There is no selector :first-of-page, so no, you cannot use CSS exactly. In no way in CSS do not extract all h1 from the page, regardless of their parents and previous siblings, and take only the first. You need to know a little more about your h1 elements.
Examples:
- h1, ( )
body > header ( #header HTML 4.01) - h1 ,
h1:first-of-type - h1 ,
body > nav + section > h1 . , , body > header > nav + section > h1:first-of-type