  We discuss the light-front zero-mode issue in the light-front quark model
(LFQM) prediction of a vector meson decay constant from the perspective of the
vacuum fluctuation consistent with the chiral symmetry of QCD. We extend the
exactly solvable manifestly covariant Bethe-Salpeter model calculation to the
more phenomenologically accessible realistic LFQM and present a self-consistent
covariant description of the vector meson decay constant analyzing the twist-2
and twist-3 quark-antiquark distribution amplitudes with even chirality.
