@keyframes blink {
    50% { opacity: 0.0; }
}

@keyframes pulse {
    from { opacity: 0.0; }
    50%  { opacity: 0.5; }
    to   { opacity: 1;   }
}

.blink-effect {
    animation: blink var(--effect-time, 0.5s) step-start 0s infinite;
}

.pulse-effect {
    animation: pulse var(--effect-time, 0.75s) linear 0s infinite;
    animation-direction: alternate;
}