I have this sage cell
x,y,z,t,u,v= var("x,y,z,t,u,v");
f(x,y)=9-x^2-y^2;
G=plot_vector_field(f.diff(), (x,-10,10), (y,-10,10), transparent=True, plot_points=12, color="brown", aspect_ratio=1);
G.axes_color((0,0,1));
show(G)
but I would like the tick color to match the blue axes color.
all help is appreciated.