html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

body{
    background-color: #212529;
}

.df-main-container{
    width: 100vw;  /* 100% of the viewport width */
    height: 100vh; /* 100% of the viewport height */

    display: flex;
    flex-direction: column;
    flex-wrap: nowrap;
    align-content: center;
    justify-content: center;
    align-items: center;
}

.df-main-container main{
    width: 100vw;
    height: 90vh;

    display: flex;
    flex-direction: column;
    flex-wrap: nowrap;
    align-content: center;
    justify-content: center;
    align-items: center;

    padding: 0px 20px 0px 20px;
}
.df-main-container main img{
    max-width: 500px;
    width: 100%;
}

.df-main-container footer{
    width: 100vw;
    height: 10vh;

    display: flex;
    flex-direction: row;
    flex-wrap: nowrap;
    justify-content: center;
    align-items: flex-end;

    color: #FFF;
}
.df-main-container footer i{
    color: #e74c3c;
    font-size: 0.9rem;
    margin-right: 2px;
    margin-left: 2px;

    -webkit-animation: heartbeat 2s infinite;
    -moz-animation: heartbeat 2s infinite;
    animation: heartbeat 2s infinite;
}
@keyframes heartbeat {
      0%, 100% {
        -webkit-transform: scale(0.9);
        -moz-transform: scale(0.9);
        transform: scale(0.9);
      }
      25% {
        -webkit-transform: scale(1.1);
        -moz-transform: scale(1.1);
        transform: scale(1.1);
      }
      50% {
        -webkit-transform: scale(0.9);
        -moz-transform: scale(0.9);
        transform: scale(0.9);
      }
      75% {
        -webkit-transform: scale(1.1);
        -moz-transform: scale(1.1);
        transform: scale(1.1);
      }
    }