body.gpt-builder {
  font-family: system-ui, -apple-system, sans-serif;
  background: radial-gradient(circle at top, #0b1120, #020617);
  color: #e5e7eb;
  height: 100vh;
  margin: 0;
  overflow: hidden;
}

#ragApp {
  display: grid;
  grid-template-columns: 340px 1fr;
  height: calc(100vh - 52px);
}

.rag-tree-panel {
  padding: 16px;
  background: #020617;
  border-right: 1px solid #334155;
  overflow-y: auto;
}

.rag-tree-item {
  padding: 14px;
  margin-bottom: 10px;
  background: rgba(30,64,175,0.25);
  border: 1px solid #3b82f6;
  border-radius: 12px;
  cursor: pointer;
}

.rag-tree-item:hover {
  background: rgba(59,130,246,0.35);
}

.chat-messages {
  flex: 1;
  padding: 20px;
  overflow-y: auto;
  background: #0f172a;
}

.chat-bubble {
  margin-bottom: 16px;
  display: flex;
}

.chat-user { justify-content: flex-end; }
.chat-bot  { justify-content: flex-start; }

.chat-bubble-inner {
  max-width: 78%;
  padding: 12px 16px;
  border-radius: 18px;
  font-size: 14.5px;
}

.chat-user .chat-bubble-inner { background: #2563eb; color: white; }
.chat-bot  .chat-bubble-inner { background: #1e2937; border: 1px solid #475569; }

#chatInputRow {
  padding: 16px;
  background: #0f172a;
  border-top: 1px solid #334155;
}

.demo-banner {
  background: linear-gradient(90deg, #1e40af, #3b82f6);
  color: white;
  padding: 10px;
  font-weight: 600;
}