#btnlg {
    background-color: #840000;
}

#caja {
    background-color: #4c4c4c;
    width: 100%;
    height: auto;
}

img {
    display: block;
    margin-left: auto;
    margin-right: auto;
    margin-top: 40px;
    width: auto;
    height: 40vh;
    -webkit-animation: spin 5s linear;
    animation: spin 5s linear;
}

@-moz-keyframes spin {
    from {-moz-transform: rotateY(0deg);}
    to {-moz-transform: rotateY(360deg);}
}

@-webkit-keyframes spin {
    from {-webkit-transform: rotateY(0deg);}
    to {-webkit-transform: rotateY(360deg);}
}

@keyframes spin {
    from {-webkit-transform: rotateY(0deg);}
    to {-webkit-transform: rotateY(360deg);}
}

.login {
    position: absolute;
    top: 50%;
    left: 50%;
    margin: 0px 0 0 -150px;
    width: 300px;
    height: 300px;
}

    .login h1 {
        color: #fff;
        text-shadow: 0 0 10px rgba(0,0,0,0.3);
        letter-spacing: 1px;
        text-align: center;
    }

input {
    width: 100%;
    margin-bottom: 10px;
    border: none;
    outline: none;
    padding: 10px;
    font-size: 13px;
    color: #000;
    text-shadow: 1px 1px 1px rgba(0,0,0,0.3);
    border: 1px solid rgba(0,0,0,0.3);
    border-radius: 4px;
    box-shadow: inset 0 -5px 45px rgba(100,100,100,0.2), 0 1px 1px rgba(255,255,255,0.2);
    -webkit-transition: box-shadow .5s ease;
    -moz-transition: box-shadow .5s ease;
    -o-transition: box-shadow .5s ease;
    -ms-transition: box-shadow .5s ease;
    transition: box-shadow .5s ease;
}

    input:focus {
        box-shadow: inset 0 -5px 45px rgba(100,100,100,0.4), 0 1px 1px rgba(0,0,0,0.2);
    }