The site is called W3Schools and it is about leaning to code with HTML. The sites homepage does validate. The second page also validates. I found 3 errors on the fitst page and 20 on the second. I would say the design is a 8/10. I think it gets the job done and looks good but its not the best I have ever seen. I would say the usability is a 10/10. I had no issues navigating the site and everything worked as intended. I would say the site meets its purpose very well.