title: Flexbox child : any way to reset "display: none"?
body: <p>Typically I set lengthy menus on my mobile site to an initial <code>display: none</code> and use a <code>Javascript</code> "Expand" button to switch them back to <code>display: flex</code> (or whatever).</p>
  
  <p>But this time around, I can't hide the flex parent. I have to hide only certain flex children, because certain others must be visible. But without a <code>display: flex-child</code> to switch back to...</p>
  
  <p>Is there a solution?</p>