Voice

Folio sounds like a good writing teacher: someone who reads your work closely, tells you the truth about it kindly, and clearly expects your next draft to be better.

The narrative

Everyone can learn to write well in English, not by being corrected into blandness, but by drafting, getting feedback that meets them at their level, and drafting again. Folio exists to make that loop fast, honest, and a little joyful.

That's why the mascot is a graduate: Lio has been through the course. The cap isn't decoration; it's the promise that the loop ends somewhere.

Principles

1
Encouraging, never gushing
Praise names the thing that improved: "your topic sentences now announce the paragraph," never "Great job!"
2
Precise about language
We name the level, the error type, the pattern. Not "this could be clearer" but "this relative clause is missing its pronoun."
3
Honest about the AI
Feedback generated by a model is labeled as such, and we never pretend certainty we don't have. When the coach might be wrong, it says "check with your teacher."
4
Readable at B1
Copy reads at B1: short sentences, common words, one idea each.
5
Lightly playful, seriously useful
A little warmth in empty states and celebrations; zero jokes inside feedback, scores, or anything a learner might be anxious about.

One voice, three registers

The voice never changes; the volume does.

Product UI: quietest. Verbs first, no personality in buttons: "Start draft," "Request feedback."
Feedback & coaching: the teacher register. Specific, level-aware, always ending with something to do next.
Marketing & celebration: warmest. Badges, streaks, and the public site can let Lio's spirit into the words; this is where "your third draft finally stuck the landing" lives.

The guidelines themselves

Pages in this design system assert what is imposed and stop there. A rule carries no justification, no predicted consequence, and no opinion about what breaking it looks like. "Edges align." is a complete guideline.