.blink {
    animation-name:blinking_red;
    animation-duration:3s;
}

@keyframes blinking_red {
    0% {
        border-style:solid;
        border-color:#ced4da;
    }

    7.5% {
        border-color:red;
    }

    15% {
        border-color:transparent;
    }

    22.5% {
        border-color:red;
    }

    30% {
        border-color:transparent;
    }

    37.5% {
        border-color:red;
    }

    100% {
        border-color:#ced4da;
    }
}

.blink_crimson {
    animation-name:blinking_crimson;
    animation-duration:3s;
}

@keyframes blinking_crimson {
    0% {
        border-style:solid;
        border-color:#ced4da;
    }

    7.5% {
        border-color:crimson;
    }

    15% {
        border-color:transparent;
    }

    22.5% {
        border-color:crimson;
    }

    30% {
        border-color:transparent;
    }

    37.5% {
        border-color:crimson;
    }

    100% {
        border-color:#ced4da;
    }
}