Active cell is too bright in dark themes

[iiey]

Installed new environment in conda:

conda create -n jupyter -c conda-forge notebook
pip install jupyterthemes
pip install --upgrade jupyterthemes

• environment

  
  s$ jupyter --version
  jupyter core     : 4.7.1
  jupyter-notebook : 6.2.0
  qtconsole        : not installed
  ipython          : 7.21.0
  ipykernel        : 5.5.0
  jupyter client   : 6.1.12
  jupyter lab      : 3.0.10
  nbconvert        : 6.0.7
  ipywidgets       : not installed
  nbformat         : 5.1.2
  traitlets        : 5.0.5

$ firefox --version Mozilla Firefox 78.9.0esr

* **command**
```sh
jt -t onedork -T

Problem is the same for any themes.

How can we fix it? Thank you in advance!

[Kipparis]

Use -vim option. For example jt -t onedork -vim -T

[iiey]

Thank you very much. It works out for me. It makes sense to have extra warning about -vim in README