Answer 1

CSS can not select a parent div only when a specific child or descendent element is hovered. You'll need some JavaScript to achieve what you seem to want.

JavaScript can be added to add something like a "hovered" class to your parent element when various mouse or touch events happen on the child div. You could edit the CSS properties directly in JavaScript but I would use a CSS class just to keep more of the CSS concerns separate.

The :hover is closely related to your question but it doesn't solve your requirements. :hover lets you select elements that are hovered over. If the child is hovered, the parent is also hovered. There is a problem though.
Here is an example of the problem with :hover:
HTML:
<div class="my-parent">
<button id="ok">OK</button>
<button id="cancel">Cancel</button>
</div>

CSS:
.my-parent:hover {
background-color: green;
}
Say you want the background of my-parent to go red when hovering over "OK". The above example will do that. The problem is it'll go green when hovering over the Cancel button too.