reduce body side margins on mobile to preserve readable width

Desktop margins are acceptable, but on small screens they consume too much of
the viewport and leave content unnecessarily constrained.

At <=767px, reduce body side margins from 10% to 3% so more width is available
for ordinary content.

This lowers avoidable wrapping and reduces the chance of horizontal overflow
triggered by overly narrow content area.

Author: ritorhymes

assets/sass/main.scss

@@ -79,6 +79,10 @@ div.feature-matrix {
   }
 }
 @media screen and (max-width: 767px) {
+  body {
+    margin-right: 3%;
+    margin-left: 3%;
+  }
   .tg {
     width: auto !important;
   }