Such html converted to pdf or rtf cannot reproduce correct fonts (always cg times ...). You can try this with your pdf-demo!
<div>ABC</div>
<div><span style="color: red;">ewqrtgfrt</span></div>
<div><span style="font-family: Comic Sans MS;">z45z46uz56u</span></div>
<div><span style="font-family: Comic Sans MS;"><span style="font-size: x-large;">u6u6uu66u6uzztzzzzzzzzzzzzzzzzzzzzzzz</span></span></div>
<div style="background-color: yellow;"><span style="font-family: Comic Sans MS;">fdfdkkpcxae</span></div>
<div style="background-color: yellow;">efefdfd</div>
<div style="background-color: yellow;">dfdff</div>
What we can do?
We use the newest ce version ...
regards chris