The problem is that you used a table structure in your front page which is only responsive to a certain width. There is a way to make it responsive (sort of) which would require a theme update but what happens is that the table stays full width but you get scroll bars in your page (not very pretty).
The use of a table is incorrectly used in your page. To achieve the same result but responsive, is to make the top heading part as the Call to Action position and then your columns of content where each one is in a widget for positions, then choosing the appropriate page template too (one that has the widget positions needed, like the Top or Bottom positions.
Refer to the widget layouts here: http://demo.styledthemes.com/celestial-reloaded/widget-layout/
