fixed lastversion btn design

src/css/index.styl

@@ -25,6 +25,9 @@ btnState()
       btnState()
       border-color darkHtmlColor
       box-shadow none
+  &__lastversionbtn
+    & > i
+      font-size 20px
   .optionicon
     &:hover, &:focus, &:active
       color htmlColor