Trying to change color for H4 on one page

Hi

I am trying to change the color for the H4 on one page only.

At the moment if I look at the source it says:

<h4>Awesome Customer Care <span> </span></h4>

I saw a post somewhere here that mentioned this code to change the attributes:

.postid-46 h4 {
   color:#FFA500;
}

I added this to the Custom CSS where I have added a few other snippets.

I got the `46′ by going to edit the page and it says: post=46&action=edit in the URl

So I thought from this the H4 text as above should now be in an orange color but it’s not.

Have a gotten it all messed up or should that work?

I only want to change the H4 on this page only, or is there another way?

Thanks
Ernie