HTML / CSS : Fixed Margin & Fluid Width

Question

How should I make this with CSS:

I would like to have 2 divs or more and their width should be in percent, but the margin between the divs should be fixed, in this example 30px

The problem for me is the margin between the two divs because I can put the divs into a bigger div and set left and right padding to 30px and thats ok, but what should I do with the margin between the two divs?

If I try to add for example to the first div margin-right:30px; then the width of the div will be 70% + 30px what will be overall greater than 100% and the second div will fall down.

So what is the solution for this?

Answer 1

Is this close enough?

Live Demo

HTML:

<div id="container">
    <div id="left"><div id="left2">leftgggg</div></div>
    <div id="right">right</div>
</div>

CSS:

#container {
    margin: 0 30px 0 30px;
    overflow: hidden;
    background: #f3c
}
#left {
    float: left;
    width: 70%;
    position: relative;
    left: -30px;
}
#left2 {
    height: 200px;
    margin: 0 0 0 30px;
    background: #ccc
}
#right {
    height: 200px;
    float: right;
    width: 30%;
    background: #666
}