How can i apply is-toggled styles when the button is clicked clicked [closed]

The class (.is-toggled) is added when clicked on the button , but the styles for the button when clicked is not getting applied…

.is-toggled {
  background-color: lightgray;
  border: none;
  padding: 10px;
  border-radius: 5px;
  cursor: pointer;
}

.gaming-btn {
  background-color: black;
  color: white;
  border: none;
  padding: 10px;
  border-radius: 5px;
  cursor: pointer;
}

<button class="gaming-btn" onclick="
     const btn = document.querySelector('.gaming-btn');

      if(btn.classList.contains('is-toggled')) {
        btn.classList.remove('is-toggled')
      } else {
        btn.classList.add('is-toggled');
      }
    ">Gaming</button>