Stocks closed slightly lower Thursday ahead of the three-day weekend and a critical vote on Greek debt. The Nasdaq fell 0.1% and the S&P 500 lost a smidgen, while the Dow Jones industrial average faded for a nearly 0.2% loss. Volume was lighter than Wednesday’s pace, according to preliminary data in the stock market today. For the week, the Nasdaq fell 1.4%. The S&P 500 and the Dow dropped 1.2%.