body {
  font-family: system-ui, sans-serif;
  max-width: 480px;
  margin: 2rem auto;
  padding: 0 1rem;
}

h1 {
  margin-bottom: 1.5rem;
}

form {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin: 1rem 0;
}

label {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.9rem;
}

input {
  padding: 0.5rem;
  font-size: 1rem;
}

button {
  padding: 0.5rem 1rem;
  font-size: 1rem;
  cursor: pointer;
  align-self: flex-start;
}

.balance {
  font-size: 1.5rem;
}

.message {
  min-height: 1.2rem;
}

.message.error {
  color: #b00020;
}

.message.success {
  color: #1b7a1b;
}