If you haven't tried, after you use Cmd-Ctrl-F to make Chrome fullscreen you can use Cmd-Shift-F to toggle the UI elements (tabs, search bar & bookmark bar). Although it doesn't follow your mouse hover which is somehow annoying.
I appreciate the work, but I'm feeling some pure visual effects might be unnecessary. When you can scroll effortlessly on a screen and have effectively infinite space, do you still need to squeeze a lot of elements to a small area? Instead of using image sliders, view switchers or tabs, you can consider using a larger container and show all contents at the same time, with the help of js-free flexboxes or grids.
CSS imports are not equivalent of JS imports and it doesn't make sense to blame JS. The source is just a series of declarations and no dependencies, and it's simple and clear how they override each other. CSS doesn't have namespaces or modules until web components, so when you import another source you cannot choose what symbols to include (or they just don't have symbols at first place). It's almost a syntax sugar of including another <link> tag in HTML. CSS imports and JS imports have the same name but they don't have anything more in common.