“Demolition Man,” the opening track on Euphoria, Def Leppard’s seventh studio album, plays like a typical installment of VH1’s rock-bio series Behind the Music: “Let me loose, I just got back/I was pushed and I got dragged/I tasted mud, I tasted wine/Kissed the life I left behind.” The moral of the tale: Every multimillion-selling hack gets a second chance. These blue-collar Brits have always been motivated by sales rather than art, so it’s little wonder that they’ve abandoned the more introspective tone struck on Slang (1996), a commercial flop, to return to their Eighties metal-for-the-malls formula: hooks big enough to beach Moby Dick, lean arrangements that owe more to Thin Lizzy than to Black Sabbath and germ-free production that emphasizes high-end sheen over low-end sludge. Old crony Mutt Lange takes time out from shepherding the career of his wife, Shania Twain, to lend a heavy hand on a couple of would-be hits, including “Promises,” which resurrects the “Pour Some Sugar on Me” buzz. Yet the defining characteristic of Euphoria is its bloodlessness, from the robotic drum tracks to the disconcertingly inhuman tone of those trademark massed vocal choruses. Behind the Music notwithstanding, the flesh-and-blood Def Leppard apparently never made it out of the Eighties alive.