Multiline closed dataset header (#20)

- Split the closed dataset headers into 2 lines (640f29f51ac965b1806eae61f780328669d57913)

app/backend/data_page.py

@@ -225,7 +225,7 @@ def table_area(group_name, grid_state, data_engine=None, df=None):
         ".custom-header-style": {
             "text-overflow": "clip",
             "overflow": "visible",
-            "white-space": "normal",
+            "white-space": "pre-line",
             "height": "auto",
             "font-family": 'Arial',
             "font-size": "14px",

app/backend/multi_header_util.py

@@ -26,6 +26,24 @@ def get_dataset_url_name(field_name):
     return field_name
 
 
+def format_closed_dataset_header(column_name):
+    """
+    Format closed dataset header to display in two lines
+    :param column_name: Original column name like "ClosedDataset 2 (German Legal Sentences)"
+    :return: Formatted header with line break
+    """
+    if column_name.startswith("ClosedDataset ") and "(" in column_name:
+        # Split "ClosedDataset N (description)" into "ClosedDataset N" and "(description)"
+        parts = column_name.split("(", 1)
+        if len(parts) == 2:
+            dataset_part = parts[0].strip()  # "ClosedDataset N"
+            description_part = "(" + parts[1]  # "(description)"
+            return f"{dataset_part}\n{description_part}"
+    
+    # Return original if it doesn't match the pattern
+    return column_name.replace('_', '')
+
+
 def mutil_header_options(column_list: list, avg_column: str, is_section: bool):
     """
     get mutil_header_options - 优化版本，减少组件实例化
@@ -62,7 +80,7 @@ def mutil_header_options(column_list: list, avg_column: str, is_section: bool):
         'cellClass': 'custom-cell-style',
         'autoHeaderHeight': True,
         'children': [
-            {'headerName': column.replace('_', ''),
+            {'headerName': format_closed_dataset_header(column),
              'field': column,
 
              "headerComponentParams": {