From what I remember, the textbox shown behind any dialogue is actually a picture.
(
/game/gui/textbox.png
)
When you create your project, you are given a grid of colors to pick the general style used by your project.
View attachment 750605
If you pick any of the colors on the top two rows, your
namebox.png
is primarily black/gray. If you pick colors from the bottom two rows, that same picture is primarily white/gray.
It sounds like you maybe have picked the wrong base color options. Thankfully, RenPy will allow you to change it even after you've started work on your project, by using the "Change/Update GUI" option from the RenPy Launcher...
View attachment 750607
Though obviously, if you've done some extensive reworking of the GUI... that might be a bad idea - since it will probably overwrite everything you've done with the default designs.
But if you've not really reworked the
gui.rpy
a lot, it might be a quick and dirty solution for you. (Pick the "Choose new colors, then regenerate image files" option most likely).
*** Backup your project before trying... you may not like the results ***
Alternatively, just draw your own
/game/gui/textbox.png
.
This is the one I usually use in a 1920x1080 project...