body {
    background: url(../img/close-up-colorful-pins-maps.jpg); 
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    min-height: 100vh;    
}

main .container {
    background-color: #fff;
    box-shadow: rgba(0, 0, 0 .24) 0px 3px 8px;
    padding: 40px;
    border-radius: 10px;
    max-width: 800px;
    width: 100%;
    /* width: 800px; impede responsividade no mobile */
    opacity: 85%;
}

main h5 span {
    font-weight: bold;
}

.alert {
    display: none;
}

.alert.active {
    display: block;
}

button {
    margin-top: 15px;
}