What is the current best practice for CSS responsive and accessible typography?

I’m studying this topic heavily this whole week and I can’t find a good solution.
Some say use 62.5% for root font size and others say it’s a bad idea.
Some say use rems, others view-port units…
What articles or tutorials should I study?

I have found that this often does the trick:
root{
font-size:(whateverthehellyouwant)14px}
html{
font-size: 1em + 1vw;
}
Trust me this works. I normally take it further and apply this to the line height, (changing the vw to vh)
The way it works is that it takes the root px size and applies the em units to it, then magically applying a vw to the final unit relative to the veiwport.
Which should awnser your question about units.
Dont use absolutes for that is the way of the sith. Em’s and Rems’ are your typographical friend, and the viewport width and heights are great at getting the viewport to work with the design. But use % if you can for size. it takes alot of the calc() fannying about out.