The TL;DR is that high contrast between background and text colors is important, and that for many users, black text on a white background is a) most legible and b) most professional-appearing.

If you pick a dark background color, you may want to consider changing the text color to make it more readable by hitting the A icon (next to the highlighter icon) and choosing white or something ...

Under Background, select Solid color. Then, choose a light background, e.g., orange, and the font will turn from white to black. Then, immediately change your desktop background back to Picture ...

In the text-area, write some text. The color will be whatever is selected in Color 1 which is usually black, and the background is white (color 2) First, decide the color for your text.

The feature lets users select a color that appears behind their text status in place of the normally-white background. Several of the color options offer an Instagram logo-style color gradient ...

Black text on a white background makes for the best readability, hence the best comprehension and retention. Why? Because the color white reflects all wavelengths of the visible spectrum.