Typo in class attributes for About section

[ramesh-tr]

There are some typo in the about section

<div class="item col-mg-4 col-sm-4 col-sm-12">

There is no such class 'col-mg' in bootstrap, nor it's defined in the styles.css. I think this should be col-md.

Also, there are two definitions col-sm-4 and col-sm-12 for the same element, which will not produce correct behavior in different browsers.