I've installed IWD Onepage Checkout, and I'm trying to style it.
Rather than edit the 'core' installation, I want to add my own stylesheet -
I've added this to /app/design/frontend/default/<theme>/layout/local.xml
<opc_index_index>
<action method="addCss">
<stylesheet>css/custom-opc.css</stylesheet>
</action>
</opc_index_index>
..however, my stylesheet isn't getting added?