CSS for single sites

Hey guys,

I want to change the CSS for a single site. I use the CSS plugin but I don’t know how to refer to one specific site.

that one already works:

.page-id-318 {
	background-image: url("http://www.plant-values.de/wp-content/uploads/2015/08/background-zukunftsstadt.jpg");
	background-position: center top;
	background-repeat: repeat-y;
	background-attachment: fixed;
	padding-bottom: 15px;

now I want to set the image-header to display:none and just don’t know how to adress it.

Begging for help!
Thanks to you


This will do it (if you’re using a header image for your secondary pages, not the slider):

.page-id-318 .header-image {
    display: none;

GREAT works fine! Thank you!