01
70 / 25 / 5 Colour Ratio
70% primary greys (background, containers, nav). 25% white (card surfaces). 5% secondary accent colours (data, KPIs, highlights). Never let accent colours dominate the layout. This mirrors the Test Company Brand Hub colour ratio wheel exactly.
02
Semantic Colour Consistency
Green = always positive. Orange = always negative. Yellow = always warning. Purple = primary KPI. Blue = secondary/informational. Never swap these roles. Users must be able to read status from colour alone — backed by icons and labels for accessibility.
03
Typography Hierarchy
Segoe UI throughout. Two weights only: Regular (400) for body, Bold (700) for headings and values. Size contrast creates hierarchy — 36pt KPI vs 10pt label. Never use more than three sizes on one card.
04
WCAG 2.1 AA Compliance
All text/background combinations must achieve 4.5:1 contrast minimum. Never use Yellow as text colour. Never place Green on Light Grey. Always combine colour with a second indicator (arrow, icon, label) for colour-blind accessibility.
05
Chart Colour Strategy
Choose one strategy per report: A (Conservative — single Purple accent), B (Balanced — Purple + Blue primary), or C (Vibrant — full 5-colour sequence). Do not mix strategies within one report. Tints are approved for same-category sequential data only.
06
Power BI Theme First
Always import the theme JSON before building any report. This sets defaults for colours, fonts, and semantic values globally. Only override in the Format pane for specific visual requirements — never rebuild the palette manually from scratch.