You are right, you are not 20 years too late because CSS and html are alive and well. However, whomever starts and HTML and CSS site to teach others is 20 years too late. lol
There is no shortage of great, established sites on the subject and it will be impossible to compete with them SERP-wise. The amount of high value backlinks these sites have is amazing because everyone and their brother links to them.
Then to top it off, it's not really worth trying to compete since there is little commercial value in such a site.
The domain name is so-so, IMHO.
$50-$90 max.