jQuery popup window

Custom popup window with on load and click events.

HTML

<div class="message">
    <div class="message_pad">
        <div id="message"></div>
        <div class="message_leave">
            
        </div>
    </div>
</div>

CSS

.message {
	display: none;
	position: absolute;
	top: 0;
	left: 0;
	width: 100%;
	height: 200px;
	background: #b2b2b2;
	opacity: 0.90;
	z-index: +1;
}
#message {
	width: 100%;
	height: 485px;
	font-size: 14px;
	overflow-y: scroll;
}
.message_leave {
	width: 100%;
	height: 15px;
	text-align: center;
	background: #f5f5f5;
	font-size: 10px;
}
.message_pad {
	position: fixed;
	left: 200px;
	margin-top: 65px;
	width: 500px;
	height: 500px;
	padding: 5px;
    color: #000000;
	background: #f5f5f5;
	border: 2px solid;
	border-color: #9a9a9a;
	border-radius: 10px;
	box-shadow: 0px 4px 15px #000000;
}

JavaScript

// Save data to sessionStorage
sessionStorage.setItem('firstVisit', '1');

/* Fix size on document ready.
*/
$(function()
{
    if (!sessionStorage.getItem('firstVisit') === "1")
    {
       $(".message").show(); 
    } 
    
    //Close element.
    $(".message").click(function()
    {
       $(this).hide();
    });
    
	$(".message").css({
		'height': $(document).height()+'px'
	});
    $(".message_pad").css({
        'left': ($(document).width()/2 - 500/2)+'px'
    });
});
/*
* Fix size on resize.
*/
$(window).resize(function(){
	$(".message").css({
		'height': $(document).height()+'px'
	});
    $(".message_pad").css({
        'left': ($(document).width()/2 - 500/2)+'px'
    });
});