Bootstrap 3 portrait style col-md

I'm trying to create a custom property col-md

in Bootstrap 3. What I need is the same properties as the other predefined styles, for example:

.col-md-2 {
  width: 16.6667%;
}
.col-md-2 {
  float: left;
}
.col-md-2 {
  min-height: 1px;
  padding-left: 15px;
  padding-right: 15px;
  position: relative;
}

      

        
        
        
      

    

And I want to create a new one with width: 20%

, but the thing is that when I use one of the predefined bootstrap styles for example col-md-2

and view the page in portrait it doesn't use the width and float properties (really don't know why, I researched the element with firebug and it's just like the float and width properties weren't declared when I view the page in portrait mode), but when I declare a new one and look at it in portrait, the stationary objects use the width and float properties and the element doesn't look responsive ...