Widget spacing

Hi,

This is my website https://66.147.244.220/~jardinf0/?page_id=22
I want to change the spacing of the widgets in the right sidebar. Basically I’d like to add some space between the Opening Hours section (text widget) and the map.
I used web inspector to try and find the code and when I modify in web inspector it works (I added a margin-top of 40px).
However, when I copy the code into wordpress editor as follows…

h3 {
margin: 10px 0;
margin-top: 40px;
font-family: inherit;
font-weight: 700;
color: inherit;
text-shadow: 0 1px 0 #fff;
}

… it doesn’t work. Can someone point out where I’m going wrong in the syntax?

Thanks!