To address these challenges, several methods, such as integral equation theories, have been developed to provide an alternative that fills the gap between explicit solvent simulations and simple continuum treatment of solvation. In specific situations, hybrid methods that combine various levels of theoretical approaches may present the ideal trade-off between reliability and computational feasibility. Complicated systems in solutions tend to require not only large sizes but also long time scales, which makes simulations like AIMD and even MD computationally expensive. One way to make these calculations cheaper is modeling the system at the mesoscopic level. However, there are very few existing methods that describe the interaction between the molecular scale and mesoscale. Reduced solvation models, such as extended Born model 20 and COSMO, only describe the polarization of quantum mechanical region due to a change in dielectric. A major limitation of these models is that there is no mesoscale information. On the other hand, over the past two decades, classical Density Fucntional Theory (cDFT) and other related mesoscopic methods such as Poisson-Boltzmann Equation (PBE), smoothed particle hydrodynamics, and dissipative particle dynamics have garnered significant attention, in particular to model complex fluids such as suspensions, emulsions, and gels where the internal structure of the fluid is relevant to its macroscopic dynamics. cDFT combines accurate thermodynamics of bulk electrolyte solutions over a wide concentration range (up to 2M) with a high fidelity description of interfacial structure and forces that can be compared with state-of-the-art experimental observations.