Panel's css_class example not working for me

Hello, I am going through panel’s customization documentation. I have not been able to get the css_class example to work. I am using Jupyter Lab and also tried plain notebook, but doesn’t appear to work. I just get the standard look of panel.

My code in first code cell:

import panel as pn

Then in 2nd code cell:

css = '''
.widget-box {
  background: #f307eb;
  border-radius: 10px;
  border: 2px black solid;

Then in last code cell:

    pn.widgets.Select(name='Fruit', options=['Apple', 'Orange', 'Pear']),

But I just get the standard or normal look. However, if I add background='#f307eb' to individual panel objects, then the background color does update.

I am using panel version 0.9.5 installed with Miniconda3 on Windows 10 machine via conda command: conda install -c pyviz panel and then jupyter labextension install @pyviz/jupyterlab_pyviz

I found what the problem is. I did not restart my kernel when previously I had imported hvplot.pandas via import hvplot.pandas

So apparently, hvplot.pandas overrides any changes to css. Is there a way to prevent hvplot.pandas from over-riding the css_class?

I figured out that we can just import hvplot.pandas after creating css_class like so:

import panel as pn
css = '''
.widget-box {
  background: #f307eb;
  border-radius: 5px;
  border: 1px black solid;
import hvplot.pandas

Ah yes, this is pretty subtle and we should probably warn about this. What happens is that hvplot.pandas loads the holoviews extension, which itself also initializes panel. We avoid embedding Panel multiple times so initializing it a second time has no effect, which also means that any CSS or JS added after the initial load is not added.