Jon Gruden Craps All Over SoFi Stadium Design For Weather Delay, Locker Rooms

Jon Gruden clearly ain't pleased with L.A.'s new $5.5 BILLION stadium ... bashing the state-of-the-art facility for its not-so weather-proof design and complicated visitors locker rooms after losing on Monday Night Football.

The Chargers vs. Raiders matchup was off to a delayed start due to a rare lightning storm in the City of Angels before kickoff ... with action paused 35 minutes before teams were able to take the field.

Gruden had a hard time wrapping his head around the delay -- considering SoFi Stadium is technically an indoor-outdoor building -- and says the whole fiasco had an impact on the game.

"I've never had an indoor stadium with a lightning delay," Gruden told reporters after the game.

"I’m not an engineer, I have no idea. I have never heard that. I thought it was a joke. But, it affected both teams."

Gruden wouldn't go as far as to say the delay led to the Raiders losing 28-14 to Justin Herbert and Co., adding, "It didn’t have anything to do with it."

But, Chucky's complaints didn't stop there -- Gruden also took issue with the set-up for the visiting team's locker room ... calling it "the most bizarre thing I've ever seen."

"I mean you can’t see anybody," he added. "It’s like a maze. So whoever contorted this visiting locker room, I’d like to meet this guy, see what his idea was."

FYI -- HKS, Inc. has worked on some of the most iconic stadiums in the NFL ... including the Dallas Cowboys' AT&T Stadium and Minnesota Vikings' U.S. Bank Stadium.

To compare, this is what the Chargers' locker room looks like.