  Using a general Ginzburg-Landau effective Lagrangian, we study the
topological structure and low-lying collective modes of dense QCD having both
chiral and diquark condensates, for two and three massless flavors. As we found
earlier, the QCD axial anomaly acts as an external field applied to the chiral
condensate in a color superconductor and, as a new critical point emerges,
leads to a crossover between the broken chiral symmetry and color
superconducting phases. At intermediate densities where both chiral and diquark
condensates are present, we derive a generalized Gell-Mann- Oakes-Renner
relation between the masses of pseudoscalar bosons and the magnitude of the
chiral and diquark-condensates. We show explicitly the continuity of the
ordinary pion at low densities to a generalized pion at high densities.
