* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
}

.hero{
    height: 100%;
    width: 100%;
    background-color: black;
    display: flex;
    justify-content: center;
    align-items: center;
}
.box{
    height: 30%;
    width: 20%;
    background-color: white;
}