  The properties of dense QCD matter are delineated through the construction of
equations of state which should be consistent with the low and high density
limits of QCD, nuclear laboratory experiments, and the neutron star
observations. These constraints, together with the causality condition of the
sound velocity, are used to develop the picture of hadron-quark continuity in
which hadronic matter continuously transforms into quark matter (modulo small
1st order phase transitions). The resultant unified equation of state at zero
temperature and $\beta$-equilibrium, which we call Quark-Hadron-Crossover
(QHC19), is consistent with the measured properties of neutron stars as well as
the microphysics known for the hadron phenomenology. In particular to $\sim
10n_0$ ($n_0$: saturation density) the gluons remain as non-perturbative as in
vacuum and the strangeness can be as abundant as up- and down-quarks at the
core of two-solar mass neutron stars. Within our modeling the maximum mass is
found less than $\simeq 2.35$ times solar mass and the baryon density at the
core ranges in $\sim 5$-8$n_0$.
