body {
  font-family: Arial;
  background: #0f172a;
  color: white;
  display: flex;
  justify-content: center;
  margin-top: 100px;
}

.app {
  text-align: center;
}

input {
  padding: 10px;
  margin: 10px;
}

button {
  padding: 10px;
  background: green;
  color: white;
  border: none;
  cursor: pointer;
}