For now, just learn the basics (simple html, simple DOM manipulation, simple jQuery, simple CSS, simple Javascript).
Those fancy frameworks are all going to be obsolete in 2 years anyway (i.e. angular 1.0). Besides, you need to know the basics in order to use the fancy frameworks CORRECTLY.
Unfortunately, most employers want you to be an expert already in whatever tools they are using. I know people will object and say they hire for talent and not resume keywords, but that hasn't been my experience as a candidate.
The reason employers want full-stack instead of back-end is that it cuts down on the communication overhead. You can do it all yourself, rather than handing off the front-end bit to other people. I'd rather hand off tricky front-end work to someone who knows it better.
My experience is mostly back-end, but recently I've been doing some simple front-end work. It makes more sense to have separate back-end and front-end specialists, but that isn't the way things are done anymore.
I wrote a video poker practice game in Javascript/jQuery/PHP/C++. It works, and my father is playing it, and he likes it. It isn't fancy modern web style, but it runs and gets the job done. (Javascript/jQuery on the client, with simple CSS. PHP with a shell_exec to C++ to do the calculation of the optimal strategy. The client does an AJAX call to get the next hand.)
Try writing something like minesweeper or a sudoku game in Javascript/CSS for practice.