Hi @fuzzy.beach,
Thanks for the feature request! Supernotes-flavored Markdown currently extends the original specification, as we’ve added additional functionalities such as checkboxes, highlighting, spoilers, and more.
Unfortunately, allowing for customizable extension of Markdown on a per-user basis is out of scope due to sharing and performance concerns.
Supernotes is a unified, accessible format for everyone. This means you can jump in, join, and edit other people’s cards instantly using the same Markdown format and shortcuts. Allowing for customizability means that cards might not render correctly on other people’s apps. Even without sharing, adding a few custom Markdown extensions could eventually slow down the editing experience.
However, if there are certain additional functionalities that are highly requested (such as the currently open colored text request), then we will try to find ways to add support for these in HTML, our Markdown flavor, or just visually within cards.