Search box under logo and header widgets?

So that's what that button is for! Ha, thanks. :)

As for the CSS, not sure if I'm taking crazy pills but the original CSS you gave me doesn't seem to be centering the search box below the other header content anymore, and the new 400px CSS doesn't seem to be doing anything at all. To make sure I hadn't screwed up the element I recreated it from your original instructions, and still the same issue.

I can give you admin privs if that would be easier for you to help than inspecting from afar.

Can you try change this:

.inside-header form.wp-block-search__button-outside.wp-block-search__text-button.wp-block-search {
    width: 100%;
}

to

.inside-header .wp-block-search {
    width: 100%;
}

It's because you are using icon instead of text now, so this class wp-block-search__text-buttondoesn't exsit anymore :)

That makes sense! That worked, thanks again for all of your assistance.

You are welcome :)