Auto-hide text under heading titles

I’ve used html rather than markdown with some success before, though I’ve used <big> rather than <h3> to avoid the new line issue but still have larger titles. Something like this:

<hr>
<details>
<summary>
<big> Question </big>
<hr>
</summary>

This is an answer

<hr>
</details>

<details>
<summary>
<big> Question </big>
<hr>
</summary>

This is an answer 

<hr>
</details>

<details>
<summary>
<big> Question </big>
<hr>
</summary>

This is an answer

<hr>
</details>

Question

This is an answer


Question

This is an answer


Question

This is an answer