We can use id to override styling too. id should have a higher priority than class, so its rules apply if a conflict occurs.

<style>
  body {
    background-color: black;
    font-family: Monospace;
    color: green;
  }
  .pink-text {
    color: pink;
  }
  .blue-text {
    color: blue;
  }
  #orange-text{color:orange;}
</style>
<h1 class="pink-text blue-text" id="orange-text">Hello World!</h1>