html {
    font-size: 14px;
}

@media (min-width: 768px) {
    html {
        font-size: 16px;
    }
}

html {
    position: relative;
    min-height: 100%;
}

body {
    margin-bottom: 60px;
}

#spinner {
    position: fixed;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    text-align: center;
    background-color: rgba(0, 0, 0, 0.4);
    z-index: 4;
    display: flex;
    justify-content: center;
    align-items: center; 
}