# Typography (L0004) delivered; advanced to colour (L0005)

User confirmed L0004 (typography fundamentals) was understood and asked for the next lesson. No drill requested for typography, so no L0004-drill lesson built. If retention proves shaky later, build a typography drill modelled on L0002.

Lesson 0005 covers colour fundamentals: HSL (hue, saturation, lightness), the neutral-scale workhorse, accent + 3 semantic colours, and the three data-viz palette types (sequential, diverging, categorical). Worked example uses a Holistics KPI dashboard. Five practice exercises with hidden reveals.

Glossary state after this lesson: 4 untagged colour terms (hue, saturation, value) were upgraded to L0005 and 7 new colour terms added (HSL, neutral scale, accent colour, semantic colour, sequential / diverging / categorical palettes). 35 cards total in flashcards.html; new cards land in Box 1 automatically thanks to the backfill in `loadState()`.

Mission alignment: colour is the second-highest-leverage chapter for the Holistics communication mission, after hierarchy. With CRAP + hierarchy + typography + colour in place, the next lesson (composition / putting it all together to design a real diagram from scratch) should be a synthesis project rather than new vocabulary.