.topnav {
  background-color: #070954;
  overflow: hidden;
}


.topnav a {
  float: left;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
}


.topnav a:hover {
  background-color: #ddd;
  color: black;
}


.topnav a.active {
  background-color: #04AA6D;
  color: white;
}

.box{
    margin: 40px auto; 
    max-width: 600px;
}

  .hidden {
    display: none;
  }

  .screen-center {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100vh;
    font-size: 1.2rem;
  }

  .screen-loader div:nth-child(1) {
    animation-delay: -0.45s;
  }
  .screen-loader div:nth-child(2) {
    animation-delay: -0.3s;
  }
  .screen-loader div:nth-child(3) {
    animation-delay: -0.15s;
  }

  @keyframes screen-loader {
    0% {
      transform: rotate(0deg);
    }
    100% {
      transform: rotate(360deg);
    }
  }