youtube-chat.css

/* hide top bar text */
/* yt-live-chat-header-renderer { display: none; } yt-live-chat-ticker-renderer { padding-top: 12px; } */
/* hide send message bit */
#panel-pages { display: none;}
/* hide top menu triangel */
yt-icon#label-icon {  display: none;}
/* Hide topbar three dots */
yt-icon-button#overflow {display: none;}
/* hide youtube viewer message */
yt-live-chat-viewer-engagement-message-renderer { display: none; }

/* https://obsproject.com/forum/resources/youtube-live-chat-css-presets.1182/ */
/* Hide scrollbar */
yt-live-chat-item-list-renderer[allow-scroll] #item-scroller.yt-live-chat-item-list-renderer {
    overflow: hidden;
}
/* Make the background transparent */
.style-scope yt-live-chat-renderer,yt-live-chat-header-renderer { background-color: rgba(255, 255, 255, 0); }
#items.yt-live-chat-item-list-renderer > *.yt-live-chat-item-list-renderer { background-color: rgba(255, 255, 255, 0); }

/* Make the background white */
/*
.style-scope yt-live-chat-renderer,yt-live-chat-header-renderer { background-color: rgba(255, 255, 255, 0); }
#items.yt-live-chat-item-list-renderer > *.yt-live-chat-item-list-renderer { background-color: rgba(255, 255, 255, 0); }
*/
/* Change url from www. to gaming. for dark background AND remove/comment lines 17 through 25*/