 102, 0.28) 32%, rgba(3, 8, 18, 0) 100%);
}

.page-about .about-timeline {
  list-style: none;
  margin: var(--gap-lg) 0 0;
  padding: 0;
}

.page-about .about-timeline__item {
  position: relative;
  padding-left: 30px;
  padding-bottom: var(--gap-md);
}

.page-about .about-timeline__item:last-child {
  padding-bottom: 0;
}

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 12px;
  bottom: 0;
  width: 1px;
  background: linear-gradient(180deg, var(--line-strong), var(--line-soft));
}

.page-about .about-timeline__item:last-child::before {
  display: none;
}

.page-about .about-timeline__item::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 18px;
  width: 9px;
  height: 9px;
  background: var(--prussian);
  transform: rotate(45deg);
  box-shadow: 0 0 0 3px rgba(3, 8, 18, 0.9);
  transition: background var(--dur) var(--ease);
}

.page-about .about-timeline__item:nth-child(2)::after { background: var(--prism); }
.page-about .about-timeline__item:nth-child(3)::after { background: var(--garnet); }
.page-about .about-timeline__item:nth-child(4)::after { background: var(--amber); }
.page-about .about-timeline__item:nth-child(5)::after { background: var(--amber-deep); }

.page-about .about-timeline__year {
  display: block;
  margin: 0 0 6px;
  font-size: 0.86rem;
  letter-spacing: 0.12em;
  color: var(--ink-faint);
}

.page-about .about-timeline__card {
  padding: var(--gap-sm) var(--gap-sm) var(--gap-md);
  background: linear-gradient(150deg, rgba(18, 59, 102, 0.72), rgba(7, 26, 51, 0.82));
  border: 1px solid var(--line-soft);
  border-left: 2px solid var(--prussian);
  border-radius: var(--radius-s);
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .about-timeline__card:hover {
  border-left-color: var(--amber);
  transform: translateX(2px);
}

.page-about .about-timeline__name {
  margin: var(--gap-xs) 0 0;
  font-family: var(--font-display);
  font-size: 1.08rem;
  font-weight: 600;
  color: var(--moon);
}

.page-about .about-timeline__card p {
  margin: var(--gap-2xs) 0 0;
  font-size: 0.93rem;
  line-height: 1.85;
  color: var(--ink-soft);
}

.page-about .about-timeline__figure {
  margin: var(--gap-lg) 0 0;
}

/* ---------- 03 变更对照 ---------- */
.page-about .about-changelog__grid {
  display: grid;
  gap: var(--gap-lg);
  padding: clamp(22px, 4vw, 44px) clamp(18px, 3.4vw, 40px);
  background:
    linear-gradient(200deg, rgba(232, 180, 92, 0.1) 0%, rgba(7, 26, 51, 0.9) 46%),
    rgba(3, 8, 18, 0.5);
  border: 1px solid rgba(232, 180, 92, 0.28);
  border-radius: var(--radius-m);
}

.page-about .about-changelog__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-sm);
  margin-top: var(--gap-md);
}

.page-about .about-changelog__folds {
  display: grid;
  gap: var(--gap-xs);
}

.page-about .about-fold {
  background: rgba(3, 8, 18, 0.42);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-s);
}

.page-about .about-fold[open] {
  border-color: rgba(232, 180, 92, 0.42);
}

.page-about .about-fold__sum {
  display: flex;
  align-items: baseline;
  gap: var(--gap-xs);
  padding: var(--gap-sm) var(--gap-sm);
  list-style: none;
  cursor: pointer;
  font-size: 0.96rem;
  font-weight: 600;
  color: var(--moon);
  letter-spacing: 0.01em;
}

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

.page-about .about-fold__sum::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  color: var(--amber);
  font-weight: 400;
}

.page-about .about-fold[open] .about-fold__sum::after {
  content: "–";
}

.page-about .about-fold__sum:focus-visible {
  outline: 1px solid var(--prism);
  outline-offset: -2px;
}

.page-about .about-fold__no {
  font-size: 0.74rem;
  color: var(--amber);
  letter-spacing: 0.1em;
}

.page-about .about-fold__body {
  padding: 0 var(--gap-sm) var(--gap-sm);
}

.page-about .about-fold__body p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.85;
  color: var(--ink-soft);
}

/* ---------- 04 团队 ---------- */
.page-about .about-team__grid {
  display: grid;
  gap: var(--gap-lg);
  margin-top: var(--gap-lg);
}

.page-about .about-team__stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .about-team__stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: var(--gap-sm);
  background: linear-gradient(160deg, rgba(18, 59, 102, 0.6), rgba(7, 26, 51, 0.9));
}

.page-about .about-team__num {
  font-size: clamp(1.5rem, 4vw, 1.95rem);
  font-weight: 600;
  color: var(--amber);
  line-height: 1.1;
}

.page-about .about-team__label {
  font-size: 0.86rem;
  color: var(--moon);
}

.page-about .about-team__note {
  font-size: 0.76rem;
  line-height: 1.65;
  color: var(--ink-faint);
}

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

.page-about .about-team__standards {
  margin-top: var(--gap-lg);
  padding: var(--gap-md) 0 0;
  border-top: 1px solid var(--line);
}

.page-about .about-team__subtitle {
  margin: 0 0 var(--gap-sm);
  font-family: var(--font-display);
  font-size: 1.14rem;
  font-weight: 600;
  color: var(--moon);
}

.page-about .about-team__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--gap-sm);
}

.page-about .about-team__list li {
  position: relative;
  padding-left: 22px;
  font-size: 0.94rem;
  line-height: 1.85;
  color: var(--ink-soft);
}

