  We present a QCD bound-state calculation based on a renormalization
group-improved light-front Hamiltonian formalism. The QCD Hamiltonian is
determined to second order in the coupling, and it includes two-body confining
interactions. We make a momentum expansion, obtaining an equal-time-like
Schrodinger equation. This is solved for quark-antiquark constituent states,
and we obtain a set of self-consistent parameters by fitting B mesons. Applying
the approach to charmonium spectra leads to a prediction of the hyperfine
splitting between J/$\psi$(1S) and $\eta_c$(1S) which is in good agreement with
experiment.
