hide redundant widget search title

The word "search" above the search widget is redundant.
I can hide it by adding the following to CSS in my developer tools.

.wp-block-search__label {
  display: none;
}

But adding that to additional css doesn't do anything.

I know I have a lot of questions today, but I'm so close to being able to launch and I am actually quite thrilled that I have shifted themes completely in about 8 hours of work as opposed to a week or more before GeneraetPress!