<div class="flair flair--3"></div>

h1 {
  margin: 1rem;
  text-align: center;
}
.flair {
  width: 100px;
  height: 100px;
  position: fixed;
  top: 0;
  left: 0;
  pointer-events: none;
}

gsap.set(".flair", {xPercent: -50, yPercent: -50});

let xSetter = gsap.quickSetter(".flair", "x", "px") //apply it to the #id element's x property and append a "px" unit
let ySetter = gsap.quickSetter(".flair", "y", "px") //apply it to the #id element's x property and append a "px" unit

window.addEventListener("mousemove", e => {  
  xSetter(e.x)
  ySetter(e.y)
});