State 8, Responsive Web Design and Testing, Challenge task 2 of 2

I'm pretty sure my code is correct. I'm getting a weird error though that doesn't make any sense given the tasks for this stage.

Challenge: Inside the media query, clear the left side of every 4th list item in the gallery.

(the previous challenge was to set a width on all list items in the gallery, of 28.3333%)

My code:

@media screen and (min-width: 480px) {
   #gallery li {
     width: 28.3333%;
   }
   #gallery li:nth-child(3) {
     clear: left;
   }
 }

it won't format that right ^

The weird error: "Bummer! Be sure you're only setting the width on every 4th list item."

Huh? This challenge has nothing to do with setting a width. It's for clearing the float.

The only thing I'm not sure about is if I'm selecting the right list item. So I tried using the numbers 4 and 5 in the parentheses, but still got an error.

It was a different error: "Bummer! Did you set "clear: left" on every fourth gallery list item?"

This seems to indicate it isn't the right number in there.... I'm totally confused.