add a little margin to the bottom of the examples

docs/assets/css/docs.css

@@ -554,6 +554,9 @@ body {
   margin-top: 30px;
 }
 
+.example-wrap {
+  margin-bottom: 30px;
+}
 .example-wrap .example {
   display: block;
   overflow: hidden;

sass/docs.scss

@@ -581,6 +581,8 @@ body {
   margin-top: 30px;
 }
 .example-wrap {
+  margin-bottom: 30px;
+
   .example {
     display: block;
     overflow: hidden;