We present a theoretical framework in which gravitational mass emerges as a universal scalarmodulation of inertial mass, mediated by a dynamical field ϵ(x). The model preserves the WeakEquivalence Principle, remains ghost-free, is compatible with GW170817, and reproduces dark-matter– and dark-energy–like behavior without introducing particle species beyond the StandardModel. The field ϵ is identified as the dilaton associated with the spontaneous breaking of an ap-proximate scale symmetry, and the gravitational sector emerges via Sakharov-type induced gravity.We construct the full action, derive the equations of motion, discuss renormalization, and establishtheoretical consistency conditions including stability, positivity of energy, and screening. The re-sulting theory defines a unified and predictive alternative to GR+DM+DE that is testable throughastrophysical and cosmological observables.