Go to the JsFiddle link, resize the browser and observe the font-size not changing
Duplicate of bug 87846
I am not able to reproduce this bug in Safari 15.6.1 and Safari Technology Preview 151 using attached JSFiddle and resizing the browser window do resize the font-size inside "red" box similar to all other browsers (Chrome Canary 106 and Firefox Nightly 105). I am going to mark this as "RESOLVED CONFIGURATION CHANGED". Please reopen, if you think this is not resolved. Thanks!