collapsing of markdown block after exporting to HTML

[lapotok]

Hello,

I'd like to make a markdown block that would contain a part that collapses using a <details>+<summary> html code.

# Header

Some text.

<details><summary>something to hide...</summary>
    
## Subheader
    
Some text
    
+ list element 1
+ list element 2
 
```python
print('Some code not-to-be-executed.')
test_function()
```
<br>

```
some output example
another string of output
```
</details>

It works perfectly well in Jupyter Lab

but fails after exporting the notebook to HTML.

I tried also using separate raw blocks for the <details> + tag

but it messes up the formatting and need some CSS adjustment <summary style="padding-left: 100px;">.

It would be great for export HTML to agree with Jupyter Lab preview. Thank you in advance!

[ivanov]

Hey there @lapotok I'm going through old issues and it seems to me like this issue belongs in the nbconvert repository, so I will move it there.