Why is my third footer widget field bigger than the other two?

Some widgets (like Flickr widget) looks better on a larger widget field. So third widget field is bigger than the other two for these kinds of widgets;

Screenshot_1

If you want to change it;

1) Go to Appearance->Theme Settings->General

2) Copy paste the following code to the Custom header script field;

<style>
.first-clmn,.second-clmn,.third-clmn {
width:33.3333% !important;
}
@media only screen and (max-width:800px) {
.first-clmn, .second-clmn, .third-clmn {
width:100% !important;
}
}
</style>

Screenshot_2