In its current state… maybe? How willing are you to do custom work and/or maintain it for your purposes?
If you want a pip- or conda-installable custom style tool compatible with JupyterLab 3, there is also (disclaimer: maintainer) GitHub - deathbeds/jupyterlab-fonts: Data-driven Style and Typography for JupyterLab powered by JSS. (previous thread). It offers settings and notebook-based style customizations. It’s powered by jss which allows for tricky things like font faces (hence the name), media queries and nested selectors.