Why this👉~👈css is not working inside form element? And which term is used to call it?

Question

<form>
<input>
</form>
<div>visible</div>
<style>
input:focus ~ div{
visibility:collapse;
}
</style>

Answer 1

The next sibling must have same parent

https://code.sololearn.com/W8Cp1tXTJJ0p/?ref=app