Changing definecolor{lime}{HTML}{A6CE39} statement to a newcommand statement

I am using Springer journals template (SVJour3). The template says that do not use def but
use newcommand{}{} to make your own definitions.

I had a statement definecolor{lime}{HTML}{A6CE39} which I use in the following context for making an Orcid icon:

definecolor{lime}{HTML}{A6CE39}
DeclareRobustCommand{orcidicon}{%
    begin{tikzpicture}
    draw[lime, fill=lime] (0,0) 
    circle [radius=0.16] 
    node[white] {{fontfamily{qag}selectfont tiny ID}};
    draw[white, fill=white] (-0.0625,0.095) 
    circle [radius=0.007];
    end{tikzpicture}
    hspace{-2mm}
}

I need to change the statement definecolor{lime}{HTML}{A6CE39} with a newcommand instead of the def statement. Your suggestions is highly appreciated?