raatools/

🎨 Design / CSS

CSS-Generatoren, Farbpaletten, Seitenverhältnis- und Bildschirm-DPI-Rechner

Colour, proportion and asset tools for the point in a design where you need a number rather than an opinion. Building a palette, checking an aspect ratio, working out real screen density, and generating favicons.

These lean toward the mechanical end of design work — the parts with defensible right answers, like whether two colours pass contrast or what 1920×1080 reduces to.

Which tool do I want?

If you…Use
You are building a colour schemeFarbpaletten-Generator
You need a ratio simplified or dimensions that match oneSeitenverhältnis-Rechner
You want the true DPI of a displayBildschirm-DPI-Rechner
You need favicons in the right sizesFavicon-Generator

Contrast ratio is about luminance, not how different colours look

Two colours can sit far apart on a colour wheel and still fail accessibility. WCAG contrast is computed from relative luminance, which weights green far more heavily than red and red more than blue — so mid-blue text on a mid-red background looks vividly different and can fall below the 4.5:1 minimum for body text.

The practical consequence is that you cannot judge contrast by eye, especially on a bright calibrated monitor. Measure it. Body text needs 4.5:1; large text, meaning roughly 24px or 19px bold and above, needs 3:1; and interface components and focus indicators need 3:1 against what surrounds them.

Yellow is the usual casualty. Yellow on white almost never passes, however saturated, because both are high-luminance. Darkening the yellow toward amber fixes it while keeping the hue.