Make the modified property names bold through uss

com.unity.shadergraph/Editor/Drawing/Blackboard/BlackboardFieldPropertyView.cs

             m_Property = property;
 
             m_ReferenceNameField = new TextField(512, false, false, ' ');
+            m_ReferenceNameField.AddStyleSheetPath("Styles/PropertyNameReferenceField");
             AddRow("Reference", m_ReferenceNameField);
             m_ReferenceNameField.value = property.referenceName;
             m_ReferenceNameField.isDelayed = true;
                 m_ReferenceNameField.value = property.referenceName;
 
                 if (string.IsNullOrEmpty(property.overrideReferenceName))
-                    m_ReferenceNameField.style.fontStyle = StyleValue<FontStyle>.Create(FontStyle.Normal);
+                    m_ReferenceNameField.RemoveFromClassList("modified");
-                    m_ReferenceNameField.style.fontStyle = StyleValue<FontStyle>.Create(FontStyle.Bold);
+                    m_ReferenceNameField.AddToClassList("modified");
 
                 DirtyNodes(ModificationScope.Graph);
                 UpdateReferenceNameResetMenu();
-                m_ReferenceNameField.style.fontStyle = StyleValue<FontStyle>.Create(FontStyle.Bold);
+                m_ReferenceNameField.AddToClassList("modified");
 
             if (property is Vector1ShaderProperty)
             {
             {
                 m_Property.overrideReferenceName = null;
                 m_ReferenceNameField.value = m_Property.referenceName;
-                m_ReferenceNameField.style.fontStyle = StyleValue<FontStyle>.Create(FontStyle.Normal);
+                m_ReferenceNameField.RemoveFromClassList("modified");
                 DirtyNodes(ModificationScope.Graph);
             }, ContextualMenu.MenuAction.AlwaysEnabled);
         }

com.unity.shadergraph/Editor/Resources/Styles/PropertyNameReferenceField.uss

+TextField.modified {
+    font-style: bold;
+}

com.unity.shadergraph/Editor/Resources/Styles/PropertyNameReferenceField.uss.meta

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