Date Selector - text colour

You have inline CSS with top and bottom padding that is hiding the text. This is the CSS:

select, textarea, input[type="text"], input[type="password"], input[type="datetime"], input[type="datetime-local"], input[type="date"], input[type="month"], input[type="time"], input[type="week"], input[type="number"], input[type="email"], input[type="url"], input[type="search"], input[type="tel"], input[type="color"], .uneditable-input {
background: #fff;
padding: 20px 10px;
border: none;
}

You have to override this. Not sure where you should add it, but this will fix it:

.ui-datepicker-month, .ui-datepicker-year {
padding: 0;
text-align: center;
}

BTW, you have a few jQuery errors on your site that may prevent the site from working properly.

Thanks Victor - much appreciated.

Where would I start to try and resolve the jQuery errors?

Start with your browser's inspection tool so you can see the errors. From what I can see, it appears that you aren't even loading jQuery on your site which is weird because WordPress auto loads it. I would turn off the caching and minification plugins to see if the problem goes away. If it doesn, then you've got the plugins configured incorrectly.

If you don't know how to use the inspect tool, this will help: https://victorfont.com/how-to-use-your-browsers-inspect-tool/

It would be nice to see a little more control in the style panel for the date picker.

@squarepixel: What you are asking isn't possible within Formidable. The datepicker is a jQuery widget that uses jQuery UI for its design. jQuery UI offers a theme builder that you can use to customize your own jQuery widgets: http://jqueryui.com/themeroller/#!