Hey, so if you ever wanted the same great GUI as Undeck has, it's fairly simple to edit it. First, get smef's or some other indigo source.
Navigate to Gui.cpp and find lines starting with style.
Next, replace ALL the lines with the following code:
Code:
	style.WindowPadding = ImVec2(15, 15);
	style.WindowRounding = 5.0f;
	style.FramePadding = ImVec2(5, 5);
	style.FrameRounding = 4.0f;
	style.ItemSpacing = ImVec2(12, 8);
	style.ItemInnerSpacing = ImVec2(8, 6);
	style.IndentSpacing = 25.0f;
	style.ScrollbarSize = 15.0f;
	style.ScrollbarRounding = 9.0f;
	style.GrabMinSize = 5.0f;
	style.GrabRounding = 3.0f;
(Of course, not all in the code but just those which are in lines 35 - 60.
Next, we will navigate to some of the shemes, I chose MainSheme(if you use default indigo use RedSheme probably)
Code:
void CGui::MainSheme()
{
	ImGuiStyle& style = ImGui::GetStyle();

	style.Colors[ImGuiCol_Text] = ImVec4(0.80f, 0.80f, 0.83f, 1.00f);
	style.Colors[ImGuiCol_TextDisabled] = ImVec4(0.24f, 0.23f, 0.29f, 1.00f);
	style.Colors[ImGuiCol_WindowBg] = ImVec4(0.06f, 0.05f, 0.07f, 1.00f);
	style.Colors[ImGuiCol_ChildWindowBg] = ImVec4(0.07f, 0.07f, 0.09f, 1.00f);
	style.Colors[ImGuiCol_PopupBg] = ImVec4(0.07f, 0.07f, 0.09f, 1.00f);
	style.Colors[ImGuiCol_Border] = ImVec4(0.80f, 0.80f, 0.83f, 0.88f);
	style.Colors[ImGuiCol_BorderShadow] = ImVec4(0.92f, 0.91f, 0.88f, 0.00f);
	style.Colors[ImGuiCol_FrameBg] = ImVec4(0.10f, 0.09f, 0.12f, 1.00f);
	style.Colors[ImGuiCol_FrameBgHovered] = ImVec4(0.24f, 0.23f, 0.29f, 1.00f);
	style.Colors[ImGuiCol_FrameBgActive] = ImVec4(0.56f, 0.56f, 0.58f, 1.00f);
	style.Colors[ImGuiCol_TitleBg] = ImVec4(0.10f, 0.09f, 0.12f, 1.00f);
	style.Colors[ImGuiCol_TitleBgCollapsed] = ImVec4(1.00f, 0.98f, 0.95f, 0.75f);
	style.Colors[ImGuiCol_TitleBgActive] = ImVec4(0.07f, 0.07f, 0.09f, 1.00f);
	style.Colors[ImGuiCol_MenuBarBg] = ImVec4(0.10f, 0.09f, 0.12f, 1.00f);
	style.Colors[ImGuiCol_ScrollbarBg] = ImVec4(0.10f, 0.09f, 0.12f, 1.00f);
	style.Colors[ImGuiCol_ScrollbarGrab] = ImVec4(0.80f, 0.80f, 0.83f, 0.31f);
	style.Colors[ImGuiCol_ScrollbarGrabHovered] = ImVec4(0.56f, 0.56f, 0.58f, 1.00f);
	style.Colors[ImGuiCol_ScrollbarGrabActive] = ImVec4(0.06f, 0.05f, 0.07f, 1.00f);
	style.Colors[ImGuiCol_ComboBg] = ImVec4(0.19f, 0.18f, 0.21f, 1.00f);
	style.Colors[ImGuiCol_CheckMark] = ImVec4(0.80f, 0.80f, 0.83f, 0.31f);
	style.Colors[ImGuiCol_SliderGrab] = ImVec4(0.80f, 0.80f, 0.83f, 0.31f);
	style.Colors[ImGuiCol_SliderGrabActive] = ImVec4(0.06f, 0.05f, 0.07f, 1.00f);
	style.Colors[ImGuiCol_Button] = ImVec4(0.10f, 0.09f, 0.12f, 1.00f);
	style.Colors[ImGuiCol_ButtonHovered] = ImVec4(0.24f, 0.23f, 0.29f, 1.00f);
	style.Colors[ImGuiCol_ButtonActive] = ImVec4(0.56f, 0.56f, 0.58f, 1.00f);
	style.Colors[ImGuiCol_Header] = ImVec4(0.10f, 0.09f, 0.12f, 1.00f);
	style.Colors[ImGuiCol_HeaderHovered] = ImVec4(0.56f, 0.56f, 0.58f, 1.00f);
	style.Colors[ImGuiCol_HeaderActive] = ImVec4(0.06f, 0.05f, 0.07f, 1.00f);
	style.Colors[ImGuiCol_Column] = ImVec4(0.56f, 0.56f, 0.58f, 1.00f);
	style.Colors[ImGuiCol_ColumnHovered] = ImVec4(0.24f, 0.23f, 0.29f, 1.00f);
	style.Colors[ImGuiCol_ColumnActive] = ImVec4(0.56f, 0.56f, 0.58f, 1.00f);
	style.Colors[ImGuiCol_ResizeGrip] = ImVec4(0.00f, 0.00f, 0.00f, 0.00f);
	style.Colors[ImGuiCol_ResizeGripHovered] = ImVec4(0.56f, 0.56f, 0.58f, 1.00f);
	style.Colors[ImGuiCol_ResizeGripActive] = ImVec4(0.06f, 0.05f, 0.07f, 1.00f);
	style.Colors[ImGuiCol_CloseButton] = ImVec4(0.40f, 0.39f, 0.38f, 0.16f);
	style.Colors[ImGuiCol_CloseButtonHovered] = ImVec4(0.40f, 0.39f, 0.38f, 0.39f);
	style.Colors[ImGuiCol_CloseButtonActive] = ImVec4(0.40f, 0.39f, 0.38f, 1.00f);
	style.Colors[ImGuiCol_PlotLines] = ImVec4(0.40f, 0.39f, 0.38f, 0.63f);
	style.Colors[ImGuiCol_PlotLinesHovered] = ImVec4(0.25f, 1.00f, 0.00f, 1.00f);
	style.Colors[ImGuiCol_PlotHistogram] = ImVec4(0.40f, 0.39f, 0.38f, 0.63f);
	style.Colors[ImGuiCol_PlotHistogramHovered] = ImVec4(0.25f, 1.00f, 0.00f, 1.00f);
	style.Colors[ImGuiCol_TextSelectedBg] = ImVec4(0.25f, 1.00f, 0.00f, 0.43f);
	style.Colors[ImGuiCol_ModalWindowDarkening] = ImVec4(1.00f, 0.98f, 0.95f, 0.73f);
}
The following code will give you the cool looks of my Undeck Lite paste.
Happy pasting!