:root { --p: #7c3aed; --bg: #0f0f1a; --fg: #e2e8f0; --card: #16213e; --br: #2d2d4e; }
  * { box-sizing: border-box; margin: 0; padding: 0; }
  body { font-family: 'Inter', system-ui, sans-serif; background: var(--bg); color: var(--fg); height: 100vh; overflow: hidden; display: flex; flex-direction: column; }
  
  header { background: #1a1a2e; padding: 0.75rem 1.5rem; border-bottom: 1px solid var(--br); display: flex; align-items: center; gap: 1rem; }
  header h1 { font-size: 1rem; color: #a78bfa; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; }
  
  #search-bar { flex: 1; position: relative; max-width: 500px; }
  #search-input { width: 100%; background: var(--bg); border: 1px solid var(--br); color: var(--fg); padding: 0.5rem 1rem; border-radius: 20px; font-size: 0.85rem; transition: border 0.3s; }
  #search-input:focus { outline: none; border-color: var(--p); box-shadow: 0 0 10px rgba(124, 58, 237, 0.2); }
  #search-results { position: absolute; top: 110%; left: 0; right: 0; background: var(--card); border: 1px solid var(--br); border-radius: 8px; z-index: 100; display: none; max-height: 400px; overflow-y: auto; box-shadow: 0 10px 25px rgba(0,0,0,0.5); }
  .search-group { padding: 0.5rem; }
  .search-group h4 { font-size: 0.7rem; color: #64748b; margin: 0.5rem; text-transform: uppercase; }
  .search-item { padding: 0.5rem 1rem; font-size: 0.85rem; cursor: pointer; border-radius: 4px; }
  .search-item:hover { background: var(--br); }

  #session-info { background: #1a1a2e77; padding: 0.4rem 1.5rem; font-size: 0.75rem; color: #64748b; border-bottom: 1px solid var(--br); display: flex; gap: 1rem; align-items: center; }
  #status-dot { width: 8px; height: 8px; border-radius: 50%; background: #ef4444; }
  
  main { flex: 1; display: flex; overflow: hidden; }
  #sidebar { width: 260px; background: #1a1a2e; border-right: 1px solid var(--br); display: flex; flex-direction: column; }
  #sidebar h3 { padding: 1rem; font-size: 0.8rem; color: #64748b; text-transform: uppercase; }
  #session-list { flex: 1; overflow-y: auto; padding: 0.5rem; }
  .session-card { padding: 0.75rem; border-radius: 8px; cursor: pointer; margin-bottom: 0.5rem; transition: background 0.2s; border: 1px solid transparent; }
  .session-card:hover { background: var(--card); }
  .session-card.active { background: #1e1e3e; border-color: var(--p); }
  .session-card h5 { font-size: 0.85rem; margin-bottom: 0.2rem; }
  .session-card span { font-size: 0.7rem; color: #64748b; }

  #chat-container { flex: 1; display: flex; flex-direction: column; position: relative; }
  #messages { flex: 1; overflow-y: auto; padding: 2rem; display: flex; flex-direction: column; gap: 1.5rem; }
  .msg { max-width: 80%; padding: 0.8rem 1.2rem; border-radius: 16px; font-size: 0.95rem; line-height: 1.6; position: relative; animation: fadeIn 0.3s ease; }
  .msg div { white-space: pre-wrap; }
  @keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
  .msg.user { align-self: flex-end; background: linear-gradient(135deg, #7c3aed, #6d28d9); color: white; border-bottom-right-radius: 4px; }
  .msg.ai { align-self: flex-start; background: var(--card); border: 1px solid var(--br); border-bottom-left-radius: 4px; }
  .ref-tag { background: #7c3aed33; border: 1px solid var(--p); color: #c4b5fd; padding: 0.1rem 0.4rem; border-radius: 4px; font-size: 0.8rem; margin: 0 0.2rem; cursor: pointer; }

  #stt-draft { display: none; }

  #input-bar { background: #1a1a2e; padding: 1.25rem 2rem; border-top: 1px solid var(--br); display: flex; gap: 1rem; align-items: center; }
  #msg-input { flex: 1; background: var(--bg); border: 1px solid var(--br); color: var(--fg); padding: 0.75rem 1.25rem; border-radius: 24px; font-size: 0.95rem; resize: none; transition: 0.3s; }
  #msg-input:focus { outline: none; border-color: var(--p); }
  #msg-input.stt-active { border-color: #a78bfa; color: #a78bfa; font-style: italic; }
  
