.modal{
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 99;
  opacity: 0;
  visibility: hidden;
  transition: .5s all ease , .5s visibility  ease;
  padding: 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  box-sizing:border-box;
  .modal__content{
    position: relative;
    z-index: 2;
    padding: 20px;
    background-color: #fff;
    overflow: auto;
    -webkit-overflow-scrolling: touch;
    flex:0 1 1000px;
    width: 100%;
    max-width: 1000px;
    max-height: 100%;
    img{
      display: block;
      margin-left: auto;
      margin-right: auto;
    }
  }
  .modal__bg{
    position: absolute;
    z-index: 1;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.8);
  }
  .modal__open,a{
    display: block;
    width: 300px;
    margin: 30px auto;    
    color:#fff;
    font-weight: bold;
    text-align: center;
  }
}

.modal.is-open{
  transition: .5s opacity ease , .5s visibility  ease;
    opacity: 1;
    visibility: visible;   
  }