I bought a ready html template including some css code. All works fine. But now I want add a div laver which should be positioned relative to another div element which position is calculated by css code. No problem to find the correct coordinates. But that only works for a given browser resolution. Please have a look to the attached 2 screenshots. On screenshot1 you can see a white square in the middle. This one is positioned by css. The yellow squre right from the white square is the layer I placed later. If shall touch the frame of the white square to be side by side. This screenshot was taken at a display solution of 1440x900. On screenshot2 you see the same site at 1920*1080 display solution. In the attached zip file you find all html/js/css files you need. Important for you are only the two files [url removed, login to view] and css/style.css.
I think it is clear what I need: a css code for a div layer so that it can be positioned relative to the white div square, independing from the display resolution.