Vaadin tabsheet bar height + style

How do you change the vaadin tab sheet top level bar that holds the names of each tab. I want to play around with the size (height) of the bar and change its color and other available attributes?

I have tried this but it does not work:

.v-tabsheet-tabs-minimal .v-tabsheet-spacertd div,
	.blue .v-tabsheet-tabs-minimal .v-tabsheet-tabitem,
	.blue .v-tabsheet-tabs-minimal .v-tabsheet-tabitem-selected  {
	        border-color: #7c8a91;

Anyone know how to change the size of the tabsheet top level bar. See screenshot

Have your tried changing the style of :
table.v-tabsheet-tabs {

I do some styling on the tabs using :
.v-tabsheet-tabitem .v-caption{

Also note that you can not change directly the background color as it is a picture, you will need to remove the picture first :

You should consider using webinpsector/firebug to fiddle more easily with css

+1 For the firebug suggestion, i am now able to separate each tab item in the tabsheet but for some reason cannot manipulate the exact width between each one

Here is what i did to separate the tabs:

.v-tabsheet-tabs {
    border-collapse: separate;
    empty-cells: hide;

Now how to add the width between each one?