Update app.py

app.py

@@ -191,6 +191,25 @@ app.index_string = '''
                 --ag-foreground-color: var(--text-color);
                 --ag-row-border-color: var(--grid-border);
             }
+            .ag-theme-alpine .ag-pinned-left-header,
+            .ag-theme-alpine .ag-cell-last-left-pinned {
+                border-right: 2px solid var(--grid-border) !important;
+                margin-right: -1px !important;
+            }
+            
+            /* Mobile specific fixes */
+            .ag-theme-alpine.ag-grid-mobile .ag-pinned-left-header,
+            .ag-theme-alpine.ag-grid-mobile .ag-cell-last-left-pinned {
+                border-right: 2px solid var(--grid-border) !important;
+            }
+            
+            /* Ensure pinned columns maintain their position */
+            .ag-theme-alpine .ag-pinned-left-cols-container,
+            .ag-theme-alpine .ag-pinned-left-header {
+                position: sticky;
+                left: 0;
+                z-index: 1;
+            }
             .ag-floating-top {
                 border-bottom: 3px solid var(--border-color) !important;
             }
@@ -481,7 +500,7 @@ columnDefs = [
             "defaultOption": "greaterThanOrEqual"
         },
         "headerClass": "ag-left-aligned-header wrap-text",
-        "cellClass": "ag-left-aligned-cell",
+        "cellClass": ["ag-left-aligned-cell", "border-left"],
         "wrapHeaderText": True,
         "autoHeaderHeight": True,
         "suppressSizeToFit": True,