The style for card can be set on Backlog or Task boards, by clicking settings.
In the popup window select the styles tab. Then you can setup style rules similar to below.
In the above rule is set to color the card in reddish if the Bug is Critical.
Board shows Rule in action.
If bug is set to different Severity.
Multiple rules can be added and rules can be enabled disabled.
This will add lot of value to daily scrums, and in other team meetings, since board now effectively showing
- Items require immediate attention like Critical bugs.
- Task or Stories not attended for some time.
- A User Story/PBI that is changed after work started on iteration.
For TFS on premise, these will be available in future updates to TFS2015.