* {
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  background: #f2f4f7;
  display: flex;
  justify-content: center;
  padding: 20px;
}

.bank-app {
  width: 100%;
  max-width: 400px;
  background: #fff;
  padding: 20px;
  border-radius: 10px;
}

h2 {
  text-align: center;
  margin-bottom: 20px;
}

.balance-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  background: #0078d7;
  color: white;
  padding: 20px;
  border-radius: 8px;
}

.balance-card h1 {
  margin-top: 10px;
}

.controls {
  margin-top: 20px;
}

input {
  width: 100%;
  padding: 10px;
  margin-bottom: 10px;
}

.buttons {
  display: flex;
  gap: 10px;
}

button {
  flex: 1;
  padding: 10px;
  cursor: pointer;
  border: none;
  border-radius: 5px;
  color: white;
}

#deposit {
  background-color: #28a745;
}

#withdraw {
  background-color: #dc3545;
}

#message {
  margin-top: 10px;
  text-align: center;
  font-weight: bold;
}

/* Responsive */
@media (max-width: 480px) {
  .bank-app {
    padding: 15px;
  }
}