body {
  margin: 25px;
  background-color: rgb(50, 147, 79);
  font-family: arial, sans-serif;
}

body::after {
  content: "Hacked!";
  white-space: pre;
  position: fixed;
  inset: 0;
  background: black;
  color: #00ff00;
  font-family: "Courier New", monospace;
  padding: 40px;
  font-size: 20px;
  animation: flicker 0.15s infinite alternate;
  z-index: 9999;
}

@keyframes flicker {
  from { opacity: 0.95; }
  to   { opacity: 1; }
}