Move error color to theme

css/_variables.scss

 //buttons
 $linkFontColor: #489afe;
 $linkHoverFontColor: #287ade;
-$errorColor: #c61600;
+

css/themes/_light.scss

 $linkFontColor: #3572b0;
 $linkHoverFontColor: darken(#3572b0, 10%);
 $dropdownColor: #333;
+$errorColor: #c61600;
 
 // Popover colors
 $popoverBg: #000;