.mainretro {position: relative; width: 100%; height: 100%;}
.jose {width: 50%; height: 100%; float: left; position: relative; text-align: center;}
.retro {width: 50%; height: 100vh; float: left; position: relative; text-align: center; background: #e70024;}

.jose img, .retro img {max-width: 350px; margin: 250px 0 0 0;}

body {background: #05151c; padding: 0; margin: 0;}


.a {
    
   	animation: pulse 5s linear infinite;
}

@-webkit-keyframes "pulse" {
0% {
    -webkit-transform: scale(1.02);
    transform: scale(1.02);
}
50% {
   -webkit-transform: scale(0.97);
   transform: scale(0.97);
}
100% {
    -webkit-transform: scale(1);
   transform: scale(1);
}
}

@media only screen and (max-width: 900px) {
.mainretro {background: #05151c; position: relative; width: 100%; height: 100vh;}
.jose {width: 100%; height: 50%; float: left; position: relative; text-align: center; background: #05151c;}
.retro {width: 100%; height: 50%; float: left; position: relative; text-align: center; background: #e70024;}

.jose img, .retro img {width: 70%; max-width: auto!important; margin: 10%; 0!important;}
}