Colour
Colour has a job before it has a mood
A useful web palette defines surfaces, text, action and state. Each pair still needs enough contrast when the screen is dim, small or viewed outdoors.
Start with roles
Separate the main surface, raised surface, primary text, secondary text, action and status colours. A brand colour does not have to carry body copy simply because it appears in the logo.
Contrast is measurable
Regular text needs a contrast ratio of at least 4.5:1 for WCAG AA. Large text needs at least 3:1. Interface graphics and focus indicators also need sufficient separation from their surroundings.
A scale is not a palette by itself
Lighter and darker versions are useful for states and surfaces, but the final selection depends on context. A tool can calculate a ratio; it cannot decide which element should command attention.
The working contrast checker and colour scale are available on the paired Serbian tool page. Values are processed locally in the browser.