Showing/Hiding sidebar based on page – almost there but need help!

Hey all. I’m setting up a site as more of a CMS with a blog page on the back end. The page links are running in a menu across the top, and for most pages I’ve managed to hide the sidebar(s) based on the page. I’m doing this with this bit of code in the header:

<?php if (is_page('blog') || is_single()){ ?>
<style type="text/css">
#content
{
  font-size:15px;
  float:left;
  width:590px;
  padding:0 0 0 1em;
}
</style>
<?php } else { ?>
<style type="text/css">
#sidebar
{
	display:none;
}
</style>
<?php } ?>

What that’s doing is hiding the side bar if the page is not a blog or single post page, and showing it if it is. Currently this is working on the “static” pages and the single post pages – but not on the main blog page.

Here’s where I’m running into trouble: I set the blog page up as “Blog”, and the slug is “blog”. However, when I do go to the blog page, the slug is the name of my current post: “sample-post”.

Is there a way to check for the main blog page? Thanks for your help!