How can I change Navbar Tab Button Color?

[hoanghadu]

Hello everyone.
I have some troubles when optimizing navigation tab buttons background.

Here is my custom navbar tab background:

I've inserted this by editing the 'navbar_tab_background' stylevar, also in this I change the background color to 'transparent'.

But when I return to my index page, it appears like this:

In the 'navbar_tab_selected_background' stylevar, I edited background property to 'transparent' and this worked, meant that the selected navbar button will be transparent and I would able to see that background. However, it seems that the unselected navbar tab buttons are not transparent. I just want to make them transparent to see the entire navbar tab background.

In short, can anyone help me make all of these navbar tab buttons transparent?

Thank you beforehand!

PS: The embeded images are quite big in width so please follow the links posted above.