PREVIEW: https://i.imgur.com/o2oEZVx.png SUGGESTED USERCHROME CODES: /* Border around the active tab */ .tab-background[selected="true"] { border: 2px solid #497186 !important; border-radius: 5px !important; } /* Background for dark site favicon icon */ .tab-icon-image:not([selected="true"]) { background-color: slategray !important; border-radius: 15%; padding: 1px; transform: scale(1.20); }