Userstyle for hiding everything on Facebook except chat

style.css

body {
    background-image: url(https://lh3.googleusercontent.com/vNRD8biNwF9fJN7VZBxi97h47noTxeE3jpKA308NrudcTtlHakyBDyLpA1EQJit9tX0JDEogxCRUMfg=w2048-h1536-rw-no);
    background-size: cover;
    overflow: hidden;
}

/* Things I want hidden */
#pagelet_bluebar {
    visibility: hidden;
}
#globalContainer {
    visibility: hidden;
}
/* TODO: Facebook-post-as-chat thingy */

/* I'm not sure if these identifiers ever change */
#u_0_1q {  /* notification popups */
    visibility: hidden;
}

/* Things that I do want visible. Of course, empty CSS rules do nothing, but it's nice to have these IDs written down */
#pagelet_dock {}  /* visible */