<section>
    <div class="content" style="--clr: #00c2cb;">
      <h1>Spotlight Effect</h1>
      <h3>Hover on this card to see the magic</h3>
    </div>
 </section>

body {
  margin: 0px;
  padding: 0px;
  font-family: "Poppins";
  background-color: #22232e;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}
* {
  box-sizing: border-box;
  scroll-behavior: smooth;
}
section {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 50px;
  flex-wrap: wrap;
}
.content {
  position: relative;
  width: 600px;
  height: 400px;
  border-radius: 20px;
  background: rgba(31,32,39,1);
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  z-index: 1;
}
.content h1{
  font-size: 3rem;
  color: #00c2cb;
  z-index: 3;
}
.content h3{
  font-size: 20px;
  color: #e0ffff;
  z-index: 3;
}
.content::before{
  content: '';
  position: absolute;
  top: var(--y);
  left: var(--x);
  transform: translate(-50%,-50%);
  background: radial-gradient(var(--clr),transparent,transparent);
  width: 600px;
  height: 600px;
  opacity: 0;
  transition: 0.5s, top 0s, left 0s;
}
.content:hover::before{
  opacity: 1;
}
.content::after{
  content: '';
  position: absolute;
  inset: 2px;
  border-radius: 18px;
  background-color: rgba(31,32,39,0.7);
  z-index: 2;
}

let cards = document.querySelectorAll('.content');
    cards.forEach(card => {
      card.onmousemove = function (e) {
        let x = e.pageX - card.offsetLeft;
        let y = e.pageY - card.offsetTop;

        card.style.setProperty('--x', x + 'px');
        card.style.setProperty('--y', y + 'px');
      }
    })