baseof: use dir attribute instead of class

and set default dir to `auto`

main(css): rm unused class

assets/css/main.css

@@ -52,14 +52,6 @@
     width: 26px;
 }
 
-.direction-rtl {
-    direction: rtl;
-}
-
-.direction-ltr {
-    direction: ltr;
-}
-
 code {
     direction: ltr;
 }