Limit Text width in Featured Slider

Hi, how can I make shure that the text shown in the featured slider is not wider than the image? See: http://sf-plochingen.schachvereine.de/sfp2/ One slide is ok, but this text should not be displayed left and right to the image: "18. Plochinger ..... 2017" I hope you understand what I mean :-) In the preview, shown in the customizer, it looks fine, but not in live view. Regards Bernhard