What I have:
I am using SharePoint Online from Office 365.
I've created a color coded SharePoint calendar using overlay.
What I want:
I want to use different colors for color coding than those proposed by SharePoint
(The current colors are very dark and not distinctive)
What I already know:
Changing anything in this version of SharePoint is very difficult as it is not supported by Microsoft.
I can't add a script web part in this version (as far as I know but it was checked thoroughly) and I am yet to find out how to add CSS customization without using third party software (which I can't do as I am the admin of only my site, not the organization)