How can I make the cards around the image an animated gradient colour?

Hi copied and saved the list section from my portfolio, which is  a list with clickable images ( https://www.brainforestcreative.com/portfolio)

I now want to add code in order to make the cards an animated gradient version of the colours of my site. I have this already but it does not seem to be working, as I have had to make some edits when copying the section from my portfolio page

.user-items-list-item-container[data-section-id="643b0332cf62e66cb03c9ca9"] li.list-item {
    background: linear-gradient(-45deg,#53d6ff,#666be1,#e45372,#f07c63);
    background-size: 400% !important;
    -webkit-animation: Gradient 10s ease infinite !important;
    -moz-animation: Gradient 10s ease infinite !important;
    animation: Gradient 10s ease infinite !important;
}

See image for the colour scheme they should be (animated)

Any advice, do I need to add more code?

Thanks

Alex

This is code for all 4 lists

body#collection-643afedc7572ef34f045bbf2 .user-items-list-item-container li {
    background: linear-gradient(-45deg,#53d6ff,#666be1,#e45372,#f07c63);
    background-size: 400% !important;
    -webkit-animation: Gradient 10s ease infinite !important;
    -moz-animation: Gradient 10s ease infinite !important;
    animation: Gradient 10s ease infinite !important;
    padding-top: 20px;
}