Glassy screen

.container {
      position: relative;
      margin: 2em auto;
      width: 200px;
      height: 200px;
      background: #c00;
      border-radius: 50%;
    }
    .container:before {
      content: "";
      position: absolute;
      top: -2px;
      left: -2px;
      right: -2px;
      bottom: -2px;
      background: rgba(255,255,255,.5);
      border-radius: 50%;
      z-index: -1;
    }