Use of "text-decoration-color" is not working

text-decoration-color has minimal browser support

Instead, you can use something like a span to re-colour your text:

p {
  color: red;  /* colour of underline */
  text-decoration: underline;
}

span {
  color: black; /* original colour of p */
}

<p><span>underline is red, text is black</span></p>

Your code is likely to affect another class

p {
    text-decoration: underline;
    text-decoration-color: red!important;
}

<p>test</p>

Related