Welcome to our forum,
you can display team member in a row by two different ways,
By px value and % value,
#1, if you want to display exact 3 item in a row try less than 33% no matter what screen size is , you also have option Tablet , Mobile
you may need adjust value to get 3 item in a row. its also depend on margin you set for items
And another one is px value if you fixed the width value like 300px no matter what screen size is , you can also set different value for Tablet , Mobile device.
Please try and let me know if you can do it, otherwise you can send me admin access so i can fix the issue.