responsive mashup resolution problem

I have created a responsive mashup(second layout).

I created the mashup using 1024 x 768

The problem appears when i try to open the same responsive mashup in a screen with a different resolution (1366 x 768).

In that case,the contents of the screen becomes left aligned and a lot of white space appears on the right side of the screen .

Please suggest a solution to the above mentioned problem.

Thanks and regards,

Saurabh