Vallis is a free Joomla ® 2.5-Style Administrator Template for Joomla 3.x. It is fully Responsive and has 3 color options (Blue, Red and Green). Vallis is the Joomla 3 admin template based on Bootstrap
from Twitter and the launch of the Joomla User Interface library (JUI). If you are missing Joomla 2.5 Admin Panel you can use Vallis.