Template css has support for Tabs GK4 and you are using Tabs GK5 so some of the css classes are in conflicting with each other.
What you can do is enable forced css in module settings > advanced settings > Force Css "enabled".
If that doesn't solve it then you will need to remove tabs related css from templates css files if you are not using Tabs GK4 module.
Otherwise use Tabs GK4 until if template gets updated with Tabs GK5 style.
See you around...