CSS new symbol discovered

In the Accessibility quiz, step 13:
nav > ul{
justify-content: space-evenly;
display: flex;
what does the “>” do? Which other symbols are used, “<” ? Where can I find more info regarding CSS? Is there a better suggestion than W3Schools?

this means that you want to target the direct child element of nav (the direct ul child element of nav)

Just google up ‘css selectors’ and you will find many explanations.