.blink{
    animation-name: blinker;
    animation-duration: 5s;
    animation-iteration-count: infinite;
}
@keyframes blinker{
    0%{     border-color: #e7e7e7; color: #a7a7a7;    }
    50%{    border-color: #dc3545; color: white; }
    100%{   border-color: #e7e7e7; color: #a7a7a7;    }
}