/* Needs more specificity to override theming app */
body#body-login {
    background-color    : #777 !important;
    background-image    : url('https://source.unsplash.com/featured/?nature,nature') !important;
    background-position : center;
    background-repeat   : no-repeat;
    background-size     : cover;
}

#body-login input.primary,
#body-login button.primary,
#body-login #alternative-logins li a {
    background-color : rgba(0, 0, 0, .5) !important;
}