Are my webpages responsive ?

I have 4 very (very very) simple div-based webpages that differ from each other only by the position of a "textbox". I insist : the 4 pages are the SAME but for the position of the "textbox". It's not 4 different pages ; the code is the same, but the CSS that is used to positioned the box. See the model at : [login to view URL] They have a background, a "textbox", few lines of text and links below. That's all. They use HTML, CSS, ready-made JavaScript and jQuery scripts (the only goal of this is "displaying a special image" inside the page - I won't tell more about it now as projects here can be seen by anybody, and I don't like that...). They have about 40 lines of code. I need to know whether or not they are responsive. If they're not, you will have to create responsive pages, if possible, or create the best solution possible. I need to have these pages look approximately the same on different browsers, browser versions, operating systems, screen resolutions and devices (desktop computer, mobile phones, tablets).