Make PortInputView use pre-multiplied alpha background color and put its edge behind itself and node (still need to make it render behind other nodes)

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/MaterialNodeView.cs

                     inputContainer.Add(port);
                     var portInputView = new PortInputView(slot);
                     Add(portInputView);
+                    mainContainer.BringToFront();
                     m_Attachers.Add(new Attacher(portInputView, port, SpriteAlignment.LeftCenter) { distance = -8f });
                 }
             }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/PortInputView.cs

             m_SlotType = slot.concreteValueType;
             AddToClassList("type" + m_SlotType);
 
+            m_EdgeControl = new EdgeControl
+            {
+                @from = new Vector2(212f - 21f, 11.5f),
+                to = new Vector2(212f, 11.5f),
+                edgeWidth = 2,
+                pickingMode = PickingMode.Ignore
+            };
+            Add(m_EdgeControl);
+
             m_Container = new VisualElement { name = "container" };
             {
                 m_Control = m_Slot.InstantiateControl();
                 m_Container.Add(slotElement);
             }
             Add(m_Container);
-
-            m_EdgeControl = new EdgeControl
-            {
-                @from = new Vector2(212f - 21f, 11.5f),
-                to = new Vector2(212f, 11.5f),
-                edgeWidth = 2,
-                pickingMode = PickingMode.Ignore
-            };
-            Add(m_EdgeControl);
 
             m_Container.visible = m_EdgeControl.visible = m_Control != null;
             m_Container.clippingOptions = ClippingOptions.ClipAndCacheContents;

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Resources/Styles/MaterialGraph.uss

 }
 
 PortInputView > #container {
-    background-color: #393939;
+    background-color: rgba(63, 63, 63, 0.8);
     flex-direction: row;
     align-items: center;
     padding-left: 8;