#main-page{
    background-image: url(http://portal.observables.com/system/brand/serve_image/1/5/1621726166);
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
}
#intro-block{
    margin-top: 80px;
    margin-bottom: 90px;
    padding-top: 25px;
    height: 100%;
    width: 47%;
    background-color: rgba(255, 255, 255,0.8);
    margin-right: auto;
    margin-left: auto;
    border: 3px solid white;
}
#intro-block a {
    text-decoration: none;
}
#intro-block a:hover {
     color: white;
     text-decoration: none;
}
#intro-block a:visited {
     color: white;
     text-decoration: none;    
}
.ui-page-theme-a .ui-btn{
     border: 1px solid;
}
.ui-page-theme-a .ui-btn:hover{
     color: white;
     background-color: #bfbfbf;
}
.ui-page-theme-a .ui-btn:active{
     background-color: #0096cd;
}
.footer{
    border-top: none;
    background-color: rgba(245, 245, 245,0.5);
}

@media only screen 
  and (min-device-width: 320px) 
  and (max-device-width: 480px)
  and (-webkit-min-device-pixel-ratio: 2) {
    #intro-block{
        margin-top: 50px;
        margin-bottom: 60px;
        padding-top: 15px;
        height: 100%;
        width: 100%;
    }
}
@media only screen and (max-width: 1200px) {
    #intro-block{
        margin-top: 50px;
        margin-bottom: 60px;
        padding-top: 15px;
        height: 100%;
        width: 100%;
    }
}