:root {
  --a0004-bg1: #fdf7ff;
  --a0004-bg2: #f4fbff;
  --a0004-accent: #7c3aed;
}

body.theme-a0004 {
  background: radial-gradient(900px 500px at 80% 0%, rgba(124,58,237,.22), transparent 60%),
              radial-gradient(900px 500px at 10% 10%, rgba(236,72,153,.18), transparent 55%),
              linear-gradient(180deg, var(--a0004-bg1), var(--a0004-bg2));
  padding-bottom: 72px;
}

.hero {
  position: sticky;
  top: 0;
  z-index: 5;
  backdrop-filter: blur(10px);
  background: rgba(255,255,255,.65);
  border-bottom: 1px solid rgba(0,0,0,.06);
}

.hero-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: .75rem 1rem;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1rem;
  align-items: center;
}

.logo-dual a {
  text-decoration: none;
  color: var(--a0004-accent);
  font-weight: 800;
}

.timeline-shell {
  max-width: 1100px;
  margin: 1rem auto 2rem;
  padding: 0 1rem;
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 1rem;
}

@media (max-width: 960px) {
  .timeline-shell { grid-template-columns: 1fr; }
  .toc { order: 2; }
}

.toc {
  position: sticky;
  top: 88px;
  align-self: start;
  background: rgba(255,255,255,.7);
  border: 1px solid rgba(0,0,0,.06);
  border-radius: 1rem;
  padding: .75rem;
}

.toc a {
  display: block;
  padding: .35rem .5rem;
  border-radius: .6rem;
  text-decoration: none;
}

.toc a.active {
  background: rgba(124,58,237,.14);
  color: var(--a0004-accent);
}

.timeline {
  position: relative;
  background: rgba(255,255,255,.75);
  border: 1px solid rgba(0,0,0,.06);
  border-radius: 1rem;
  padding: 1rem;
}

.timeline-line {
  position: absolute;
  left: 18px;
  top: 16px;
  bottom: 16px;
  width: 3px;
  background: linear-gradient(180deg, rgba(124,58,237,.0), rgba(124,58,237,.55), rgba(236,72,153,.35));
  border-radius: 999px;
}

.timeline-item {
  position: relative;
  padding-left: 2.5rem;
}

.timeline-item:before {
  content: "";
  position: absolute;
  left: 9px;
  top: .9rem;
  width: 18px;
  height: 18px;
  border-radius: 999px;
  background: #fff;
  border: 3px solid rgba(124,58,237,.7);
}

.tabbar {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  display: flex;
  gap: .25rem;
  padding: .5rem;
  background: rgba(255,255,255,.82);
  border-top: 1px solid rgba(0,0,0,.06);
  backdrop-filter: blur(10px);
}

.tabbar .tab {
  flex: 1;
  text-align: center;
  padding: .5rem;
  border-radius: .75rem;
  text-decoration: none;
}

.tabbar .tab.active {
  background: rgba(124,58,237,.14);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

#footer {
  padding: 1.5rem 0;
  border-top: 1px solid rgba(0,0,0,.08);
  background: rgba(255,255,255,.6);
}