Apple’s share of the U.S. computer hardware market slipped during the first quarter of 2014, with both IDC and Gartner seeing a year-over-year decline in worldwide PC shipments as consumers trend toward mobile. Unlike last quarter’s stellar performance, which saw Apple’s Mac buck the declining PC sales trend with a 30 percent year-to-year increase, the quarter ending in March proved to be more of a struggle for the company, according to market research firms IDC and Gartner.