Make Text on Slider Stand Out

I have a strange thing here!!
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I am trying to get the text captions in white to stand out more against the slider image. I have added the custom functions php code, and added the custom css class as “pbc-text” all is ok. However I can get any of the css to load it just shows the .pbc-text .slide-1 .avia-caption-content p {} with no content. I have tried this as a child and also in the quick css area and the same thing happens. Can you help please.