I am watching the Rapidweaver SEO course at the moment, which I bought because I am trying to get more clients to my business websites, and I know very little about SEO.
I have just watched the part about SEO friendly HTML. One thing that I learned was to check a website without any CSS, to view the HTML structure. I checked both my websites, www.marklukens.nl and www.indetailfotografie.nl. On both websites I used the “Hide my stack” feature a lot to to make it look nice on desktops, tablets and mobile devices. However when looking at the raw HTML, it looks messy to me because a lot of content is displayed twice or even three times. Is this something that could hurt my ranking, as it could be seen as spamming for example?