.bell { display:inline-block; transform-origin: 50% 0%; }
.bell.bell-on { animation: ring 1.0s ease-in-out infinite; }
@keyframes ring {
  0% { transform: rotate(0); }
  10% { transform: rotate(12deg); }
  20% { transform: rotate(-12deg); }
  30% { transform: rotate(10deg); }
  40% { transform: rotate(-10deg); }
  50% { transform: rotate(6deg); }
  60% { transform: rotate(-6deg); }
  70% { transform: rotate(3deg); }
  80% { transform: rotate(-3deg); }
  100% { transform: rotate(0); }
}

/* Utilidades */
.small-muted { color:#6c757d; font-size:.875rem; }
.table td, .table th { vertical-align: middle; }