I've been designing barely acceptable web UIs for my side projects for 17 years now and I think this is poor advice.
I've found that bootstrap remains the best option to create a reasonably responsive, simple layout that is still quite usable on mobile as much as on the desktop, with no more than an hours' worth of work. And you don't even need to know css really.
I've used vanilla CSS and HTML and even after hours of amateur effort the site always looks like it came from the 90s. I don't have the time to worry about what font family I want to use, is that too much to ask?
