TORONTO — Canada’s main stock index was down more than 300 points in late-morning trading in a broad-based decline, while U.S. stock markets also fell after a hotter-than-expected U.S. inflation report. The S&P/TSX composite index was down 324.17 points at 20,743.13. In New York, the Dow Jones industrial average was down 417.19 points at 38,380.19. […]