I like using the web resources, rather than read IRS code (although Cornell's presentation is nice). I also wanted to find a resource that includes recent changes such as CAA:

https://www.cohencpa.com/insights/articles/consolidated-appropriations-act-allows-100-percent

https://www.irs.gov/newsroom/tax-cuts-and-jobs-act-a-comparison-for-businesses

https://www.irs.gov/pub/irs-drop/td-9925.pdf

https://www.irs.gov/pub/irs-drop/n-21-25.pdf

"The 2017 TCJA generally eliminated the deduction for any expenses related to activities generally considered entertainment, amusement or recreation. However, taxpayers may still deduct business expenses related to food and beverages if certain requirements are met.

These final regulations address the disallowance of the deduction for expenditures related to entertainment, amusement or recreation activities, including the applicability of certain exceptions to this disallowance. They also provide guidance to determine whether an activity is considered entertainment. The final regulations also address the limitation on the deduction of food and beverage expenses."