Joomla 4 is based on Bootstrap 5.x+ framework by default. NorrCompetition comes with a default theme based on Uikit framework which loads independently and has no conflict with Bootstrap (btw, if you're using a Joomla template based on the same framrwork, you can disable loading Uikit libraries in component settings). If your template is based on another front-end framework, make sure it is compatible or has no conflict with a default Joomla template Cassiopeia. By the way, NorrCompetition supports Joomla template overrride system, so you can customize the component according to your needs at any time.