Background for the vents page

This CSS rule defines that background of event page:

.layout-events body {
    background: url(/templates/ja_teline_v/images/ev-bg.jpg) no-repeat fixed center top #1a4093;
    background-size: 100%;
}

You can change with your own background image or set background to none if you don't want to show background.

.layout-events body {
    background: url(path/to/your/image.jpg) no-repeat fixed center top #1a4093 !important;
    background-size: 100%;
}

.layout-events body {
    background: none !important;
}