.meu-login{
    background: url('https://pbs.twimg.com/media/Ft28lB2WIAEZxPG?format=jpg&name=large') no-repeat center center fixed !important; 
    -webkit-background-size: cover  !important;
    -moz-background-size: cover  !important;
    -o-background-size: cover  !important;
    background-size: cover  !important;
}