what does within 3% of the true proportion mean?

I was studying statistics and encountered this survey.

• We are running a survey to determine the 3rd graders’ favorite ice cream flavor. There are 340 third graders at our local elementary school, and we suspect that 25% of them like chocolate. We want to make sure that we get within 3% of the true proportion of chocolate-lovers in our results, 95% of the time.

What does " within 3% of the true proportion" mean?
I did some research, and I guess it’s the margin of error. However, then I thought if that phrase was related to the margin of error, it would say "within 97% of the true proportion" since the margin of error represents the range of the true value. So I couldn’t really understand what it meant. Can someone please explain?