  We study color superconductivity with $N_f=1,2,$ and 3 massless flavors of
quarks. We present a general formalism to derive and solve the gap equations
for condensation in the even-parity channel. This formalism shows that the
leading-order contribution to the gap equation is unique for all color
superconductors studied here, and that differences arise solely at the
subleading order. We discuss a simple method to compute subleading
contributions from the integration over gluon momenta in the gap equation.
Subleading contributions enter the prefactor of the color-superconducting gap
parameter. In the case of color-flavor and color-spin locking we identify
further corrections to this prefactor arising from the two-gap structure of the
quasiparticle excitations. Computing the transition temperature, $T_c$, where
the color-superconducting condensate melts, we find that these contributions
lead to deviations from the BCS behavior $T_c\simeq 0.57 \phi_0$, where
$\phi_0$ is the magnitude of the zero-temperature gap at the Fermi surface.
