# 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

- [配色盤 + WCAG 檢查器](https://www.teafun.cyou/tools/color-palette-wcag/) — 在本地檢查對比度、AA/AAA 合規、產生配色盤變體，並匯出 CSS 或 Tailwind v4 色彩 token。
- [色盲測試](https://www.teafun.cyou/tools/colorblind/) — 使用專為玩家優化的石原色盲測試圖，檢測您的色覺。
- [長寬比計算器](https://www.teafun.cyou/tools/aspect-ratio/) — 即時計算長寬比。轉換尺寸、求缺失邊長，並查看 2025/2026 最新社群媒體圖片尺寸。

## 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.