If you want to center align a div in a page, it can be achieved by putting the div inside another div (for example, by creating a new outer div.) And then, applying the following css code snippet will align the inner div in center.
#out { width: 100%; text-align: center; }
#in { display: inline-block; }
For example, for the following html code:
<div class="out"> <div class="in"> <div> </div>
as shown in the figure below, the inner div is aligned in center when the following css code is used.