The DnnMDesign theme for Dnn uses Bootstrap version 3.3.6. All features of Bootstrap Css, components and javascripts can be used within the skin.
Google has designed Material Design to make a web more beautiful and more user-friendly. To combine material design and Bootstrap we have used the 'Material Design for Bootstrap' framework (MDB). MDB is powerful Material Design UI KIT that has 300+ material UI elements, 1000+ material icons, 74 CSS animations, as well as multiple built-in color schemes.
MDB is built on top of Bootstrap so that you can leverage all of the Bootstrap goodness but have the look and feel of Material Design.
To find out more about Bootstrap I would suggest you to read up on the framework and become familiar with it to get the best out of the MDesign theme. Click here to go to the official Bootstrap site.
To get to grips with all the MDB goodness, check out their site as well to see what can be achieved. Click here to go to the MDB site.