Fix transition values

Author: francoispluchino

scss/_mixins.scss

@@ -8,7 +8,7 @@
 }
 
 @mixin transition($transition) {
-    -webkit-transition: $transition;
-    -o-transition: $transition;
-    transition: $transition;
+    -webkit-transition: #{$transition};
+    -o-transition: #{$transition};
+    transition: #{$transition};
 }