The linked site lists a wealth of CSS hacks that let you apply styles to just that one browser. You should be using this mostly for fixing browser issues and not give up on creating solid styles.

Rails Long Term Support

Rails LTS provides security patches for old versions of Ruby on Rails (2.3, 3.2, 4.2 and 5.2)

Prevents you from data breaches and liability risks
Upgrade at your own pace
Works with modern Rubies

Browser Hacks: CSS Rules to Target Specific Browsers And Versions

Rails Long Term Support