Tabs: No indication of active tabs.

Problem/Motivation:
Tabs: There is no indication if a tab is active or not. If there are multiple tabs on a page then it's very difficult for the user to check which one is the current page. There should be some indication in the active tab.

To Reproduce:
Go to any node page you can see tabs section and see there is no active tab indication.

Expected Result:
There should be some indication in the active tab so that user can see which one is the current page.

Actual Result:
No active tab indication.

Proposed resolution:
Need to add some background to the active tab.