@cookieValue

    @cookieValue("mode").assign("mode")
    
    @if("dark".equalsIgnoreCase(mode.toString())){
        
        <link rel=stylesheet type="text/css" href='@url("/css/dark.css")' />
        
    }else{
        
        <link rel=stylesheet type="text/css" href='@url("/css/light.css")' />
        
    }
    Result: <link rel=stylesheet type="text/css" href='/css/light.css' />