a {
    text-decoration: none;
}

.mdnlink span::before {
    content: "MDN";
    font-size: x-small;
    background-color: wheat;
    /* border: 1px solid black; */
    padding: 1px;
}

.para {
    color: cornflowerblue
}

.para+.mdnlink {
    color: darkblue;
}

.test {
    color: green
}

.test+.mdnlink {
    color: darkgreen;
}

.challenge {
    color: orangered
}

.challenge+.mdnlink {
    color: darkred;
}