Refactor(app): simplify the app using the new function signatures

app.py

@@ -6,39 +6,39 @@
 
 import st_undp
 
-st_undp.set_page_config(
-    title="st-undp App",
-    menu_items={
-        "Get help": "https://github.com/undp-data/st-undp",
-        "Report a Bug": "https://github.com/undp-data/st-undp/issues",
-        "About": "Developed with [st-undp](https://github.com/undp-data/st-undp).",
-    },
-)
-
-st_undp.apply_style()
+st_undp.apply_style(title="st-undp App")
 
 # initialise states
 if st.session_state.get("title") is None:
     st.session_state["title"] = "Data Futures Exchange"
     st.session_state["subtitle"] = "st-undp Application"
     st.session_state["logo"] = "UNDP"
 
+
+# define the pages
+pages = [
+    st.Page(
+        page="pages/standard.py",
+        title="standard components",
+        url_path="./",  # use this pattern and not the `default` parameter
+    ),
+    st.Page(
+        page="pages/custom.py",
+        title="custom components",
+        url_path="/custom",
+    ),
+]
+
+
 # configure the header
 st_undp.header(
     title=st.session_state.title,
     subtitle=st.session_state.subtitle,
-    pages={
-        "standard components": "./",
-        "custom components": "./custom",
-    },
+    title_href="https://data.undp.org",
+    subtitle_href="./",
+    pages=pages,
     logo=st.session_state.logo.lower(),
 )
 
-pg = st.navigation(
-    pages=[
-        st.Page("pages/standard.py", url_path="/", default=True),
-        st.Page("pages/custom.py", url_path="/custom"),
-    ],
-    position="hidden",
-)
+pg = st.navigation(pages=pages, position="hidden")
 pg.run()