Change background on sections/sub-pages

/*Change BG on sections/sub-pages*/
.agenda,
.appointments,
.people,
.discussions,
.game,
.embed,
.chat,
.chat_inbox,
.chat_people,
.companies,
.maps,
.search,
.surveys,
.documents,
.alerts,
.infobooth,
.activity_feed,
.chat_inbox,
.legal,
.user,
.about
{
background: url("URL HERE");
background-position: center center;
background-repeat: no-repeat;
background-size: cover;
background-attachment:fixed;
padding-top:10px;
min-height:calc(100vh - 50px);
}