CSS Reset can be used contextually by appyling CSS Reset to specific regions of the page.
When CSS Reset is included in a page it applies rules to all HTML elements via type selectors like this: h1 {margin:0;}. The contextual version uses only descendent selectors like this: .yui3-cssreset h1 {margin:0;}. This means you can put that class value on a node in your document to choose which region(s) of your page CSS Reset will be applied to.
<div class="yui3-cssreset">
<p>Everything within this container will have CSS Reset applied.</p>
</div>
Because CSS examples are susceptible to other CSS on the page, this example is only available in a new window at the above link.