I still generally avoid browser-specific hacks like these, aiming for lowest-common-denominator most-minimal HTML that still satisfies most browsers. However, now and then there's just no avoiding it.

I am continuously in awe of the Web's decentralized and open nature that allows something like this to happen-- for one reasonably complex file/application to be compatible with 30 years of co-evolving client software written by many different developers and teams, much of it no longer supported.