body {
    background-color:#373435;
  }

  .container {
    width: 100vw;
    height: 100vh;
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: center;
    }
    .box {
    width: 800px;
    height: 600px;
    background: #373435;
    }
    body {
    margin: 0px;
    }