Site layout gone adrift

Overnight my ZenCart at http://www.irishshopper.co.uk has really got messed up.

Anyone any idea what caused this and what is needed to correct it ?

Thank you.

Code does not auto change over time
Use FTP to view files by modified date and look for recently modified files

Looks like a permissions thing - when I try to view your stylesheet using Web Developer, I get a 403 Forbidden message.

Seems OK now. I replaced the stylesheet.css and tpl_main_page files with the original.

One thing I discovered is it is not too fussy which stylesheet it loads !! I changed the original stylesheet.css keeping its file name and making a backupcopy called stylesheetORIGINAL.css but this is the file it loaded and used.

Zencart loads all stylesheets whose names begin with style and have the .css extension that are in the current template's css foder.