I do like a bit of Deadmau5!
in regards to responsivness you should start with bootstrap (easiest) or flexbox (easy).
Bootstrap is a framework which employs flexbox for layout but also includes gadgets like sliders and nice responsive nav bars. You risk all your sites looking bootstrappy and your HTML could end up more like HTMHELL with divs and classes everywhere but that hardly matters at this stage. You can get up and running quickly with it though. You can even get themes for it.
Flex box is a CSS method for making responsive layouts. You get full control of your layout if you use it raw along with Media Queries, rather than bootstrap, but your also on your own when you want to create that nice nav or slider. personally I love flexbox.
I don’t really know any good bootstrap tutorials because I never really dived that deep into it. There’s always bootstraps website or w3schools
For flexbox, you could start here to see if you like the look of it and I can highly recommend this book