Issue in the width of a fixed positioned div - html

Question

How to make a fixed positioned div fit its content width?
I've made a demo here
Before clicking on the Load button, the div must only have enough width to contain the gif image and the button.
When more content is loaded, the width of the div must fit its width.
here is the CSS I've made
body{background: #eee; }
#divToCenter{
border-radius: 5px;
box-shadow: 0 0 0 10px rgba(0,0,0,0.2);
background: #fff;
padding: 20px;
position: fixed;
top: 20px;
right: 0;
left: 0;
margin-right: auto;
margin-left: auto;
max-width: 400px;
}

Answer 1

Since you are using JavaScript/jQuery to show/hide the loader, why don't you change the width of the box via JavaScript?
You could simply toggle a class called .wide for instance, to achieve the desired result as follows:
EXAMPLE HERE
CSS:
#divToCenter{
/* other declarations... */
text-align: center;
width: 50px;
}
#divToCenter.wide {
width: 400px;
text-align: left;
}
jQuery:
var $divToCenter = $("#divToCenter");
$("#show-more-data").click(function() {
// ...
$divToCenter.addClass("wide");
});
$("#show-less-data").click(function() {
// ...
$divToCenter.removeClass("wide");
});

Answer 2

Add display: table, position: relative and margin:0 auto to the following element:
#divToCenter{
border-radius: 5px;
box-shadow: 0 0 0 10px rgba(0,0,0,0.2);
background: #fff;
padding: 20px;
display: table;/*Add this*/
position: relative;/*Change fixed with relative*/
top: 20px;
margin:0 auto;/*Add this*/
max-width: 400px;
}
fiddle