body {
  margin: 40px;
  background: #000;
  color: #fff;
  font: 14px/1.6 "Courier New", Courier, monospace;
}

a, pre { color: #0f0; }

p {
  width: 640px;
  font-size: 16px;
  line-height: 2.4;
}
p span { border: 1px solid #0f0; padding: 1px 3px; }

.scan { position: relative; margin: 40px 0; }
.scan img { display: block; width: 100%; }
.bb { position: absolute; border: 1px solid #0f0; }
.bb::after {
  content: attr(data-l);
  position: absolute;
  bottom: 100%;
  left: -1px;
  background: #0f0;
  color: #000;
  font-size: 10px;
  padding: 0 3px;
  white-space: nowrap;
}

.blink { animation: blink 1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }