CSS Absolute Positioning Auto+Pixels

So I'm trying to absolute position something and using the left property as auto, I can get it to stay in the same spot in each size window, but then I want it to go about 7 pixels further to the left, but keep in the "auto range", so say it computes the auto as a left of 340 pixels, and then i need the left to be 350, if i just used 357px, then when somebody had a bigger browser it would be need to be computed as say 367px (360px auto), is there any way to do this "calculating"?

I'm not really sure exactly what you want but if you want things to stay in the same positions for different screen resolutions you can do this:

Code:

---

whatever
{
position: absolute;
left: 50%;
margin-left: x;
width: x;
height: x;
}

---

Just change the value of margin-left until it's in the right position. It will be in the same position for all screen resolutions.