.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.5);
  }
  
  .modald-content {
    background: url('../img3/fireworks.gif');
    background-position: center;
    margin: 5% auto;
    /*padding: 20px;*/
    /*border: 1px solid #888;*/
    width: 80%;
    background-color: transparent;
    text-align: center;
  }
  
  #fireworks {
    width: 800px;
    height: 380px;
    border-radius: 20px;
    background: url('../img3/30aniversario.jpg');
    background-repeat:no-repeat;
    margin: 20px auto;
    background-size:cover;
  }

  @media (max-width: 600px) {
    #fireworks {
      background-size: 300px 200px;
      width: 300px;
      height: 200px;
    }
.modald-content{
  margin: 35% auto;
  width:100%;
  padding: 20px;
}
  }
  
  #close-btn {
    background-color: rgb(21, 21, 100);
    color: #fff;
    height: 50px;
    width: 100px;
    padding: 10px 20px;
    border-style: 1px solid;
    border-color: #fff;
    border-radius: 20px;
  }

  #close-btn:hover {
    background-color: #fff;
    color: rgb(21, 21, 100);
    border-style: 1px solid;
    border-color: rgb(21, 21, 100);
  }