Personnaliser le logo de connexion de WordPress sans plugin

/* Custom Login Logo */
function wpc_custom_login_logo() {
	$custom_logo_url = get_stylesheet_directory_uri() . '/assets/img/wpchannel-logo.svg';
	$custom_logo_width = 260;
	$custom_logo_height = 130;

	if ($custom_logo_url) {
		echo
		'<style>
			h1 a{
				background-image:url("'.$custom_logo_url.'")!important;
				background-size:'.$custom_logo_width.'px '.$custom_logo_height.'px!important;
			}
			.login h1 a {
				height:'.$custom_logo_height.'px;
				width:'.$custom_logo_width.'px;
			} 
		</style>';
	}
}
add_action('login_head', 'wpc_custom_login_logo');

/* Custom Login CSS */
function wpc_login_css() {
	echo '<style>
	#backtoblog{display:none}#login{margin:0 auto;padding-top:2%;width:440px}#wp-submit.button-primary{background-color:#11d1e2;border-color:#11d1e2;border-radius:2rem;box-shadow: 5px 5px 0 #283765;color:#fff;font-family:brandon-grotesque,sans-serif;font-weight: 700;padding:1rem 2.8rem;text-transform:uppercase}.login #nav{display:none}.login .message{background-color:#333;border-color:#fff;color:#fff;margin-top:15px}.login form{background:none repeat scroll 0 0 #fff;border:none;border-radius:.5rem;box-shadow:none;margin-top:3rem;padding:2rem}.login form .input{-webkit-transition:border-color .15s ease-in-out,-webkit-box-shadow .15s ease-in-out;background-clip:padding-box;background-color:#f4f6fc;border:2px solid rgba(33,25,75,0.36);border-radius:.5rem;color:#333;display:block;font-size:1rem;font-weight:400;height:calc(1.5em   .75rem   4px);line-height:1.5;margin-top:.5rem;padding:.375rem .75rem;transition:border-color .15s ease-in-out,-webkit-box-shadow .15s ease-in-out;transition:border-color .15s ease-in-out,box-shadow .15s ease-in-out;transition:border-color .15s ease-in-out,box-shadow .15s ease-in-out,-webkit-box-shadow .15s ease-in-out;width:100%}.login form input:focus{border-color:#7debf5;box-shadow:0 0 0 .2rem rgba(17,209,226,0.25)}.login form input[type="checkbox"]{background-color:rgba(33,25,75,0.36);border:2px solid rgba(33,25,75,0.36)}.login h1 a{display:block;margin:0 auto;outline:0;overflow:hidden;text-indent:-9999px}.login input[type="text"]{background-color:#f4f6fc;border:2px solid rgba(33,25,75,0.36)}.login label{color:#6e799a;display:inline;font-weight:700;}.privacy-policy-page-link{display:none}.submit{margin:0;text-align:center}html{height:100%}body{background:linear-gradient(176deg, #6639e9 0%, #6639e9 450px,#f4f6fc 450px,#f4f6fc 100%) no-repeat}button.button-primary:hover{color:#000;text-shadow:none}div.error{display:none;visibility:hidden}div.updated{background-color:#333;border-color:#fff;color:#fff;margin-top:15px}input#wp-submit{-moz-user-select:none;-ms-user-select:none;-webkit-transition:all .2s cubic-bezier(0.165,0.84,0.44,1);-webkit-user-select:none;background-color:transparent;border:1px solid transparent;border-color:transparent;border-radius:0;display:inline-block;font-family:arimo,sans-serif;line-height:1.5;padding:.5rem 1.8rem;text-align:center;transition:all .2s cubic-bezier(0.165,0.84,0.44,1);user-select:none;vertical-align:middle}input#wp-submit:focus{background:none repeat scroll 0 0 transparent;border-color:#fff;border-width:2px;color:#FFF}input#wp-submit:hover{background-color:#0fb9c8;border-color: #11d1e2;box-shadow:none;color:#fff;transform: translateX(0.2rem) translateY(0.2rem)}input.button-primary:hover{color:#000;text-shadow:none}.dashicons-visibility::before{color:#fff}.dashicons-visibility::before{color:#333}.wp-pwd{position:relative}.wp-hide-pw{background:none;border:0;box-shadow: none;height: 90%;padding: .5rem 1rem;position:absolute;right:1%;top:5%}.user-pass-wrap{margin-bottom:1rem}</style>';
}
add_action('login_head', 'wpc_login_css');