Hi Michael,
Adding some custom CSS should do the job. Please try this in X > Theme Options > CSS:
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 {
color: #efefef !important;
}
Please feel free to change the color value in the code.
If the code above does not work, there might be an issue with the CSS code that you have in the Global CSS such as some CSS syntax error that is stopping the CSS code you are adding to work as expected.
To verify that, please copy all the codes that are in the Global CSS and paste it here.
It should provide some information if there are any CSS error that is causing the issue that you have to fix so that the CSS codes will work.
Hope this helps.