#popup {
      background-color: rgba(0,0,0,0.8);
      position: fixed;
      top:0;
      left:0;
      right:0;
      bottom:0;
      margin:0;
      -webkit-animation:autopopup 2s;
      -moz-animation:autopopup 2s;
      animation:autopopup 2s;
   }
      @-webkit-keyframes autopopup {
         from {opacity: 0;margin-top:-200px;}
         to {opacity: 1;}
      }
      @-moz-keyframes autopopup {
         from {opacity: 0;margin-top:-200px;}
         to {opacity: 1;}
      }
      @keyframes autopopup {
         from {opacity: 0;margin-top:-200px;}
         to {opacity: 1;}
      }


   #popup:target {
      -webkit-transition:all 1s;
      -moz-transition:all 1s;
      transition:all 1s;
      opacity: 0;
      visibility: hidden;
   }

   .popup-contenedor {
      position: relative;
      margin:7% auto;
      padding:30px 50px;
      background-color: #fafafa;
      color:#333;
      border-radius: 3px;
      width:50%;
   }

   a.popup-cerrar {
      position: absolute;
      top:3px;
      right:3px;
      background-color: #333;
      padding:7px 10px;
      font-size: 20px;
      text-decoration: none;
      line-height: 1;
      color:#fff;
   }