Custom Image background for Raw Content

Hi, the plugin is amazing. I am trying to customize it to make full width blocks with custom background on the page. It is too tricky with caption and image background. Is it possible to do similar with Raw Content. When I set up the background with just colour it works perfectly. It also works when I previously add a new custom class in css file and then just add the custom css name inside blox. What I try to accomplish is to do the same without previously adding new css class. But just copying the code inside of the blox doesn’t work ((

.bird-a1-1 {
	position: relative;
	text-align: center;
	background-color: #f5f5f5;
	border-bottom: solid 1px #dddddd;
	left: auto;
	opacity: 1;
	-moz-transition:    opacity .4s ease-in-out;
	-ms-transition:     opacity .4s ease-in-out;
	-o-transition:      opacity .4s ease-in-out;
	-webkit-transition: opacity .4s ease-in-out;
	transition:         opacity .4s ease-in-out;
	width: 100%;
	background: url("https://test1.elenakozliakova.com/wp-content/uploads/2016/01/CS_A1_S1_8-min.jpg") #f5f5f5;
	background-attachment: fixed;
	background-position: 50% 0px;
	background-repeat: no-repeat;
	-webkit-background-size: cover;
	-moz-background-size:    cover;
	background-size:         cover;
}

when I put bird-a1-1 as custom class it works when I just copy the code to put it after blox-id it doesn’t ((