In this colloquium, on the established platforms of quantum field theory and density functional theory, we summarize the properties of interacting light and matters that we plan to calculate. To analyze various quantum mechanical natures of solid states, theorists and experimentalists have always examined the spin or magnetization, the charge density or polarization, and the Berry curvature or orbital momenta. Our research focuses on the light-excited states of solids, putting particular emphasis on first-principles computations of nonlinear optical responses associated with those materials properties. We wish our progress of the first-principles computation methods toward a full quantum mechanical mixture of materials and nearfield electromagnetism leads to an effective and reliable bridge that connects pure theories and experimental observations.