style.css

body {
    background: url('./resources/wallpaper.jpg');
    background-position: center;
    background-size: cover;
    background-repeat:  no-repeat;
    overflow: hidden;
    min-height:100vh;   
    font-family: 'Open Sans', sans-serif;
    letter-spacing: 2px;
}


.top, .bottom{ 
    font-size: 60px;
    color: #000;
    text-align: center;
}

#main-content{
    height:100vh;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-content: space-between;
}

#main-content h1{
    margin:0 !important;
}

.bottom {
    margin-bottom: 40px;
}


.bottom h1 .time{
    padding:1%;
    background:red;
    color:#fff;
    animation: bgchange 5s linear 2s infinite alternate;

}



/* media query at the end */
@media screen and (max-width: 600px) {
    .top, .bottom {
      font-size:40px;
    }
  } 
  @keyframes bgchange {
    0%   {background-color: royalblue;}
    50%  {background-color: rgb(20, 138, 235);}
    100% {background-color: silver;}
  }