static int red = 0.00f
static int green = 0.00f
static int blue = 0.00f
static int aplha = 1.00f
style.Colors[ImGuiCol_WindowBg] = ImVec4(red, green, blue, aplha); //Цвет бекраунда
ImGui::SliderFloat("##Red", &red, 0.00f, 1.00f, "Red: %.2f");
ImGui::SliderFloat("##Green", &green, 0.000f, 1.000f, "Green: %.2f");
ImGui::SliderFloat("##Blue", &blue, 0.00f, 1.00f, "Blue: %.2f");
ImGui::SliderFloat("##Alpha", &alpha, 0.00f, 1.00f, "Alpha: %.2f");