Yea if you are making a site for learning purposes, you may want to try building everything from the ground up. But if you just want to build something that works, you don't want to re-invent the wheel all the time. There are many common problems that have already been well solved by people and all you need to do is use the resource they shared. So you can invest your time in more original and advanced features.
Y'all didn't read the CSS reference books from O'Reilly nor the Beginners' Guide to HTML, did y'all? Young'uns. I had to endure FrontPage and Angelfire webpages.
bootstrap is pretty good, but u still need to do alot of css overrides to prevent every layout from looking like the default, which requires core CSS understanding.
Funny you should mention that Swoly. I actually bought CSS: The Definitive Guide, 3rd Edition from O'Reilly yesterday and am currently reviewing/using it.
Good stuff. You won't regret it. Start from the beginning of that book, work your way towards the back. You will not regret finding out what special characters and delimiters do. Also, don't forget what to do in an "!emergency".
