Hi, on holidaymealgifts.com/new_look/, I only changed one thing beyond color in CSS. I changed the width of 3u to 70% instead of 23.5% on line 49 of core.css. It looks good in a laptop browser, but when I take it to a mobile emulator, the header and navigation are gone.
The reason I changed that percentage is that I wanted the top section to go the width of the page. Originally it was 3 sections across, like the lower part.