@media (max-width:767px) {
 body:not(.signed-in) #player { display:none; }
 /* Keep room for the invitation banner without reserving a hidden player. */
 body:not(.signed-in) #main {
  padding-bottom:calc(24px + var(--mobile-promo));
  scroll-padding-bottom:calc(24px + var(--mobile-promo));
 }
}