title: jupyter -toolbar is invisible
body: <p>I newly downloaded a jupyter and try to use it.
  However, with my mac and window computer, 
  I cannot see the toolbar in jupyter.</p>
  
  <p>I tried to search to solve this issue and I tried to uninstall every version of python on my computers, both on mac and window one, and reinstall the jupyter. </p>
  
  <p>However, I still see the same problem.
  Can someone help me do deal this issue? </p>
  
  <p>Thank you.</p>
  
  <p><img src="https://i.stack.imgur.com/X5Phy.png" alt="enter image description here"></p>