Nav text unreadable on small view

[mreschke]

When you shrink your browser or view on mobile, open the nav menu on the left and the top BACK arrow and folder name are black, same as background so unreadable. Need to change md-nav to different color when shrink

@media only screen and (max-width: 76.1875em) {
    .md-nav {
        background-color: #eeeeee !important;
    }
}

[fmaida]

This issue should have been (hopefully) fixed in the latest commit.