  Basing on a semiclassical picture of dyons, we present a nonperturbative
model of a pure Yang--Mills theory at any temperatures, for an arbitrary simple
gauge group. We argue that at low temperatures dyons drive the Yang--Mills
system for all groups to a phase where the `eigenphases' of the Polyakov line
are, as a vector, proportional to the Weyl vector being the half sum of
positive roots. For most gauge groups it means confinement, in particular for
`quarks' in any N-ality nonzero representation of the SU(N) gauge group. At a
critical temperature there is a 1st order phase transition for all groups
(except SU(2) where the transition is 2nd order), characterized by a jump of
Polyakov lines, irrespectively of whether the gauge group has a nontrivial
center, or not.

High Energy Physics - Theory;High Energy Physics - Lattice