[Ultimate Branding] Special character must be escaped

Trying to add css to ultimate branding getting error that special characters must be escaped. What is the proper way to escape special characters.

#adminmenu li.menu-top:hover, #adminmenu li.opensub > a.menu-top, #adminmenu li > a.menu-top:focus {

position: relative;

background-color: #191e23;

color: #00b9eb;

background-image: linear-gradient(225deg,#f92c8b 0%,#b02cd6 100%)!important;

}