body {
  background:#0e0e0e;
  color:#eaeaea;
  font-family: system-ui, sans-serif;
  display:flex;
  justify-content:center;
  align-items:center;
  height:100vh;
  margin:0;
}

.box {
  background:#161616;
  padding:30px;
  border-radius:12px;
  width:100%;
  max-width:420px;
  text-align:center;
}

input {
  width:100%;
  padding:12px;
  margin:15px 0;
  border:none;
  border-radius:8px;
  background:#222;
  color:#fff;
}

button {
  width:100%;
  padding:12px;
  background:#00ff99;
  border:none;
  border-radius:8px;
  font-weight:bold;
  cursor:pointer;
}
button:disabled {
  background:#444;
  color:#888;
  cursor:not-allowed;
}

button.active {
  background:#00ff99;
  color:#000;
  cursor:pointer;
}

.hint {
  margin-top:10px;
  font-size:13px;
  opacity:.6;
}