Help with @media query

HTML-CSS
1

I am on step 20 of the Learn CSS Flexbox project, very stuck. The “hint” seems to be exactly what I have in, but it keeps being flagged as wrong.
Prompt is:

Step 20

Create a media query for screens smaller than 800px in width. In that media query, create a #gallery img rule and set the width property to 50%. This will convert your gallery to a two-column layout.

My code:
@media (max-width: 800px)

The hint:

Hint

Your new @media query should have a max-width of 800px like this: @media (max-width: 800px).

2

where’s your #gallery img rule?

3

@media (max-width: 800px) {
#gallery img {
width: 50%;
}
}

4

I can’t do much without a link to the challenge.