#recuadro1 {
    background-color: lightgray;
    margin: 50px;
    width: 180px;
    border-radius: 15px;
    padding: 10px 30px 10px 10px;
    box-shadow: 20px 20px 20px greenyellow, -20px -20px 20px red;
}
#recuadro2 {
    background-color: lightgray;
    margin: 50px;
    width: 180px;
    border-radius: 15px;
    padding: 10px 30px 10px 10px;
    box-shadow: inset 0px 0px 20px red, 0px 0px 10px 15px lightgoldenrodyellow;
}
#recuadro3 {
    background-color: lightgray;
    margin: 50px;
    width: 180px;
    border-radius: 15px;
    padding: 10px 30px 10px 10px;
    box-shadow: 20px 20px 20px lightcoral;
}

h1#titulo1 {
    text-shadow: 5px 5px 2px lightgrey;
}
h1#titulo2 {
    text-shadow: -5px -5px 2px lightgrey;
}
h1#titulo3 {
    text-shadow: 2px 2px 3px red, 4px 4px 3px green,  6px 6px 3px blue;
}