Vc pode adicinar uma função para mudar a cor do painel?
static ParticleSystem particleSystem(150, 0.05f);
static auto lastTime = std::chrono::high_resolution_clock::now();
void ApplyBlueTheme() {
    ImGui::StyleColorsDark();

    ImGuiStyle& style = ImGui::GetStyle();
    ImVec4* colors = style.Colors;

    // Vermelho bonito e branco
    const ImVec4 red_custom(0.85f, 0.10f, 0.10f, 1.0f); 
    const ImVec4 white_color(1.0f, 1.0f, 1.0f, 1.0f);  
    const ImVec4 dark_bg(0.10f, 0.10f, 0.10f, 1.0f);   

    colors[ImGuiCol_WindowBg]        = dark_bg;
    colors[ImGuiCol_ChildBg]         = dark_bg;

    colors[ImGuiCol_TitleBg]         = red_custom;
    colors[ImGuiCol_TitleBgActive]   = red_custom;
    colors[ImGuiCol_TitleBgCollapsed]= red_custom;

    colors[ImGuiCol_Button]          = red_custom;
    colors[ImGuiCol_ButtonHovered]   = ImVec4(1.0f, 0.20f, 0.20f, 1.0f);
    colors[ImGuiCol_ButtonActive]    = ImVec4(0.70f, 0.05f, 0.05f, 1.0f); 

    colors[ImGuiCol_Header]          = red_custom;
    colors[ImGuiCol_HeaderHovered]   = ImVec4(1.0f, 0.20f, 0.20f, 1.0f);
    colors[ImGuiCol_HeaderActive]    = ImVec4(0.70f, 0.05f, 0.05f, 1.0f);

    colors[ImGuiCol_FrameBg]         = ImVec4(0.15f, 0.15f, 0.15f, 1.0f);
    colors[ImGuiCol_FrameBgHovered]  = red_custom;
    colors[ImGuiCol_FrameBgActive]   = red_custom;

    colors[ImGuiCol_SliderGrab]      = red_custom;
    colors[ImGuiCol_SliderGrabActive]= ImVec4(0.70f, 0.05f, 0.05f, 1.0f);

    colors[ImGuiCol_CheckMark]       = white_color; 
    colors[ImGuiCol_Text]            = white_color; 

    colors[ImGuiCol_Border]       = ImVec4(0.0f, 0.0f, 0.0f, 0.0f);
    colors[ImGuiCol_BorderShadow] = ImVec4(0.0f, 0.0f, 0.0f, 0.0f);

    style.WindowBorderSize = 0.0f;
    style.FrameBorderSize  = 0.0f;
    style.TabBorderSize    = 0.0f;

    style.FrameRounding = 10.0f;
    style.GrabRounding = 12.0f;
    style.WindowRounding = 15.0f;
    style.PopupRounding = 8.0f;
    style.ScrollbarRounding = 8.0f;
    style.TabRounding = 8.0f;
    style.GrabMinSize = 15.0f;

    style.WindowTitleAlign = ImVec2(0.5f, 0.5f);
    style.WindowMenuButtonPosition = ImGuiDir_Left;
    style.DisplaySafeAreaPadding = ImVec2(4, 4);
    style.FramePadding = ImVec2(10, 6);
    style.ItemSpacing = ImVec2(8, 4);
    style.ItemInnerSpacing = ImVec2(8, 6);
    style.IndentSpacing = 25.0f;
    style.ScrollbarSize = 20.0f;
}

void menu() {
    static bool IsBall = true;
    static float ANIM_SPEED = 0.25f;
    static float Velua = IsBall ? 0.0f : 1.0f;
    Velua = ImClamp(Velua + (ImGui::GetIO().DeltaTime / ANIM_SPEED) * (IsBall ? 1.0f : -1.0f), 0.0f, 1.0f);

    ImVec4 startColor = ImColor(0.0f, 0.094f, 0.282f, 1.0f);
    ImVec4 endColor   = ImColor(0.0f, 0.2f, 0.5f, 1.0f);
    ImVec4 currentColor = ImLerp(startColor, endColor, Velua);

    ImVec2 windowSize = ImVec2(500 * Velua, 370 * Velua);

    if (Velua > 0.0f) {
        ImGui::SetNextWindowSize(windowSize, ImGuiCond_Always);
        ImGui::PushStyleColor(ImGuiCol_WindowBg, currentColor);
        ImGui::PushStyleColor(ImGuiCol_ChildBg, currentColor);
    }

    ApplyBlueTheme();

    static int activeTab = 1;
    static bool KeyBindTest = false; 

    if (init) {
        if (ImGui::Begin("LEO MODZ VIP APK MOD", &init, ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoScrollbar)) {

            if (ImGui::Button("AIMBOT", ImVec2(150, 50))) activeTab = 1;
            ImGui::SameLine();
            if (ImGui::Button("VISUAL", ImVec2(150, 50))) activeTab = 2;
            ImGui::SameLine();
            if (ImGui::Button("OUTROS", ImVec2(150, 50))) activeTab = 3;

            ImGui::Separator();

            ImGui::BeginChild("ChildContent", ImVec2(-1, -1), false);

            if (activeTab == 1) {
                ImGui::Checkbox("ATIVAR FUNÇOES", &AimbotEsp);
                ImGui::Checkbox("AIMBOT TIRO", &Aimbot);
           //     ImGui::Checkbox("AIM VISIBLE", &AimVisible);

                ImGui::SliderInt("AIM FOV", &Fov, 0, 1000);
            }

            if (activeTab == 2) {
                ImGui::Checkbox("ESP LINE", &EspLine);
                ImGui::Checkbox("ESP BOX", &EspBox);
                ImGui::Checkbox("ESP VIDA", &EspVida);
                ImGui::Checkbox("ESP FOV", &EspCircle);
            }

            if (activeTab == 3) {
               ImGui::Checkbox("KEY BIND CHEATS", &KeyBindTest);
                ImGui::Checkbox("RESET GUEST", &ResetGuest1);
            }

            ImGui::EndChild();
        }
        ImGui::End();
    }

    if (KeyBindTest) {
        ImGui::SetNextWindowSize(ImVec2(300, 200), ImGuiCond_FirstUseEver);
        ImGui::Begin("FUNÇÕES CHEATS", NULL, ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoResize);
        ImGui::Checkbox("SPEED TIMER", &SpeedHack);
        ImGui::C
heckbox("GHOST HACK", &GhostHack);
        ImGui::End();
    }

    if (Velua > 0.0f) {
        ImGui::PopStyleColor(2);
    }
}