Improve codebase consistency

[Reinachan]

While I was working on the project, I changed my mind several times and made some shortcuts here and there to get the project out on time. This means it's not always clear from looking at other components how things are supposed to be done.

Completion criteria

• Update colours to follow a similar format to kitsuawards-judges-form
• Define all components in one consistent way according to the contribution guidelines
• Add index re-exports