# 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

- [调色板 + WCAG 检查器](https://www.teafun.cyou/tools/color-palette-wcag/) — 本地检查对比度、AA/AAA 合规、生成 palette 变体，并导出 CSS 或 Tailwind v4 色彩 token。
- [色盲测试](https://www.teafun.cyou/tools/colorblind/) — 使用专为游戏玩家优化的石原色觉测试图，检测您的色觉。
- [长宽比计算器](https://www.teafun.cyou/tools/aspect-ratio/) — 即时计算长宽比。转换尺寸、求缺失边长，并查看 2025/2026 最新社交媒体图片尺寸。

## 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.