I love the Arduino and the free IDE is pretty slick. One thing however bothers me every single time ... the hard to read tiny error messages below the code.
Thank goodness, we can modify it, but this can be rather cumbersome to find the right file to do that.
The file is called "theme.txt".
Note: the location of theme.txt may be different on your system, it's typically found somewhere in the installation directory of the Arduino IDE.
Under MacOS X, I found it here:
Under Windows, I found it here:
Under Ubuntu I found it here:
In "theme.txt" you'll find this little bit of text:
# GUI - CONSOLE
console.font = Monospaced,plain,11
console.font.macosx = Monaco,plain,10
console.color = #000000
console.output.color = #eeeeee
console.error.color = #A61717
Changing the "console.error.color" would change the text color that is currently red.
Note that changing the font here does not seem to have an effect.
Change it for example to yellow:
console.error.color = #ffff00
If you'd rather have a white background (background is "console.color"), with a darker red text, try:
console.color = #FFFFFF
console.error.color = #861300
You'll have to restart the Arduino IDE after saving that file.
If the font is too small (which tends to happen with a Retina screen), use the Arduino Preferences menu, and set "Editor font size" to for example 14.