Battery cable came off!
 

Hi, was checking my '95 Civic 1.6L today. It was idling, and I heard
the idle sound change: it seemed higher. I stepped on the gas a bit,
and I heard a soft electrical "pop" near the stereo panel. I hurriedly
shut down the engine, I found that the negative battery cable had come
off! (It had a quick-release connection). I connected it, restarted and
found everything working fine, even checked all the stereo functions,
LEDs, and the ECU.

I've read that the battery acts as a big capacitor to smooth out
voltage spikes. The entire episode didn't take more that 10 seconds,
but I'm worried... could there be any permanent damage?