Use visibility instead of display to fix wobble

style.css

@@ -35,7 +35,7 @@ header {
       margin: 0;
       /* turn the menu into a dynamic one for highly vertical devices */
       @media (orientation: portrait) {
-        & li { display: none; transition: display 3s ease }
+        & li { transition: display 3s ease; visibility: collapse }
         /* TODO: try this
         transition: opacity 1s ease-out;
     opacity: 0;
@@ -45,8 +45,8 @@ header {
      opacity: 1;
     height: auto;
     */
-        & li.active { display: inherit }
-        &:hover li { display: block }
+        & li.active { visibility: inherit  }
+        &:hover li { visibility: initial }
       }
     }
   }