Font issues after banner change

Hi, I have tried searching for an answer but haven't found one - sorry. I am very new to using zen cart but it seems it will do everything I need once I get it set up.

I have a problem after changing my banner image - I replaced the default one with one I made - of exactly the same size and dimensions but on doing so all the font sizes changed. In the side bars the text is now much larger than it was before which has messed up the layout. I have not touched the style sheet at all so don't understand and I don't know how to fix it.

I had viewed my site just before uploading the new banner and all was fine - it only occured after refreshing to see the new header in place.

I would very much appreciate any advice.

https://www.beads-and-bobs.com

It is a new install (v1.3.8) and I have not installed any addons yet.

Thanks in advance.

Problem is that you have been hacked .. i see Iframes and javascript that only points to hacks.

you need to go to
http://www.zen-cart.com/wiki/index.php/Recovering_From_Hacks

and follow all the procedures.

you also need to apply all patches , and rename your admin folder name ..