Inserted pivot tables in spreadsheets now use the same table styling approach as other spreadsheet tables instead of a fixed pivot-specific look. This makes spreadsheet reports more visually consistent and easier to maintain without changing core business workflows.

This comit replace the hard-coded pivot style with table style when inserting a pivot.

Task: [3709540](https://www.odoo.com/web#id=3709540&cids=1&menu_id=4720&action=333&active_id=2328&model=project.task&view_type=form)