Is it considered grey/black hat SEO if I modify the sizing of the headings? : <p>The situation is the following:</p>

<p>The page's title is H3, the article's title is H2 and some keyword/important sentence is H1 in the article. They have custom css classes on them, so the H3 looks like a H1, and the H1 looks like normal text. Is this considered grey/black hat SEO, or Google doesn't care about their rendered size?</p>
