diff --git a/lib/ugui.c3l/src/ugui_cmd.c3 b/lib/ugui.c3l/src/ugui_cmd.c3
index 2919436..3bd2d0d 100644
--- a/lib/ugui.c3l/src/ugui_cmd.c3
+++ b/lib/ugui.c3l/src/ugui_cmd.c3
@@ -14,6 +14,7 @@ enum CmdType {
 // command to draw a rect
 struct CmdRect {
 	Rect rect;
+	ushort thickness;
 	ushort radius;
 	Color color;
 }
@@ -104,6 +105,7 @@ fn void? Ctx.push_rect(&ctx, Rect rect, int z_index, Style* style)
 			.rect.rect = rect,
 			.rect.color = border_color,
 			.rect.radius = radius,
+			.rect.thickness = border.x,
 		};
 		ctx.push_cmd(&cmd, z_index)!;
 	}
@@ -118,6 +120,7 @@ fn void? Ctx.push_rect(&ctx, Rect rect, int z_index, Style* style)
 		},
 		.rect.color = bg,
 		.rect.radius = radius,
+		.rect.thickness = max(rect.w, rect.h),
 	};
 	if (cull_rect(cmd.rect.rect, ctx.div_scissor)) return;
 	ctx.push_cmd(&cmd, z_index)!;
diff --git a/resources/shaders/source/rect.frag.glsl b/resources/shaders/source/rect.frag.glsl
index 4ae4ea4..5c5e5c1 100644
--- a/resources/shaders/source/rect.frag.glsl
+++ b/resources/shaders/source/rect.frag.glsl
@@ -7,6 +7,7 @@ layout(set = 3, binding = 0) uniform Viewport {
 layout(location = 0) in vec4 in_color;
 layout(location = 1) in vec4 in_quad_size; // x,y, w,h
 layout(location = 2) in float in_radius;
+layout(location = 3) in float thickness;
 
 layout(location = 0) out vec4 fragColor;
 
@@ -16,12 +17,16 @@ float sdf_rr(vec2 p, vec2 half_size, float radius) {
     return length(max(q, 0.0)) + min(max(q.x, q.y), 0.0) - radius;
 }
 
+const float smoothness = 1.5;
+
 void main()
 {
     vec2 centerpoint = in_quad_size.xy + in_quad_size.zw * 0.5;
     vec2 half_size = in_quad_size.zw * 0.5;
-    float distance = sdf_rr(vec2(gl_FragCoord) - centerpoint, half_size, in_radius);
-    float alpha = 1.0 - smoothstep(0.0, 1.5, distance);
+    float distance = -sdf_rr(vec2(gl_FragCoord) - centerpoint, half_size, in_radius);
 
-    fragColor = vec4(in_color.rgb, in_color.a * alpha);
+    float alpha_out = smoothstep(0.0, smoothness, distance);
+    float alpha_in = 1.0 - smoothstep(thickness, thickness+smoothness, distance);
+
+    fragColor = vec4(in_color.rgb, in_color.a * alpha_out * alpha_in);
 }
\ No newline at end of file
diff --git a/resources/shaders/source/rect.vert.glsl b/resources/shaders/source/rect.vert.glsl
index 00785db..3eb6bd4 100644
--- a/resources/shaders/source/rect.vert.glsl
+++ b/resources/shaders/source/rect.vert.glsl
@@ -12,6 +12,7 @@ layout(location = 3) in uvec4 color;
 layout(location = 0) out vec4 out_color;
 layout(location = 1) out vec4 out_quad_size;
 layout(location = 2) out float out_radius;
+layout(location = 3) out float out_thickness;
 
 void main()
 {
@@ -26,4 +27,5 @@ void main()
 	out_color = vec4(color) / 255.0;
 	out_quad_size = vec4(attr);
 	out_radius = float(abs(uv.x));
+	out_thickness = float(uv.y - uv.x);
 }
diff --git a/src/renderer.c3 b/src/renderer.c3
index eae3b8b..0b286c9 100644
--- a/src/renderer.c3
+++ b/src/renderer.c3
@@ -651,11 +651,11 @@ fn bool Renderer.push_sprite(&self, short x, short y, short w, short h, short u,
 	return self.map_quad(qa);
 }
 
-fn bool Renderer.push_quad(&self, short x, short y, short w, short h, uint color, ushort radius = 0)
+fn bool Renderer.push_quad(&self, short x, short y, short w, short h, uint color, ushort radius = 0, ushort thickness = 0)
 {
 	QuadAttributes qa = {
 		.pos = {.x = x, .y = y, .w = w, .h = h},
-		.uv  = {.u = radius, .v = radius},
+		.uv  = {.u = radius, .v = radius+thickness},
 		.color = color
 	};
 
@@ -866,7 +866,7 @@ fn void Renderer.render_ugui(&self, CmdQueue* queue)
 	foreach (&c : queue) {
 		if (c.type == CMD_RECT) {
 			CmdRect r = c.rect;
-			self.push_quad(r.rect.x, r.rect.y, r.rect.w, r.rect.h, r.color.to_uint(), r.radius);
+			self.push_quad(r.rect.x, r.rect.y, r.rect.w, r.rect.h, r.color.to_uint(), r.radius, r.thickness);
 		} else if (c.type == CMD_SPRITE) {
 			CmdSprite s = c.sprite;
 			self.push_sprite(s.rect.x, s.rect.y, s.texture_rect.w, s.texture_rect.h, s.texture_rect.x, s.texture_rect.y, s.hue.to_uint());