After 2010’s Before Today saw Ariel Pink emerge from his lo-fi netherworld to become America’s preeminent avant-pop star, Mature Themes furthers his acclimatization to the spotlight. The album boasts some of his most openhearted tunes: The title track crosswires a tender ‘70s serenade with Kraftwerkian synths; “Only in My Dreams” is a sun-dappled gem spit-shined by Byrdsy jangle. But Pink’s increasingly sophisticated songcraft is countered by moments of anarchy: “Schnitzel Boogie” is, indeed, a brown-note polka about craving the titular delicacy.