To explain what style encapsulation means, we will look at how Angular does it. On this screenshot an h1 style is converted to _ngcontent-lvy-c0 class during compilation, and so it does not leak out styles to other components and the app. You can declare another h1 style in another component and that will not have any effect on this component, guaranteed by Angular. Or its children, which might be even more important (so it's more than just nesting css in an HTML selector tree).
There is very little information about Blazor on the internet. Even less as far as enterprise / professional Blazor development is concerned. Blazor is not exactly new, but still, it feels more as an undercover platform, even today in May of 2020. This Q/A session with Tim Corey is meant to fill the gap. Tim is a software developer, consultant, trainer, and Microsoft MVP. He runs a YouTube channel dedicated to making the process of learning software development easier.