Description:
When making a fillable pdf form, and using a formatted text box to allow text input on the form, the text color is broken. 

Using "Control Properties" > "Font ..." > "Font Color", then choosing "black" is chosen as the input text color. Export as pdf, then open the pdf and fill text in the fillable text box. This input text actually shows up light gray instead of black.

I personally verified with Adobe Acrobat Reader on Windows, but it has been documented here as well: https://ask.libreoffice.org/t/i-am-unable-to-make-the-input-text-for-a-formatted-box-black-in-color/24789

When dark gray (or another color) is selected as the input text color instead of black, the text color displays as intended. Note: On my system, the darkest gray is called "Dark Gray 4", but the forum post linked above from 6 years ago calls it "Gray 10". I assume these are the same thing, just renamed over time.

Steps to Reproduce:
1. Open document in LibreOffice Writer
2. Open Form Controls toolbar and create a form text box.
3. [this is likely to be default, but confirm just in case] Open Control Properties for the text box. Scroll down to "Font [...]" and click the three dots. Confirm that "Font Color" is set to "Black".
4. File > Export as pdf [...]. Ensure "create PDF form" is checked. Export.
5. Open pdf file with pdf viewer.
6. Type into text box form and observe the color of the input text.

Actual Results:
Input text appears as light gray in color.

Expected Results:
Input text should appear as black in color.


Reproducible: Always


User Profile Reset: No

Additional Info:
I haven't verified if this is related to Dark Mode on computer displays or not.

I am currently making the pdf using LibreOffice on Ubuntu, and viewing the pdf in Adobe Acrobat on Windows, but I suspect this issue persists across OSs and softwares, given the forum post from 2017.