I'd be very interested to see what kind of problems a bit more specifically, mostly because i personally haven't read or heard about people actually having such problems, even with larger apps (one example would be gitlab).

I'd say i trust them even more after i've seen how they handled the situation. Promptly and out in the open. Trust is a very personal thing though, and if you find yourself having doubts, the alternative is bitbucket.

Have you tried explicitly setting preserveAspectRatio to none? I found in the past that it behaves rather inconsistently when it isn't set in some browsers.

I am also going to say CSS first. Doesn't even matter what you're learning, you need to understand the fundamentals. I get really frustrated when so many tutorials for complete beginners throw a framework behemoth like bootstrap into the mix. I understand why they do it, but i would suggest that you actually stay away from frameworks untill you can basically achieve what you want with just pure css. This doesn't only apply to CSS, nor even just programming/design. Then if you feel you need to speed things up you can either reach for a framework, or better yet, while getting a firm grasp on the fundamentals, you end up with kind of a 'framework' of your own.

I went with the same approach. I never really got very comfortable with preprocessors and this way lets me write just CSS with all the bleeding edge stuff (which was often inspired by what preprocessors have to offer)

Even though we are developers, we make products for people, with people. So contact in larger companies might be delegated via project managers, but in case of the smaller ones (like the one i work at) i have direct contact with clients. I don't much like it, but i got used to it with time. It highly depends on the client, some turned out to be great wworking with them, some are quite nightmarish and the whole range between those two extremes.

They should fix those links yeah. They just released their 1.0 version and made a bunch of changes (including moving the rest of the docs off github pages - which is why the links are broken). If you're interested in actually finding out more about it, their official documentation would be the place to go. In short though, it's a standards compliant UI framework.