For this lesson I believe it is probably asking for you to target specifically all fieldset elements. So, if you will, please ask for help in the manner that @anon42932716 suggested so that we may know specifically what step it is and what it is asking you to do.
Hello and welcome to the forums. I can completely understand your frustration. However, this is asking you to target all of the fieldset elements. If you look at your CSS code you will see you have both a fieldset and a fieldset:not(:last-of-type) selector. It is asking you to place the required code in the regular fieldset selector.
That’s okay. Frustration gets the best of us sometimes. When it’s frustrating you to the point that you cannot think clearly sometimes it is best to step away for a bit and take a break then either resume trying on your own or seeking help as you did here.
Regardless, I am truly thankful that you managed to pass and move on. Keep up the great work!