# Design & Color Tools

> Check color contrast ratios for WCAG compliance, simulate color blindness, and calculate aspect ratios — free design helpers that run entirely in your browser.

## Tools in this collection

- [Palette de couleurs + vérificateur WCAG](https://www.teafun.cyou/tools/color-palette-wcag/) — Vérifiez les ratios de contraste, la conformité AA/AAA, générez des variantes de palette et exportez des jetons de couleur CSS ou Tailwind v4 localement.
- [Test de daltonisme](https://www.teafun.cyou/tools/colorblind/) — Testez votre vision des couleurs à l'aide de planches de type Ishihara spécialement conçues pour les gamers.
- [Calculateur de Format d'Image](https://www.teafun.cyou/tools/aspect-ratio/) — Calculez les formats d'image instantanement. Convertissez des dimensions, resolvez les cotes manquants et consultez les tailles d'images pour reseaux sociaux 2025/2026.

## FAQ

### Which contrast ratio do I need to pass WCAG AA?

Normal text requires a 4.5:1 ratio; large text (18pt+ or 14pt bold) requires 3:1. The WCAG Color Contrast checker shows both thresholds and your pass/fail status instantly.

### How does the color blindness simulator work?

It applies standard daltonisation matrices to the input colors to approximate how they appear with different types of color vision deficiency — all computed locally in your browser.

### Should colour ever be the only way I show information?

No. Because some users cannot distinguish certain colours, pair every colour cue with a second signal — a label, an icon, a pattern, or text. The simulator helps you check whether your meaning survives when the colour does not.

### Why does aspect ratio matter for images and video?

Cropping or resizing to the wrong ratio either distorts the content or forces letterboxing. Locking to a standard ratio like 16:9 or 1:1 keeps everything in proportion and predictable across the places it will be displayed.