body{
    background: url(../images/fondo_login.gif);
    background-repeat: no-repeat;
    background-size:cover;
    background-position: center center;
    height:100vh;
}

.videos a {
    position: relative;
    
}
img {
    max-width: 100%;
}
body {
    font-family: 'Roboto', sans-serif;
}
.contenedor-card {
    margin-bottom: 20px;
}
@media(min-width:768px) {
    .contenedor-card {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        column-gap: 15px;
    }    
} 

@media(min-width:1024px) {
    .contenedor-card {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        column-gap: 15px;
    }    
} 

.videos {
    max-width: 900px;
    margin: 0 auto;
}
@media( max-width: 768px ) {
    .videos {
        margin:0 20px;
    }
}

.card {
    background-color: #e1e1e1;
    border: 1px solid gray;
    margin-bottom: 10px;
}

.contenido-card {
    padding: 10px 20px;
}
.contenido-card h3 {
    text-align: center;
    margin: 0;
    font-weight: normal;
    text-transform: uppercase;
}
.contenido-card a {
    margin-top: 10px;
    display: block;
    text-align: center;
    text-transform: uppercase;
    font-weight: bold;
    text-decoration:none;
    color:white;
    background-color:teal;
    padding:7px 30px;
    border-radius:5px;

}
.card img {
    max-height: 155px;
    width: 100%;
}