This is Nios2Sim in dark mode! It's not perfect but it's here. Feel free to contribute and submit your pull requests.
There are two ways:
Easy but, as for now, this will restrict you to the theme arbitrarily chosen by myself. Click here to download.
You might have to make sure your Java installation is up to date, and that the correct version of Java is being used when trying to run the JAR - honestly: uninstall all versions of Java which aren't the most recent you have. You may also have to right click and "open with" a JDK platform binary.
Clone this repo, and edit these 4 lines in Nios2SimFrame
in the package gui
as you see fit:
public static final Color DARK_COLOR = Color.decode("#06011e"); //background color
public static final Color DARK_MODE_FONT_COLOR = Color.WHITE; //general font color
public static final Color DARK_MODE_INSTRUCTIONS_COLOR = Color.decode("#e75350"); //addi, sti, etc
public static final Color DARK_MODE_REGISTERS_COLOR = Color.decode("#1cd6f2"); //t1, zero, etc
Then rebuild the JAR, here's a tutorial on how to do that on Intellij: https://cs108.epfl.ch/archive/21/g/intellij-export.html
Enjoy!