@zperk13 Hello Zahary! You should be able to use any color, our tool uses standardized HTML Color Picker (https://developer.mozilla.org/en-US/docs/Web/HTML/Element/Input/color), how it looks and what it allows you to do may depend on your operating system or browser, look for some place where you can pick a custom color.
I've attached the screenshot how this looks like for myself, though it will likely look differently for you.