diff --git a/libs/ardour/ardour/lv2_plugin.h b/libs/ardour/ardour/lv2_plugin.h
index 6682eed252..11c9e7ee66 100644
--- a/libs/ardour/ardour/lv2_plugin.h
+++ b/libs/ardour/ardour/lv2_plugin.h
@@ -182,9 +182,18 @@ class LIBARDOUR_API LV2Plugin : public ARDOUR::Plugin, public ARDOUR::Workee
 	static void set_global_ui_foreground_color (uint32_t c) {
 		_ui_foreground_color = c;
 	}
+	static void set_global_ui_contrasting_color (uint32_t c) {
+		_ui_contrasting_color = c;
+	}
 	static void set_global_ui_scale_factor (float s) {
 		_ui_scale_factor = s;
 	}
+	static void set_global_ui_style_boxy (bool yn) {
+		_ui_style_boxy = yn;
+	}
+	static void set_global_ui_style_flat (bool yn) {
+		_ui_style_flat = yn;
+	}
 	static void set_main_window_id (unsigned long id) {
 		_ui_transient_win_id = id;
 	}
@@ -336,8 +345,11 @@ class LIBARDOUR_API LV2Plugin : public ARDOUR::Plugin, public ARDOUR::Workee
 
 	// Options passed to plugin
 	int32_t              _seq_size;
+	static bool          _ui_style_flat;
+	static bool          _ui_style_boxy;
 	static uint32_t      _ui_background_color;
 	static uint32_t      _ui_foreground_color;
+	static uint32_t      _ui_contrasting_color;
 	static float         _ui_scale_factor;
 	static unsigned long _ui_transient_win_id;
 
diff --git a/libs/ardour/lv2_plugin.cc b/libs/ardour/lv2_plugin.cc
index 24e08ac1c6..c2fc0f432e 100644
--- a/libs/ardour/lv2_plugin.cc
+++ b/libs/ardour/lv2_plugin.cc
@@ -128,11 +128,14 @@ using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
 
-bool          LV2Plugin::force_state_save = false;
-uint32_t      LV2Plugin::_ui_background_color = 0x000000ff; // RGBA
-uint32_t      LV2Plugin::_ui_foreground_color = 0xffffffff; // RGBA
-float         LV2Plugin::_ui_scale_factor = 1.0;
-unsigned long LV2Plugin::_ui_transient_win_id = 0;
+bool          LV2Plugin::force_state_save      = false;
+bool          LV2Plugin::_ui_style_flat        = false;
+bool          LV2Plugin::_ui_style_boxy        = false;
+uint32_t      LV2Plugin::_ui_background_color  = 0x000000ff; // RGBA
+uint32_t      LV2Plugin::_ui_foreground_color  = 0xffffffff; // RGBA
+uint32_t      LV2Plugin::_ui_contrasting_color = 0x33ff33ff; // RGBA
+float         LV2Plugin::_ui_scale_factor      = 1.0;
+unsigned long LV2Plugin::_ui_transient_win_id  = 0;
 
 class LV2World : boost::noncopyable {
 public:
@@ -533,6 +536,7 @@ LV2Plugin::init(const void* c_plugin, samplecnt_t rate)
 #endif
 
 	LV2_URID atom_Int   = _uri_map.uri_to_id(LV2_ATOM__Int);
+	LV2_URID atom_Bool  = _uri_map.uri_to_id(LV2_ATOM__Bool);
 	LV2_URID atom_Long  = _uri_map.uri_to_id(LV2_ATOM__Long);
 	LV2_URID atom_Float = _uri_map.uri_to_id(LV2_ATOM__Float);
 
@@ -566,8 +570,14 @@ LV2Plugin::init(const void* c_plugin, samplecnt_t rate)
 		  sizeof(int32_t), atom_Int, &_ui_background_color },
 		{ LV2_OPTIONS_INSTANCE, 0, _uri_map.uri_to_id("http://lv2plug.in/ns/extensions/ui#foregroundColor"),
 		  sizeof(int32_t), atom_Int, &_ui_foreground_color },
+		{ LV2_OPTIONS_INSTANCE, 0, _uri_map.uri_to_id("http://lv2plug.in/ns/extensions/ui#contrastingColor"),
+		  sizeof(int32_t), atom_Int, &_ui_contrasting_color },
 		{ LV2_OPTIONS_INSTANCE, 0, _uri_map.uri_to_id("http://lv2plug.in/ns/extensions/ui#scaleFactor"),
 		  sizeof(float), atom_Float, &_ui_scale_factor },
+		{ LV2_OPTIONS_INSTANCE, 0, _uri_map.uri_to_id("http://ardour.org/lv2/theme/#styleBoxy"),
+		  sizeof(float), atom_Bool, &_ui_style_boxy },
+		{ LV2_OPTIONS_INSTANCE, 0, _uri_map.uri_to_id("http://ardour.org/lv2/theme/#styleFlat"),
+		  sizeof(float), atom_Bool, &_ui_style_flat },
 		{ LV2_OPTIONS_INSTANCE, 0, _uri_map.uri_to_id("http://kxstudio.sf.net/ns/lv2ext/props#TransientWindowId"),
 		  sizeof(int32_t), atom_Long, &_ui_transient_win_id },
 		{ LV2_OPTIONS_INSTANCE, 0, 0, 0, 0, NULL }