Remove padding around inner frame (#3605)

This leads to weird spacing at the bottom of the page, and generally the docs look better with this padding removed on all sides.

Author: Hixie

lib/resources/styles.css

@@ -164,7 +164,6 @@ main {
   flex: 1;
   display: flex;
   flex-direction: row;
-  padding: 20px;
   min-height: 0;
 }
 
@@ -1197,4 +1196,4 @@ li.inherited a {
   a[href]:after {
    content: "" !important;
   }
-}
+}