fix Menu bar shakes when swiping pages in Safari

src/theme/css/chrome.css

@@ -16,6 +16,7 @@ a > .hljs {
     body-container is necessary because mobile browsers don't seem to like
     overflow-x on the body tag when there is a <meta name="viewport"> tag.
 */
+@media only screen and (max-width: 420px) {
     #body-container {
         /*
             This is used when the sidebar pushes the body content off the side of
@@ -24,6 +25,7 @@ a > .hljs {
         */
         overflow-x: clip;
     }
+}
 
 /* Menu Bar */