How can I change an item in the main menu?

Hi,

I tried to change only one item in the main menu with this code:

li#menu-item-4765 span {
color: orange;
}

4765 is the id of the menú element.

Nothing happened. So I tried:

li#menu-item-4765 span {
color: orange important!;
}

And no changes.

¿Can you help me please?

Great theme! Thanks for your help