Add scroll padding for anchor links (#1214)

Author: xPaw

styles/theme-base.css

@@ -18,6 +18,7 @@
   --dark-magenta-color: #793862;
   --medium-magenta-color: #AE508D;
   --light-magenta-color: #CF82B1;
+  scroll-padding-top: 4rem;
 }
 
 .clearfix {