  .c-btn { width: 44px; height: 44px; border-radius: 50%; border: none; display: flex; align-items: center; justify-content: center; cursor: pointer; transition: 0.3s; }
  #send-btn { background: var(--p); color: white; }
  #mic-btn { background: #1e293b; color: #94a3b8; border: 1px solid var(--br); }
  #mic-btn.active { background: #ef4444; color: white; border-color: #ef4444; box-shadow: 0 0 15px rgba(239, 68, 68, 0.4); animation: pulse 1.5s infinite; }
  @keyframes pulse { 0% { transform: scale(1); } 50% { transform: scale(1.1); } 100% { transform: scale(1); } }
  
  #detail-overlay { position: fixed; top: 0; left: 0; right: 0; bottom: 0; background: rgba(0,0,0,0.8); backdrop-filter: blur(4px); z-index: 200; display: none; align-items: center; justify-content: center; }
  .detail-card { background: var(--card); border: 1px solid var(--br); width: 600px; max-width: 90%; max-height: 80%; overflow-y: auto; border-radius: 12px; padding: 2rem; position: relative; }
  .detail-card h2 { color: #a78bfa; margin-bottom: 1rem; }
  .tree-node { margin-left: 1.5rem; border-left: 1px dashed #2d2d4e; padding-left: 1rem; margin-top: 0.5rem; }
  .tree-label { font-size: 0.9rem; padding: 0.3rem 0; color: #94a3b8; }
  .close-btn { position: absolute; top: 1rem; right: 1rem; cursor: pointer; opacity: 0.5; }
  .close-btn:hover { opacity: 1; }
  
  /* Tabs */
  .tabs { display: flex; background: #1a1a2e; border-bottom: 1px solid var(--br); }
  .tab-btn { flex: 1; padding: 0.75rem; background: none; border: none; color: #64748b; font-size: 0.85rem; font-weight: 600; cursor: pointer; transition: 0.2s; }
  .tab-btn:hover { color: var(--fg); background: rgba(255,255,255,0.02); }
  .tab-btn.active { color: var(--p); border-bottom: 2px solid var(--p); background: rgba(124, 58, 237, 0.05); }
  
  .tab-content { display: none; flex-direction: column; flex: 1; overflow-y: auto; padding: 0.5rem; }
  .tab-content.active { display: flex; }
  
  /* Forms */
  .form-group { margin-bottom: 1rem; padding: 0 0.5rem; }
  .form-group label { display: block; font-size: 0.75rem; color: #64748b; margin-bottom: 0.25rem; text-transform: uppercase; }
  .form-group input, .form-group select, .form-group textarea { width: 100%; background: var(--bg); border: 1px solid var(--br); color: var(--fg); padding: 0.5rem; border-radius: 6px; font-size: 0.85rem; font-family: inherit; }
  .form-group input:focus, .form-group select:focus, .form-group textarea:focus { outline: none; border-color: var(--p); }
  
  .submit-btn { margin: 0 0.5rem; background: var(--p); color: white; border: none; padding: 0.75rem; border-radius: 6px; font-size: 0.85rem; font-weight: 600; cursor: pointer; transition: 0.2s; }
  .submit-btn:hover { opacity: 0.9; }
  
  /* Checkpoints */
  .checkpoint-card { padding: 0.75rem; border-radius: 8px; border: 1px solid var(--br); margin-bottom: 0.5rem; background: rgba(255,255,255,0.01); }
  .checkpoint-card h5 { font-size: 0.85rem; margin-bottom: 0.2rem; color: #a78bfa; }
  .checkpoint-meta { font-size: 0.7rem; color: #64748b; margin-bottom: 0.5rem; display: flex; justify-content: space-between; }
  .checkpoint-status { font-weight: 600; text-transform: uppercase; }
  .checkpoint-status.not-started { color: #64748b; }
  .checkpoint-status.in-progress { color: #fbbf24; }
  .checkpoint-status.submitted { color: #3b82f6; }
  .checkpoint-actions { display: flex; gap: 0.5rem; }
  .checkpoint-btn { flex: 1; padding: 0.4rem; font-size: 0.75rem; border-radius: 4px; border: none; cursor: pointer; font-weight: 600; transition: 0.2s; }
  .checkpoint-btn.start { background: var(--p); color: white; }
  .checkpoint-btn.submit { background: #10b981; color: white; }