I am working on a responsive site layout where the content area for certain pages may have a right hand side info panel and others might not. I am building this site within a custom CMS that my work uses. Now, we use *Templates* where all the HTML structure is created and use macros to pull in the content that the client enters via the CMS.

Usually I would create a separate template for the pages that would use the right hand panel and a separate template for those that don't but as the client might want to add the right panels to pages that don't have them in the future, I was wondering if there is some *overwrite style* that I can add to my template so that the whole site can run on one template rather than having to add a template that has the right panel for one page and a template that doesn't for another.

My code would be something like this:

**CSS:**

```
section#maincontent {width:720px; float:left;}
aside {width:240px; float:right;}

```

**HTML:**

```
<section id="maincontent">[conetent]</section>
<aside>[right_panel]</aside>

```

Is there a piece of javascript/CSS/web magic that can overwrite the right panel div if the client decides to add/remove the right panel from a page/template so that the maincontent fills the width of the page without having to create a new template with the style added/removed?