Remove unnecessary fix for focus outlines in Firefox

Author: jonathantneal

evergreen.css

@@ -286,23 +286,6 @@
   font: inherit; /* 2 */
 }
 
-/**
- * Remove the inner border and padding of focus outlines in Firefox.
- */
-
-::-moz-focus-inner {
-  border-style: none;
-  padding: 0;
-}
-
-/**
- * Restore the focus outline styles unset by the previous rule in Firefox.
- */
-
-:-moz-focusring {
-  outline: 1px dotted ButtonText;
-}
-
 /* Interactive
  * ========================================================================== */