#map {
    box-sizing: padding-box;
    height: 0;
    padding-bottom: calc(9 / 16 * 100%); /* 16:9 aspect ratio */
    width: 100%;
}
@media screen and (max-width: 480px) {
    #map {
        display: none; /* hide on mobile devices (esp. portrait) */
    }
}


/* … */
.loading-indicator {
    display: inline-block;
    width: 45px;
    height: 45px;
  }
  .loading-indicator:after {
    content: "";
    display: block;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 5px solid rgba(0,0,0,.25);
    border-color: rgba(0,0,0,.25) transparent rgba(0,0,0,.25) 
     transparent;
    animation: dual-ring 1.2s linear infinite;
  }
  @keyframes dual-ring {
    0% {
      transform: rotate(0deg);
    }
    100% {
      transform: rotate(360deg);
    }
  }