Are you saying that index.php would call all my background elements, which would then appear on all my pages if I set them to call on index.php? I thought I was using CSS to call and place the background elements? I'm sorry, I'm very confused.
Here's how I imagine it:
index.php calls my homepage, which has includes for the footer (since the header is different on every page, it's just text so I can put it in the body) and possibly the navigation? (Though on some pages the navigation shouldn't appear.) Not sure how this involves CSS.
Then on each page I just have body content, while calling the CSS for the backgrounds, and possibly the includes(?).