Hi Robert,

Generally the applications in the platform (such as calendar) are fixed in their layout and design to facilitate ease of use. As a result the place where you have the most control over the content layout and colour is through the pages you create with the content management system. 

However, it is possible to make the change you would like via the custom CSS you can add to your theme. This is not something that someone non-technical should try. 

If you have some experience of CSS then please look up the classes that surround the text you want to change and upload custom CSS through the theme pages to make the changes you need. 

If you are not familiar with the use of CSS then unfortunately there isn't anyway you can change the text colour in the calendar application.