After having a quick look at the existing site which seems to use Gif text almost exclusively you have moved on to using FW with the CSS button on and Html text.
Before with gif text everything was a graphic so nothing interacted with anything else.
Now with layered items and html text the game has changed.
Different Browsers and OS will render html text at different sizes depending on a user’s preferences.
Layered items (created with CSS button on) are independent of other layered items on the page. If the text in 1 box is displayed larger than you expected then its container will expand and overlap other containers. Allow for ‘wriggle’ room. Set your text in px sizes - or better style use FW’s RPL action.
But if you want to go down the best route then design your site using an inline method so that items that expand will push others down the page and not overlap.
These are general tips until we can get a look at the underlying code of your site.