Hi, I have recently inherited an ecommerce website and been tasked with improving SEO. I noticed a lot of pages were using several h1 tags and, with the help of my developer, used the css to overwrite the secondary headings as h2 tags. However, since doing so many of the pages have fallen 15-40 places in the SERPS. The h1 / h2 switch was the only update. Can anyone suggest why the pages would have fallen like this, and if it is a temporary measure likely to recover in time? Thanks to anyone in advance for your help...