cannot make footer text disappear

I’ve tried to remove the footer text with the following code in Additional CSS:

.site-info {
display: none;
}

It removes the footer text on the desktop version but not on any mobile versions. I’ve tried adding !important and I’ve tried specifying it for all the media queries options but it makes no difference.

I know I can change it via doing a new footer.php file with a child theme but I’d like to avoid doing a child theme if possible, to keep things simple.

Any advice appreciated.

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