diff --git a/src/pages/2-model_creation.py b/src/pages/2-model_creation.py
index c2265ad93e654e213ac3af790d5bc86caaee3b9e..f89dd4e98f7cc7b75cfdfe567c9ef4c18d57d2fe 100644
--- a/src/pages/2-model_creation.py
+++ b/src/pages/2-model_creation.py
@@ -4,6 +4,7 @@ from Modules import *
 from Class_Mod.DATA_HANDLING import *
 add_header()
 add_sidebar(pages_folder)
+local_css(css_file / "style_model.css")
 
 
 @st.cache_data
@@ -17,7 +18,6 @@ def delete():
             elif os.path.isdir(chemin_fichier):
                 os.rmdir(chemin_fichier)
 delete()
-local_css(css_file / "style_model.css")
 
 # Initialize the variable in session state if it doesn't exist for st.cache_data
 if 'counter' not in st.session_state:
diff --git a/src/style/header.py b/src/style/header.py
index 30719da2c2df503a922ec3d7102c666c21922230..fe93bca72a0bacbb7e66306844e7a920b1e5de78 100644
--- a/src/style/header.py
+++ b/src/style/header.py
@@ -14,6 +14,8 @@ def add_header():
 def add_sidebar(pages_folder):
     if 'interface' not in st.session_state:
         st.session_state['interface'] = 'simple'
+    else:
+        st.session_state["interface"] = st.session_state.get('interface')
 
     # # TOC menu on the left
     show_pages(