Add borders to elements

Note: below are the class options for adding borders to any element. The thin borders are 1 px in width and the others are 2px in width. They are both gray in color. You can see each of the border classes here, Examples.

<div class="top-border"> </div>
<div class="bottom-border"> </div>
<div class="left-border"> </div>
<div class="right-border"> </div>
<div class="top-thin-border"> </div>
<div class="bottom-thin-border"> </div>
<div class="left-thin-border"> </div>
<div class="right-thin-border"> </div>
<div class="all-border-thin"> </div>
<div class="all-border-thick"> </div>