Is there a source where to find secondary and tertiary colors combination?

HTML-CSS
1

it’s very smooth and cool to use that kind of colors expetially for the UX, i don’t know how else to phrase, i hope someone can help.

2

The one I normally used to always use was

https://paletton.com/

Adobe’s colour palette generator is good, and the mobile app (Adobe Capture CC) is great.

https://color.adobe.com/create/color-wheel/

There are a load of others (Google “colour palette generator”), most have a way to generate standard combinations.

https://color.adobe.com/create/color-wheel/

Adobe Illustrator has one built in