.demos-shell {
  padding: 140px 7vw 100px;
  background: var(--canvas);
  min-height: 100vh;
}
.demos-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 32px;
  max-width: 1320px;
  margin: 0 auto;
}
.demos-tree {
  background: var(--card);
  border: 1px solid var(--card-line);
  border-radius: var(--radius-md);
  padding: 24px;
  height: fit-content;
  position: sticky;
  top: 100px;
}
.demos-tree h3 {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.28em;
  color: var(--mute);
  margin-bottom: 18px;
  text-transform: uppercase;
}
.tree-section { margin-bottom: 18px; }
.tree-section-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 13px;
  color: var(--headline);
  font-weight: 600;
  cursor: pointer;
}
.tree-section-header:hover { background: var(--canvas-soft); }
.tree-items {
  margin-left: 16px;
  display: grid;
  gap: 2px;
  padding-top: 4px;
}
.tree-item {
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 13px;
  color: var(--mute);
  cursor: pointer;
  font-weight: 500;
}
.tree-item:hover { background: var(--canvas-soft); color: var(--headline); }
.tree-item.active { background: var(--accent-soft); color: var(--accent-base); font-weight: 600; }

.demo-panel {
  background: var(--card);
  border: 1px solid var(--card-line);
  border-radius: var(--radius-md);
  padding: 56px;
  min-height: 640px;
  position: relative;
  overflow: hidden;
}
.demo-panel::before {
  content: ""; position: absolute;
  inset: -50% -10% auto auto;
  width: 320px; height: 320px;
  background: radial-gradient(circle, var(--accent-soft), transparent 70%);
  filter: blur(20px);
}
.demo-panel > * { position: relative; }
.demo-panel h2 {
  font-family: var(--display);
  font-size: clamp(28px, 3.4vw, 44px);
  font-weight: 300;
  color: var(--headline);
  margin-bottom: 16px;
  letter-spacing: -0.005em;
}
.demo-panel p {
  color: var(--body);
  font-weight: 400;
  line-height: 1.65;
  max-width: 62ch;
  font-size: 16px;
}

@media (max-width: 900px) {
  .demos-layout { grid-template-columns: 1fr; }
  .demos-tree { position: static; }
  .demo-panel { padding: 32px; min-height: 400px; }
}