html, body {
  height: 100%;
  margin: 0;
  overflow: hidden;
}
body {
  background: black;
  color: #0f0;
  font-family: monospace;
  display: flex;
  flex-direction: column;
}
#out {
  white-space: pre-wrap;
  padding: 10px;
  flex: 1;
  overflow-y: auto;
}
#in {
  width: 100%;
  background: black;
  color: #0f0;
  border: none;
  outline: none;
  font-family: monospace;
  font-size: 16px;
  padding: 10px;
  box-sizing: border-box;
}
.glitch {
  animation: glitch 0.15s infinite;
}
@keyframes glitch {
  0% { opacity: 1; }
  50% { opacity: 0.7; }
  100% { opacity: 1; }
}