[TODO] Change default styling to use flexbox for vertical alignment

[UXVirtual]

This needs improving so all HTML elements inside the preloader stay vertically centered by default.

Adding something like this to the page will work in most modern browser which support flex CSS:

<style>
.modal-content {
            display: flex;
            justify-content: space-evenly;
            align-items: center;
            flex-direction: row;
        }
</style>