@mixin space ($height){
    height: $height;  
    float: left;
    width: 100%;
   
}
.space-15{
    @include space(15px);   
}
.space-30{
    @include space(30px); 
}
.space-45{
    @include space(45px); 
}
.space-60{
    @include space(60px); 
}
.space-75{
    @include space(75px); 
}
.space-90{
    @include space(90px); 
}