ProtonMail Background Image

pm-image.css

html {
  /* Just change this image to your own */
  background: url(https://mail.protonmail.com/assets/img/login.jpg) no-repeat center center fixed #667cbd; 
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}
body, body #body, body header, body header a.logo, body section.sidebar, body #pm_main, #ptSidebar {
  background: transparent !important;
}
body #conversation-list-rows .conversation.read, .conversation.read {
  background: transparent;
}
.conversation.active {
  background: #828895 !important;
}
/* https://imgur.com/a/5fvzR */