/****** PLACE YOUR CUSTOM STYLES HERE ******/
nav.fixed.outOfSight{
opacity: 1;
visibility: visible;
transform: none !important;
}
@media all and (max-width: 767px){
nav{ 
    position: fixed !important; 
    top: 0 !important; 
    width: 100% !important; 
    visibility: visible !important; 
    transform: none !important; 
    z-index: 999; 
    }

footnav{ 
    position: fixed !important; 
    bottom: 0 !important; 
    width: 100% !important; 
    visibility: visible !important; 
    transform: none !important; 
    z-index: 999; 
    }    
}



*{
    margin: 0;
    padding: 0;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}


.wrap{
    width: 1100px;
    margin: 50px auto;
    display: -webkit-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: center;
    -webkit-justify-content: center;
    -ms-flex-pack: center;
    justify-content: center;
}

.tarjeta-wrap{
    margin: 10px;
    -webkit-perspective: 800;
    perspective: 800;
}

.tarjeta{
    width: 300px;
    height: 350px;
    background: #3f51b5;
    position: relative;
    -webkit-transform-style: preserve-3d;
    transform-style: preserve-3d;
    -webkit-transition: .7s ease;
    transition: .7s ease;
    -webkit-box-shadow: 0px 10px 15px -5px rgba(0,0,0,0.65);
    box-shadow: 0px 10px 15px -5px rgba(0,0,0,0.65);

}

.adelante, .atras{
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
}

.adelante{
    width: 100%;
}

.atras{
    -webkit-transform: rotateY(180deg);
    transform: rotateY(180deg);

    padding: 15px;
    display: -webkit-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: center;
    -webkit-justify-content: center;
    -ms-flex-pack: center;
    justify-content: center;
    -webkit-box-align: center;
    -webkit-align-items: center;
    -ms-flex-align: center;
    align-items: center;

    text-align: center;
    color: #fff;
    font-family: "open sans";
    background: #3f51b5;
}

.tarjeta-wrap:hover .tarjeta{
    -webkit-transform: rotateY(180deg);
    transform: rotateY(180deg);
}

.card1{
    background-image: url("../img/tarjeta_1.jpg");
    background-size: cover;
}

.card2{
    background-image: url("../img/tarjeta_2.jpg");
    background-size: cover;
}

.card3{
    background-image: url("../img/tarjeta_3.jpg");
    background-size: cover;
}

.card4{
    background-image: url("../img/tarjeta_4.jpg");
    background-size: cover;
    alt:"initial";
}