Hey! You can change the colors by copying the Direct.txt theme file to a new file like HzHz.txt and adding the following lines:
spectrum_analyzer_main: 255,90,120 spectrum_analyzer_secondary: 70, 160, 255
You an access the file by following the directions here: https://minimeters.app/help/theming/ Make sure to rename the file as Direct.txt gets overwritten at launch.