.page-about .about-team__list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 0.72em;
  width: 8px;
  height: 8px;
  background: var(--garnet);
  transform: rotate(45deg);
  opacity: 0.85;
}

/* ---------- 05 生态 ---------- */
.page-about .about-eco__grid {
  display: grid;
  gap: var(--gap-lg);
}

.page-about .about-eco__body {
  margin-top: var(--gap-md);
  display: grid;
  gap: var(--gap-sm);
  font-size: 0.96rem;
  line-height: 1.9;
  color: var(--ink-soft);
}

.page-about .about-eco__body p {
  margin: 0;
}

.page-about .about-eco__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-sm);
  margin-top: var(--gap-md);
}

.page-about .about-eco__aside {
  padding: var(--gap-md) var(--gap-sm);
  background: linear-gradient(170deg, rgba(30, 90, 138, 0.32), rgba(3, 8, 18, 0.72));
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
}

.page-about .about-eco__subtitle {
  margin: 0 0 var(--gap-sm);
  font-family: var(--font-display);
  font-size: 1.06rem;
  font-weight: 600;
  color: var(--moon);
}

.page-about .about-eco__dirs {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--gap-xs);
}

.page-about .about-eco__dir {
  display: grid;
  grid-template-columns: 24px minmax(0, 1fr);
  grid-template-areas:
    "no name"
    "no note";
  column-gap: var(--gap-xs);
  padding-bottom: var(--gap-xs);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-eco__dir:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-eco__dirno {
  grid-area: no;
  font-size: 0.78rem;
  color: var(--prism);
  letter-spacing: 0.08em;
  padding-top: 3px;
}

.page-about .about-eco__dirname {
  grid-area: name;
  font-size: 0.94rem;
  font-weight: 600;
  color: var(--moon);
}

.page-about .about-eco__dirnote {
  grid-area: note;
  font-size: 0.8rem;
  line-height: 1.7;
  color: var(--ink-faint);
}

.page-about .about-eco__aside-note {
  margin: var(--gap-sm) 0 0;
  padding-top: var(--gap-sm);
  border-top: 1px dashed var(--line-soft);
  font-size: 0.8rem;
  line-height: 1.75;
  color: var(--ink-faint);
}

/* ---------- 收尾行动 ---------- */
.page-about .about-cta {
  padding: 0 0 var(--gap-2xl);
}

.page-about .about-cta__inner {
  position: relative;
  padding: clamp(28px, 5vw, 58px) clamp(20px, 4vw, 56px);
  background:
    radial-gradient(100% 130% at 88% 0%, rgba(127, 211, 232, 0.2), transparent 62%),
    linear-gradient(140deg, rgba(18, 59, 102, 0.82), rgba(3, 8, 18, 0.94));
  border: 1px solid var(--line-strong);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
}

.page-about .about-cta__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 3.6vw, 2.05rem);
  line-height: 1.35;
  color: var(--moon);
}

.page-about .about-cta__lead {
  margin: var(--gap-sm) 0 0;
  max-width: 56ch;
  font-size: 0.96rem;
  line-height: 1.85;
  color: var(--ink-soft);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-sm);
  margin-top: var(--gap-md);
}

/* ---------- 显现动效 ---------- */
.page-about [data-reveal] {
  transition: opacity var(--dur-slow) var(--ease), transform var(--dur-slow) var(--ease);
}

.page-about .js-reveal [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
}

.page-about .js-reveal [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal],
  .page-about .about-timeline__card,
  .page-about .about-outline__link {
    transition: none;
  }
  .page-about .js-reveal [data-reveal] {
    opacity: 1;
    transform: none;
  }
}

/* ---------- 平板及以上 ---------- */
@media (min-width: 760px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-outline {
    gap: var(--gap-md);
    overflow-x: visible;
  }

  .page-about .about-origin__grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 0.9fr);
    align-items: start;
    gap: var(--gap-xl);
  }

  .page-about .about-origin__figure {
    margin-top: var(--gap-lg);
  }

  .page-about .about-timeline__item {
    display: grid;
    grid-template-columns: 68px minmax(0, 1fr);
    column-gap: 36px;
    padding-left: 0;
    padding-bottom: var(--gap-lg);
  }

  .page-about .about-timeline__item::before {
    left: 85px;
    top: 14px;
  }

  .page-about .about-timeline__item::after {
    left: 81px;
    top: 22px;
  }

  .page-about .about-timeline__year {
    text-align: right;
    padding-top: 4px;
    margin: 0;
  }

  .page-about .about-changelog__grid {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.25fr);
    align-items: start;
    gap: var(--gap-xl);
  }

  .page-about .about-team__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: stretch;
    gap: var(--gap-lg);
  }

  .page-about .about-team__figure {
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
  }

  .page-about .about-team__figure .media-frame {
    flex: 1 1 auto;
  }

  .page-about .about-team__standards {
    margin-top: var(--gap-xl);
  }

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

  .page-about .about-eco__grid {
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 0.8fr);
    align-items: start;
    gap: var(--gap-xl);
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 1040px) {
  .page-about .about-hero {
    padding: var(--gap-lg) 0 var(--gap-xl);
  }

  .page-about .about-hero__lead {
    max-width: 58ch;
  }

  .page-about .section {
    padding: var(--gap-2xl) 0;
  }

  .page-about .about-timeline {
    margin-top: var(--gap-xl);
  }

  .page-about .about-timeline__card {
    padding: var(--gap-md) var(--gap-md) var(--gap-md) var(--gap-md);
  }

  .page-about .about-changelog__grid {
    padding: clamp(34px, 4.4vw, 62px) clamp(30px, 4vw, 62px);
  }

  .page-about .about-eco__aside {
    padding: var(--gap-md);
  }
}