H1..H2 etc tags and search engine no-nos

[ncjbhd]

If I set my H tags up with an external CSS, to enclose most of the content on an index page (ie: headings in H1, content in H2, but it looks like regular formatted text), will the site be penalised by Google & co. for spamming? I have a boss breathing down my neck who is adamant that we pull out all the SEO tricks we can, but I'm convinced this will just lead to the site receiving less hits due to breaking the rules, whatever they are. Is it best just to use H1 tags and not bother with H2? do search engines even care anymore?

also... will a search engine pull all the keywords out of php include files used on an index page?