Vertical tabs height

I have created 2 tabs, but there are not taking the full content pane height.
I need to make the height of the tabs to be 50% of the content pane.
This is the code I used in the custom CSS, but it’s not affecting anything:
#tab_container_34264 .wpsm_nav-tabs > li {
height: 50%;
}

The page I need help with: [log in to see the link]