body {
    background: #136a8a;
    /* fallback for old browsers */
    background: -webkit-linear-gradient(to right, #136a8a, #267871);
    /* Chrome 10-25, Safari 5.1-6 */
    background: linear-gradient(to right, #136a8a, #267871);
    /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */
}

h1 {
    font-size: 34px;
    color: white;
    font-family: "Playfair Display", serif;
}

form {
    margin: 50px auto;
}

.contenido-principal {
    margin: 50px auto;
    background-color: white;
    -webkit-box-shadow: -1px 20px 52px -13px rgba(0, 0, 0, 0.75);
    -moz-box-shadow: -1px 20px 52px -13px rgba(0, 0, 0, 0.75);
    box-shadow: -1px 20px 52px -13px rgba(0, 0, 0, 0.75);
}

.mensajes {
    color: white;
}

#resultado {
    text-align: center;
}

.btn {
    width: 100%;
}

.contenido-spinner {
    display: none;
}

.spinner {
    margin: 100px auto 0;
    width: 70px;
    text-align: center;
}

.spinner>div {
    width: 18px;
    height: 18px;
    background-color: #93c54b;
    border-radius: 100%;
    display: inline-block;
    -webkit-animation: sk-bouncedelay 1.4s infinite ease-in-out both;
    animation: sk-bouncedelay 1.4s infinite ease-in-out both;
}

.spinner .bounce1 {
    -webkit-animation-delay: -0.32s;
    animation-delay: -0.32s;
}

.spinner .bounce2 {
    -webkit-animation-delay: -0.16s;
    animation-delay: -0.16s;
}

@-webkit-keyframes sk-bouncedelay {
    0%,
    80%,
    100% {
        -webkit-transform: scale(0);
    }
    40% {
        -webkit-transform: scale(1);
    }
}

@keyframes sk-bouncedelay {
    0%,
    80%,
    100% {
        -webkit-transform: scale(0);
        transform: scale(0);
    }
    40% {
        -webkit-transform: scale(1);
        transform: scale(1);
    }
}