last commit claimed to have fixed the masthead overflow into the container-fluid div, but this was not the case.  This commit addresses the underlying cause of the overflow and fixes the margins.  In particular, the styling for #masthead had padding: 5px which caused the overflow.  To keep the padding and prevent the overflow, I added width: calc(100% - 10px) to the #masthead styling.  I also removed padding: 0px; since this was overridden by padding: 5px;