Hi @Nilesh_Mali
You can't use gradients directly with the OOTB color picker because gradients are not colors but a CSS property.For example:
background: rgb(0,0,0);
background: linear-gradient(90deg, rgba(0,0,0,1) 0%, rgba(246,253,29,0.6097032563025211) 42%, rgba(148,171,249,0.8085828081232493) 85%...