Hi there,
It seems that your template set it body to 60px and your current docker size is 40px. That why it shown additional white spaces on your site. Currently, give css on above reply should work but somehow your customs css is overridden, and it still use existing css style as you can see here
http://take.ms/N0FwQ.
Maybe you can consult with your that template service provider regarding this and see how it goes. By the way, if you like to make your docker bigger, using 60px, you can apply css codes below on your custom.css files.
[gist type="css"]
#es.es-docker.is-top {
height: 60px !important;
}
[/gist]
Please give it a try and see how it goes