Why was my question put on hold?

Your question has been put on hold (not closed), because it seems to be just about HTML and CSS, something that can happen without WordPress even involved.

Second, there is a whole support forum for this theme. That's the place to ask such a question.

And third, you haven't done anything to resolve the problem. Not even the most basic check with the code inspector. This is not how Stack Exchange works, we are not a do my work for me community.

Problems occurring within a WordPress context do not make them WordPress specific problems.

Third party plugins and themes are off-topic. That reason is noted in the close message:

Third party plugins and themes are off topic, they are better asked about at their developers' support routes.

Your question is about:

1. A third party theme, Storefront
2. And a third party plugins, WooCommerce

Which is clearly stated in the question:

I've just done a default woocommerce installation with the storefront theme.

And reiterated in a comment:

This is about wordpress; it mentions a specific Wordpress theme for a specific Wordpress plugin.

No mistake was made. The question is off topic. You may search this "meta" site for lengthy discussions of that rule if you are curious. Not everyone agrees with the rule, by the way, but it is current policy nonetheless.

Additionally, the problem is likely a CSS issue, which would be off-topic in its own right:

Generic PHP/JS/SQL/HTML/CSS questions might be better asked at Stack Overflow or another appropriate Stack Exchange network site.

On top of that, your question essentially boils down to "Here is a picture of the problem. Somebody fix it." That is a poor quality question, in that there is too little information to actually answer it. Sure, it looks weird, but none of the relevant code is provided. That is much like calling your mechanic and saying that "my car makes a clacking sound. How do I fix it?"

If you wish to have the question reopened (taken off hold), find some reason to suspect that WordPress Core is the problem or consider creating a child theme. The child theme would not be third party code. It would be your code and thus first party code. You would nonetheless need to provide more than a picture of the page to get an answer that is more than just guessing, and you would need to demonstrate your attempts to solve the problem yourself or you will like get a number of downvotes, and still no answer. And "Generic PHP/JS/SQL/HTML/CSS questions" will still be off topic whether it is your code or not.