CSS Flexbox Guide (https://www.internetingishard.com/)
Learn Responsive Design (https://web.dev/learn/design/) (https://www.internetingishard.com/html-and-css/responsive-design/) [from Interneting is Hard]
Interactive Guide To Flexbox (Very Intresting) (https://www.joshwcomeau.com/css/interactive-guide-to-flexbox/)
Typical use cases of Flexbox (https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Flexible_Box_Layout/Typical_Use_Cases_of_Flexbox)
https://careers.bcg.com/search-results?rk=page-targeted-jobs-page324-prod-n6mBQm
How to think like programmer (https://www.pdfdrive.com/think-like-a-programmer-an-introduction-to-creative-problem-solving-e156859116.html) (https://www.freecodecamp.org/news/how-to-think-like-a-programmer-lessons-in-problem-solving-d1d8bf1de7d2/)