Why does Safari 11.1.2 display in unformatted, plain text?

I am preparing a 2008 iMac (running El Capitan 10.11.6) for sale/donation. The hard drive has been wiped and the OS reinstalled and updated. The Safari version is 11.1.2.

When I use Safari to search the Apple Community support site, it always returns the results in unformatted, plain text, which is not easy to read/navigate. Any link is displayed as the old-fashioned blue underlined text. The same issue is evident when using Chrome 103.0.5060.134. Does anyone have a suggestion for what I can do to remedy this issue?