  We determine the chiral phase structure of $2+1$-flavour QCD in dependence of
temperature and the light flavour quark mass with Dyson-Schwinger equations.
Specifically, we compute the renormalised chiral condensate and its
susceptibility. The latter is used to determine the (pseudo)critical
temperature for general light current quark masses. In the chiral limit we
obtain a critical temperature of about 141\,MeV. This result is in quantitative
agreement with recent functional renormalisation group results in QCD, and is
compatible with the respective lattice results. We also compute the order
parameter potential of the light chiral condensate and map out the regime in
the phase diagram which exhibits quasi-massless modes, and discuss the
respective chiral dynamics.
