Custom CSS only working in edit mode

Site URL: https://www.expressdraftingllc.com/home/contact

On the contact page specifically, I have those two images on there in which I'd like the text and opacity to only show whilst hovering over them.

This is my current code line;

@media only screen and (min-width: 640px){
#block-yui_3_17_2_1_1728344822415_75558, #block-989e4203b20da71b4c0f,  {
    opacity: 0 !important;
    transition: opacity 0.5s;
  }
  #block-yui_3_17_2_1_1728344822415_75558:hover, #block-989e4203b20da71b4c0f:hover, {
    opacity: 1 !important;
  }
}

Any help is much appreciated!

Try remove comma 

The first thing I see is syntax errors.

You may find the W3C validator of use.

https://jigsaw.w3.org/css-validator/#validate_by_input