It’s actually a word for the marketing, to make the customers excited and for company’s to get more money from investors. Pure bullshits.

I can recommend you this course on Udemy, it’s actually not expensive and you will get what you want : https://www.udemy.com/bootstrap-to-wordpress/ Also this one if its not enough : https://www.udemy.com/photoshop-psd-to-wordpress-theme-development-from-scratch/

Still a very great article, as a French student I was wondering about Vanilla JavaScript vs jQuery... VanillaJS is sometime harder to learn and write but im kind of crazy about optimization and VanillaJS should be the way to go before to get lazy as many developers. And right now more than 50% of website are viewed on mobile, jQuery was clearly not made for it.