Change one menu item's font and style

I would like to change the color and style of just one top nav menu item (Shop the Store!) on my site blog.bluezelia.com.

I understand that I need to add code to the CSS file. Something like this example from another support thread:

#access li.page-item-37 a {
font-family: curlz mt; font-size: 23px; color: #aabadd;
}

However, I am not sure how to identify the item number associated with ‘Shop the Store’. I am also not positive about where to add the code. I am guessing in this block:

#branding ul.menu,
#colophon #access-footer ul.menu {
font-size: 14px;
list-style: none;
margin: 0 0 0 -0.8125em;
padding-left: 0;

Any ideas?