*{
    margin: 0;
    padding: 0;
    font-family: sans-serif;
    box-sizing: border-box;
    
}

body {
    /*background: #dedede;*/
    display: flex;
    min-height: 100vh;
    background-image:  url(../img/portada.jpg); /* foto de portada y centrar  */ 
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

form {
    margin: auto;
    width: 50%;
    max-width: 350px;
    background: #F2ECEC; /* color de formulario */ 
    padding: 60px;
    border: 3px solid rgba(0,0,0,0.2);
}

h2{
    /*text-align: center;
    margin-bottom: 8px;
    color: rgba(0,0,0,0.5);*/
    text-align: center;
    font-size: 26px;
    font-weight: 300;
    line-height: 1.4;
    color: #337ab7;
}
input {
    display: block;
    padding: 9px;
    width: 100%;
    margin: 10px 0;
    font-size: 15px; /* fuente de los cajones*/

   
}
input[type="submit"]{
    /*background: linear-gradient(rgb(56, 187, 199),rgb(60, 10, 31)); /*rgb(162, 10, 10),rgb(60, 31, 31)*/
    background: linear-gradient(#337ab7,#2E75B2);
    border: 1;
    color: #ffffff;
    opacity: 2;
    cursor: pointer;
    border-radius: 20px;
    margin-bottom: 1;
    font-size: 20px;
}
input[type="submit"]:hover { /* esssss cuando pasa el mause en el boton*/
    opacity: 0.8;
}
input[type="submit"]:active { /* es cuando de hace click en el boton*/
    transform: scale(0.95);
}
@media (max-width:768px){
    form {
        width: 75%;
    }
}

@media (max-width:480px){
    form {
        width: 95%;
    }
}