rendering requirements

docs/requirements.md

@@ -9,6 +9,7 @@ Config files use the TOML format. The following config files drive game paramete
 - **recipes.toml** — crafting recipes: inputs, outputs, quantities, durations, and reprocessing plant probabilities.
 - **ships.toml** — ship stats (HP, speed, damage, attack range, attack rate, sensor range) as formulas of ship level, required materials per blueprint, threat cost formula, and whether each blueprint is available from the start or unlocked via loot.
 - **stations.toml** — HP, damage, range, fire rate, and scrap drop for player and enemy defence stations, defined as formulas of station level.
+- **visuals.toml** — rendering-only config (not game parameters): fill and outline colors, glyphs, and tile tints for every building type, item type, ship role, and station type; beam color and width; overlay and toast colors. Loaded by the UI at startup; the simulation does not read it.
 
 ### Surface Mask Format