Fix: Tabs' contents' top margin

Before this change, the images in the div.grid-container were
displayed about one line higher than the text in the adjacent
paragraph.

assets/css/tabs.scss

@@ -20,6 +20,14 @@ table td, table th {
 
     & .tabs div li {
         display: inline;
+
+        & .grid-container {
+            margin-top: 1em;
+
+            & p {
+                margin-top: 0em;
+            }
+        }
     }
 }