It’ll take a lot of coding, changing of CSS classes and ID’s, everything. It’s a big task to take on. Are you really sure you want to? ??
Actually, I plan to do just that to my site ( https://www.jasoco.net/ ) over the next few weeks. It’s not going to be easy.
And after the forums (Or before maybe) I’ll be doing the same thing to my Gallery.
Boy is this going to be fun!