See this gist source code for details (pun intended :) )
<details><summary>CLICK ME</summary>
<p>
#### yes, even hidden code blocks!
```python
# BEWARE when copy-pasting! MD codeblock opening and closing backticks sequences (```) contain zero-length space for proper MD formatting
print("hello world!")
```
[a link](./#)
</p>
</details>
<details><summary>### Section header</summary>
no P-tag
#### Subsection
Multiline
text.
</details>
<details><summary>
### Section header
</summary>
no P-tag
#### Subsection
Multiline
text.
</details>
* <details><summary>Topic</summary>
- sub-topic
- sub-topic
</details>
* <details><summary>Topic with P-tag</summary>
<p>
- sub-topic (`<p>` wrapping requires empty line after opening `<p>`)
- sub-topic
</p>
</details>
-
Topic
- sub-topic
- sub-topic
-
Topic with P-tag
- sub-topic (
<p>
wrapping requires empty line after opening<p>
) - sub-topic
- sub-topic (
Well, widget control looks much as a bullet itself.
<details><summary>Topic</summary>
- sub-topic
- sub-topic
</details>
<details><summary>Topic with P-tag</summary>
<p>
- sub-topic
- sub-topic
</p>
</details>
Topic
- sub-topic
- sub-topic
Topic with P-tag
- sub-topic
- sub-topic
An attempt to put <details><summary>the control</summary>for the hidden text</details> inline and all in a single row **fails**.
An attempt to put
the control
for the hidden textAn attempt to put <details><summary>the control</summary>
for the hidden multiline text
</details> inline **fails**.
An attempt to put