stephencottontail on "navigation wrapping to second line"

Your CSS rules in the @media query need to be contained in brackets like so:

@media screen and (min-width: 600px) {
    .main-navigation li:last-child {
        margin-right: 0;
    }

    .main-navigation ul.nav-menu, .main-navigation div.nav-menu > ul {
        padding-left: 10px;
    }
}