diff --git a/d3fendtools/as_mermaid/__init__.py b/d3fendtools/as_mermaid/__init__.py
index 5e0bca8..53218d4 100644
--- a/d3fendtools/as_mermaid/__init__.py
+++ b/d3fendtools/as_mermaid/__init__.py
@@ -139,6 +139,7 @@ class RDF2Mermaid:
         K8S.Namespace,
         K8S.Registry,
         K8S.Application,
+        K8S.Service,
         # DC are groups.
         K8S.DeploymentConfig,
         K8S.Deployment,
@@ -333,11 +334,11 @@ def render(self):
         return ret
 
     @staticmethod
-    def create_tree(tree):
+    def create_tree(tree: dict):
         """Create a tree of subgraphs according to mermaid syntax."""
         rendered = set()
 
-        def _render_tree(parent, data):
+        def _render_tree(parent, data, is_namespace=False):
             label = data.get("label") or ""
             parent_type = data.get("type")
             children = data.get("children") or []
@@ -352,7 +353,7 @@ def _render_tree(parent, data):
                     continue
                 if child == parent:
                     continue
-                if parent_type == K8S.Namespace:
+                if (is_namespace, parent_type) == (False, K8S.Namespace):
                     # Namespace should be processed last.
                     # Deployment* and Service* should be processed
                     #   under Application.
@@ -402,5 +403,7 @@ def _render_tree(parent, data):
                 tree_namespace.append((parent, data))
                 continue
             yield from _render_tree(parent, data)
+
+        # Render namespaces last.
         for parent, data in tree_namespace:
-            yield from _render_tree(parent, data)
+            yield from _render_tree(parent, data, is_namespace=True)
diff --git a/d3fendtools/as_mermaid/__main__.py b/d3fendtools/as_mermaid/__main__.py
index b923ae7..e35bb90 100644
--- a/d3fendtools/as_mermaid/__main__.py
+++ b/d3fendtools/as_mermaid/__main__.py
@@ -12,7 +12,7 @@
 
 
 @click.command()
-@click.argument("files", nargs=-1, type=click.Path(exists=True))
+@click.argument("files", nargs=-1, type=click.Path(exists=True), required=True)
 @click.option("--output", "-o", help="Output markdown file")
 def main(files, output):
     output_md = Path(output)
diff --git a/d3fendtools/kuberdf/base.py b/d3fendtools/kuberdf/base.py
index f1283bb..51359d0 100644
--- a/d3fendtools/kuberdf/base.py
+++ b/d3fendtools/kuberdf/base.py
@@ -224,6 +224,9 @@ def __init__(self, manifest: dict | None = None, ns: str = None) -> None:
         self.kind = manifest["kind"]
         self.metadata = manifest["metadata"]
         self.name = self.metadata["name"]
+        from urllib.parse import quote
+
+        self.name = quote(self.name, safe="")
         self.namespace = manifest["metadata"].get("namespace", ns or "default")
         self.ns = URIRef(f"https://k8s.local/{self.namespace}")
         self.spec = manifest.get("spec", {})