Full Screen Background on WP Login Page

The following function add full screen background on WP Login page

1. Open functions.php in your theme directory

2. Add this function to functions.php

// LOGIN - full background
function my_login_style() {
?>
<style type="text/css">
 body.login {
 background:url('https://yourwebsiteaddress.com/wp-content/uploads/wploginbg.jpg') no-repeat center center fixed;
 -webkit-background-size: cover;
 -moz-background-size: cover;
 -o-background-size: cover;
 background-size: cover;
 position:fixed;
 top:0;
 left:0;
 z-index:10;
 overflow: hidden;
 width: 100%;
 height:100%;
 }

</style>
<?php
}
add_action('login_head', 'my_login_style');
?>

3. Save