There are solutions that are 100% safe from all methods of copy on the computer or device (mobile). Yes, a person can still photograph the computer monitor but where is the line drawn?

For any solution to be effective, it needs to action at system level which is why JavaScript and CSS tricks are useless. Trying to apply copy protection to any of the popular web browsers is futile because not only do they have no access rights at system level, they are designed to do just the opposite.

The best solution imaginable is one that encrypts pages ready for delivery to a web browser that can decrypt those pages and prevent all copy while that page is on display.

Such a thing does exist.

Internet search is your best friend - seek and you will find options for every scenario.