Joomla 3 ships with Bootstrap v2.3 but many of the template designers develop their templates using Bootstrap v3.x and there is no backward compatibility between the two releases. However, some of the template designers include a setting called “Legacy” to solve most but not all of the CSS conflicts.
JoomBri depends on Joomla Bootstrap Framework and as a result of the above scenario, some of the pages will have CSS conflicts. Although this issue is not from our end, some of our members do not understand this. We have taken utmost care to solve those conflicts and you are requested to follow the steps given below.
So simple, isn't it?