One way to do that is to use text-shadow
and overlap multiple shadows:
.introText {
text-shadow: 0 0 1px black, 0 0 1px black, 0 0 1px black, 0 0 1px black;
}
4 times in this case.
Example:
.introText {
font-family: "Nunito", sans-serif;
text-shadow: 0 0 1px black, 0 0 1px black, 0 0 1px black, 0 0 1px black;
color: white;
font-size: 50px;
margin-top: 20vh;
}
<h1 class="introText text-center">We've got your perfect spot.</h1>
It creates a very similar effect and you can make it stronger or weaker depending on how many repetitions you use.