Need help with this moving a margin of an unordered list box

AS you can see in the attached photo, this Unordered list box I created is too far to the right. I used developer tools to discover where I needed to edit, yet when I tried to put the code into quick css it didn’t work. I used this code as I only want to affect this UL element on this post. Nothing happened.

.post-id-1819 ul ul {
    margin: 4px 0 5px -25px !important;
}

I’m positive this is the right post ID, and editing the margin in dev tools to this value worked so why is it not working here? What did I do wrong?