.clearfix:after {
  clear: both;
  content: '';
  display: inline;
}

.c    { text-align: center;          }
.db   { display: block;              }
.dn   { display: none;               }
.l    { text-align: left;            }
.r    { text-align: right;           }
.dt   { display: table;              }
.dtc  { display: table-cell;         }
.dthg { display: table-header-group; }
.dtrg { display: table-row-group;    }
.vam  { vertical-align: middle;      }
.vat  { vertical-align: top;         }