How to make blinking/flashing text with CSS 3

You are first to set opacity: 1; and then you are ending it on 0, so it starts from 0% and ends on 100%, so instead just set opacity to 0 at 50% and the rest will take care of itself.The best way to get a pure “100% on, 100% off” blink, like the old <blink> is like this:

.blink_me {
  animation: blinker 1s linear infinite;
}

@keyframes blinker {
  50% {
    opacity: 0;
  }
}
<div class="blink_me">BLINK ME</div>