[FIX] Try fixing the position of the sidebar

assets/styles.css

@@ -53,16 +53,18 @@ input, textarea, select,
     background: var(--off-white) !important;
 }
 
-/* Default width — no !important so Streamlit's drag-to-resize JS can override it */
 section[data-testid="stSidebar"] {
     width: 350px;
 }
 
-/* Keep the sidebar fixed on screen while the main content scrolls */
-section[data-testid="stSidebar"] > div:first-child {
+div[data-testid="stSidebarContent"] {
     position: fixed;
-    overflow-y: auto;
+    top: 0;
+    left: 0;
     width: inherit;
+    height: 100vh;
+    overflow-y: auto;
+    z-index: 100;
 }
 
 /* ── 4. Markdown headings (st.markdown "### …") ────────────── */