Text disappearing after I leave edit mode

Site URL: https://www.nationalfashioncollege.com/partners

I'm using custom code to create a 6 column section of text on desktop and 2 column on mobile.

I am using this code currently in the custom css section:

@media screen and (min-width: 640px) {
#block-yui_3_17_2_1_1638761244808_11129 {
    column-count: 6;
    column-gap: 25px;
  }
}

@media screen and (max-width: 720px) {
#block-yui_3_17_2_1_1638761244808_11129 {
    column-count: 2;
    column-gap: 20px;
  }
}

When I am in edit mode the text shows up but as soon as I save it the text all vanishes. It is however showing on mobile. What am I doing wrong?!?!

I have tried clearing caches, different browsers, deleting section and trying again but same issue. Please help!

Edit your code to this (I changed some class name)

@media screen and (min-width: 768px) {
    #block-yui_3_17_2_1_1638761244808_11129>div {
        column-count:6;
        column-gap: 25px;
    }
}

@media screen and (max-width: 767px) {
    #block-yui_3_17_2_1_1638761244808_11129>div {
        column-count:2;
        column-gap: 20px;
    }
}

Unfortunately it's still doesn't seem to work. When I am in the Custom CSS screen it shows and as soon as I save it and refresh the page it disappears again.

Thank you! That worked a treat!