Hi Michael Lang,
Thanks for contacting Syncfusion support.
We suspect that CSS for pivot table component is not referred. So, kindly import the styles for pivot table in styles.css. Meanwhile, we have prepared a sample for your reference. Please check the below sample and UG for more information.
If still the problem exists, kindly reproduce the problem in the provided sample and revert us (or) send your sample that replicating the problem. This would be a very helpful for us to investigate the reported problem at our end and provide the solution at earliest.
Please let us know if you concern.
Regards,
Sivamathi.