<h1>Hello World!</h1>

<body>
  <button id="btn">Click me</button>
</body>
$blue: #a3d5d3;

body {
  background-color: $blue;
}
View Compiled 
document.getElementsByTagName("h1")[0].style.fontSize = "80px";

function test() {
  alert("The function 'test' is executed - hello");
}

let btn = document.getElementById("btn");
btn.addEventListener("click", (event) => {
  test();
});
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