I cant speak to these videos, but most flexbox tutorials are quite long. The number of videos may be a sign of completeness.<p>The core of flexbox, and the most powerful and commonly used parts, isn&#x27;t that much material, and isn&#x27;t very hard to learn. But there&#x27;s a long tail of corner cases and tricks and special situations.<p>There&#x27;s one other reason too: flexbox is at it&#x27;s most powerful and most simple, IMO, when you put flexboxes inside other flexboxes. But that inherently mixes markup and styling. Some of flexbox&#x27; features are designed to help you avoid mixing markup and styling, but that adds to the complexity.<p>CSS is somewhere between inherently complicated and a broken mess. That&#x27;s not the most charitable way to put it, but not entirely inaccurate either.