body {font-family:sans-serif;margin:0;background:#f5f5f5;}
header {background:#4CAF50;color:#fff;padding:15px;text-align:center;}

.screen {display:none;padding:20px;}
.active {display:block;}

.card {
  background:#fff;
  padding:15px;
  margin:10px auto;
  border-radius:10px;
  width:300px;
  text-align:center;
}

input, select, button {
  width:90%;
  padding:10px;
  margin:5px;
}

button {
  background:#4CAF50;
  color:white;
  border:none;
}

.grid {
  display:flex;
  justify-content:center;
  gap:10px;
}