Style and script tags not working within textfield

[hengiesel]

How to add external CSS in a field

You should put the CSS in the notetype styling section (or use the add-on suggested by @kleinerpirat) and apply it via a class/id. You can see the relevant code here. A summary: We want to provide better card preloading in the future (preload next card while showing current card), and for that, the field HTML may not contain any styles/scripts.