twitter bootstrap - is it possible to undo "container" margins - css

Question

my html looks like this:
<div class="container">
<div class="header-content">
hello!
</div>
</div>
i've recently come into a situation where I need the 'header' to be 100% the window for a full-width background. usually i would do this css:
<div class="header-background-color">
<div class="container">
<div class="header-content">
hi!
</div>
</div>
</div>
unfortunately, i am fairly deep into a framework and can't wrap the container. i need to construct it within the container.
<div class="container">
<div class="header-background-color">
<div class="container">
<div class="header-content">
hi!
</div>
</div>
</div>
</div>
i can't figure out a way to accomplish this, and am wondering if this is possible.
if i use this css for header-background-color
background: blue;
left:0;
position: absolute;
width: 100%;
the element looks right, but the page flow is interrupted.
does anyone know if my target goal is reachable?
i made a bootply to illustrate this http://www.bootply.com/129060

Answer 1

You can use a child (>) selector to select the first container element and set its width to 100% and remove the padding.
.example-3 > .container {
width: 100%;
padding: 0;
}
This assumes you'll always have a wrapper around it with a unique class name (or use body if it's the first div), but this also allows you to remove the position: absolute which is causing the overlap and the height can stay dynamic.
See forked bootply: http://www.bootply.com/129065
I've added a button that inserts a paragraph into the div so you can see how it's not affected by changes in height.

Answer 2

Only thing I can think of is using a dumby element to maintain the vertical space (i.e. set the height), and then use absolute positioning on the full width content (as you mention). This is really ugly and won't be a good solution if the height of the content is dynamic.
See #content_dumby element in forked bootply: http://www.bootply.com/129063