.sup {
   line-height: 0px;
   font-size: 2px;
   color:green
}

.cross {
    position: relative;
    display: inline-block;
}

.cross::after {
    content: '';
    width: 100%;
    position: absolute;
    right: 0;
    top: 50%;
    border-bottom: 2px solid red;
    transform: skewY(45deg);
    transform:skewY(45deg);
   -ms-transform:skewY(-45deg);
   -moz-transform:skewY(-45deg);
   -webkit-transform:skewY(-45deg);
   -o-transform:skewY(-45deg);
}

#yellow {background-color:yellow;}
#red {background-color:red;}
#green {background-color:green;}