Vaadin’s Style is nice… if you’re styling one lonely component with a full server-side identity and a therapist. But what about all those poor elements you don’t even have a reference to?
Introducing Viritin’s upgraded Style, now with:
Style any Element, even the forgotten middle children.
them using CSS selectors, even inside shadow DOM. You can also apply the same style rules to any number of elements, instead of defining the n times for each and every (fine, you can also write a method for this 
).
Inject proper CSS into host page (no messy inline spam)
Strongly typed colorandbackgroundColor(thanks to this thing)
You could possibly express the whole Lumo theme in Java now 
Which is either brilliant or worrying. Possibly both.
Simple demo:
addons.dokku1.parttio.org/styling
More magical chaos:
GitHub examples
Use it. Abuse it. And stop injecting style tags from JS like it’s 2015.