/* 向上的箭头 */ .dot-top { font-size: 0; line-height: 0; border- 10px; border-color: red; border-top- 0; border-style: dashed; border-bottom-style: solid; border-left-color: transparent; border-right-color: transparent; } /* 向右的箭头 */ .dot-right { font-size: 0; line-height: 0; border- 10px; border-color: red; border-right- 0; border-style: dashed; border-left-style: solid; border-top-color: transparent; border-bottom-color: transparent; } /* 向下的箭头 */ .dot-bottom { font-size: 0; line-height: 0; border- 10px; border-color: red; border-bottom- 0; border-style: dashed; border-top-style: solid; border-left-color: transparent; border-right-color: transparent; } /* 向左的箭头 */ .dot-left { font-size: 0; line-height: 0; border- 10px; border-color: red; border-left- 0; border-style: dashed; border-right-style: solid; border-top-color: transparent; border-bottom-color: transparent; }