Custom WP Login Screen and Background

<?php

/**
 * A new logo for the admin area and an own background color 
 * @author Andreas Hecht
 */
function ah_login_logo() { 
?>
 <style type="text/css">
 #login h1 a, .login h1 a {
 background-image: url(<?php echo get_stylesheet_directory_uri(); ?>/images/dein-logo.png);
 margin-bottom: 0;
 background-size: 180px;
 height: 180px;
 width: 180px;
 margin-left: auto;
 margin-right: auto;
 border-radius: 50%;
 }
 body.login {background-color: #0073bf;} .login #backtoblog a, .login #nav a {color: #fff !important}
 </style>
<?php }
add_action( 'login_enqueue_scripts', 'ah_login_logo' );