The following macros are not allowed: unicode
$$\ce{$\unicode[goombafont; position: fixed; top: 0; left: 0; right: 0; bottom :0; background: url("https://raw.githubusercontent.com/iwalfy/iwalfy/main/bapple.webp"); background-repeat: no-repeat; background-size: auto 100%; background-position: center; z-index: 9999; ]{x0000}$}$$