Neutralize strong colors

My client has a fixed branding color schema, so I can't change its colors. He asked me to design an accordion component, where the header part is going to be blue color and in the header, I should put a piece of color information about the product it holds. The colors don't match with each other, the header has blue and the product has red, green, yellow colors. I've tried different iteration, but honestly, they suck. No matter how I combine them (borders, shadow) they hurt my eyes. Any idea how can I "neutralize" those colors?