Google Docs makes it easy to collaborate ... but it doesn't track the changes with any color coding. The editor must manually color-code to track changes while editing, whereas Suggesting mode ...

Following is a sampling of HTML color codes used in HTML tags for setting background and font color. Colors are coded as red, green and blue intensities in hexadecimal notation (see hex chart).

The entries that you input into your Google calendar can be edited to correspond to a color coding system of your own choosing. By default, your calendar entries will all display as the same color ...

Google Docs is a free word processing software ... "Custom" from the drop-down under "Page Color." You can input an HTML color code, for example, or play around with the tool to find a color ...