* {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    html, body {
      height: 100%;
      font-family: Arial, sans-serif;
    }

    #TOP_PANEL {
      height: 50px;
      background: #333;
      color: white;
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0 10px;
    }

    #TOP_PANEL_LEFT_SIDE, #TOP_PANEL_RIGHT_SIDE {
      display: flex;
      align-items: center;
      gap: 10px;
    }

    #LEFT_PANEL {
      background: #f4f4f4;
      padding: 10px;
      width: 250px;
      flex-shrink: 0;
    }

    #CENTRAL_PANEL {
      flex: 1;
      display: flex;
      flex-direction: column;
      height: 100%;
    }

    #CENTRAL_PANEL_MAIN_AREA {
      flex: 1;
      overflow-y: auto;
      padding: 10px;
    }

    #CENTRAL_PANEL_BOTTOM_AREA {
      background: #f0f0f0;
      padding: 10px;
    }

    #USER_INPUT_AREA_ATTACHMENTS {
      margin-bottom: 5px;
      font-size: 12px;
      color: #444;
    }

    #USER_INPUT_AREA_DOCUMENT_AND_IMAGE_DROPZONE {
      border: 2px dashed #aaa;
      padding: 10px;
      margin-bottom: 10px;
      text-align: center;
    }

    #USER_INPUT_AREA_INPUT_FORM input[type="text"] {
      width: 100%;
      padding: 8px;
    }

    .conversation-bubble {
      max-width: 70%;
      margin: 5px 0;
      padding: 10px;
      border-radius: 8px;
    }

    #CENTRAL_PANEL_MAIN_AREA_CONVERSATION_HISTORY_USER {
      background: lightgreen;
      align-self: flex-end;
      text-align: right;
    }

    #CENTRAL_PANEL_MAIN_AREA_CONVERSATION_HISTORY_APP_RESPONSE {
      background: lightyellow;
      align-self: flex-start;
      text-align: left;
    }

    #APP_CONTAINER {
      display: flex;
      height: calc(100% - 50px);
    }

    #USER_INPUT_AREA button {
      margin: 5px 5px 0 0;
      padding: 8px 12px;
    }

    @media (max-width: 768px) {
      #APP_CONTAINER {
        flex-direction: column;
      }

      #LEFT_PANEL {
        width: 100%;
      }
    }