Use :focus-visible in the UA stylesheet

See w3c/csswg-drafts#4278.

Author: emilio

source

@@ -113051,7 +113051,7 @@ rt { display: ruby-text; }
 :link:active, :visited:active { color: #FF0000; }
 :link, :visited { text-decoration: underline; cursor: pointer; }
 
-:focus { outline: auto; }
+:focus-visible { outline: auto; }
 
 mark { background: yellow; color: black; } /* this color is just a suggestion and can be changed based on implementation feedback */