<div class="wrapper">
  <div class="box">Hover Me!</div>
</div>

.wrapper {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}
.box {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100px;
  height: 100px;
  background-color: red;
  &:hover {
    background-color: blue;
  }
}