Set position of div relative to position of another percentage-width div

Question

I two divs set within a parent div - a sidebar on the left & a content area to the right of that. I need to set the position of my content area (which has a fixed width) to always be 15px to the right of the sidebar (even as the browser window / sidebar stretches).

Setting the sidebar with position: absolute & a % width worked perfectly for the sidebar itself, but as the sidebar position is then absolute, the content doesn't recognise where the sidebar is & can't be positioned relative to it with CSS.

Here is an image of what I am trying to achieve:

Answer 1

Why are you using position absolute for the side bar?

I would just do it like this

    <div class="container">
        <div class="sidebar">
            <p>This is your sidebar</p>
        </div>
        <div class="content">
            <p>This is your content</p>
        </div>
    </div>


.container {width:100%; height: 1000px; background:blue;} /*didn't supply a width*/
.sidebar {width:25%; float:left; min-height:200px; background:lightblue; margin-right:15px;} /*you said sidebar has a % width*/
.content {width:250px; height:200px; background:red; float:left;} /*you said content had fixed width*/

Link to JS Fiddle to have a look

Unless I'm not understanding your question?