Fix font color in code block(markdown preview)

Author: cJack1913

browser/components/markdown.styl

@@ -199,7 +199,6 @@ ol
   &>li>ul, &>li>ol
     margin 0
 code
-  color #CC305F
   padding 0.2em 0.4em
   background-color #f7f7f7
   border-radius 3px