raatools/

🎨 Design / CSS

Generadores CSS, paletas de colores, calculadoras de relación de aspecto y DPI

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 schemeGenerador de paletas de colores
You need a ratio simplified or dimensions that match oneCalculadora de relación de aspecto
You want the true DPI of a displayCalculadora de DPI de pantalla
You need favicons in the right sizesGenerador de Favicon

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.