There are a lot of people with problems reading websites due to small type sized and low contrast. Here is a readable font that you probably can substitute for Helvetica or Arial or other san-serif fonts.
See the Pen Readiblity by Jim Roberts (@MrRoberts) on CodePen.
I am someone who has a tendency to immerse myself it things that interest me to the point where I spend a good amount of time learning the subject to the point where I can really use the knowledge learned. Right now I am up to my eyeballs in learning CSS (Cascading Style Sheets). I did a fairly deep dive a number of years ago to the point that I was able to build websites that were at least not unpleasant to look at. Over the last few years CSS has been updated a lot. I’ve dived back into it.
One of the things I can recommend is Codepen.io a site that lets you create and test CSS and Javascript in a sandbox environment. I use it to store things that I have learned about specific CSS code such as margin and padding. This gives me a reference anytime I forget exactly what some thing does. There are a lot of wonderful code smith’s that you can follow that are doing amazing things with CSS.
Another really useful tool is the You Tube Chanel of Kevin Powell. He has over 300 video on working on the front-end of the web. I highly recommend his videos.
At the moment I’m redoing my landing page for Noded.us The code I used was state of the art in 2008, not so much now. So an update was and is in order.