Yes — the size and colour of the fonts you use can impact SEO!
There are two main reasons for this: first, readability. Readability matters. At the core of SEO is, ultimately, people. You need people to find your site, to visit your site, to browse, interact and enjoy your site, and, ideally, to share your site with others.
Here’s how to enhance your site’s readability:
Pick a sensible font size — not too big, not too small. Make sure your text can be read clearly across devices: PCs, tablets, and mobiles.
- Pick a colour that goes with the background — aim for high-contrast colours. Dark colours on light backgrounds, light colours on dark backgrounds. This is especially important when designing for users with limited or impaired vision.
- Make links look clickable — don’t confuse your users; make links blue or a similar colour so they stand out clearly. If you make links the same colour as the rest of your text, users are far less likely to be able to find them, and thus less likely to peruse the rest of your site! Frustrating your users needlessly is never a good idea.
The second reason the size and colour of your text matters is slightly different. Search engines levy penalties on websites (i.e. reducing your website’s ranking in search results) if they consider you to be engaged in deceptive practices, such as attempting to include text in a webpage but “hiding” it from users’ sight.
Don’t try to hide text
Don’t try to hide text by making the text the same colour as the background, or giving text a very small size, or by hiding the element using CSS. This is a problem search engines have long faced, and they are clever; you are likely to receive a penalty from Google and other search engines for trying to hide text in this manner, and it will not improve your SEO.
However, it’s acceptable to “hide” text that’s intended to be displayed with a button or toggle, for example a FAQ button that causes the “hidden” FAQs’ text to be shown to the user.
It’s also acceptable to hide text from mobile users’ view, or include text intended only to be seen by mobile users, using CSS @media rules; Google is aware of this and it will never impact your SEO negatively; on the contrary, designing your site to be mobile-friendly is very good for SEO, and Google and others actively encourage accessible web design.
Summary
In summary: pick high-contrast colours, with readable fonts of a sensible size that can be read clearly across devices, and never try to deceptively hide text from your users’ view.