How to set up error highlighting in IntelliJ IDE

Question

I have red-green vision deficiency (color blindness, protanopia or deuteranopia) and it's hard for me to notice error markers

Answer

For common case of red-green vision deficiency, use "Settings | Appearance & Behavior | Appearance | Accessibility | Adjust colors for red-green vision deficiency", then restart.

Example:

If the "Accessible" section still does not look highlighted for you, you can configure error highlighting and change the color and/or add text effects like underline or underwave for certain error types. To do that, go to "Settings | Editor | Color Scheme | General" and set up custom Errors color as shown below: