The default grid system provided in Bootstrap utilizes 12 columns that render out at widths of 724px, 940px (default without responsive CSS included), and 1170px. Below 767px viewports, the columns become fluid and stack vertically.
就是因为我在设定它的时候，我先想这样做它可能会传播，会打动人。经纬是不是帮了很多忙?是不是?不是也要说是。