body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f5f7fa;
}

.container {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

.card {
  background: #fff;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
  width: 100%;
  max-width: 500px;
}

h1 {
  margin-top: 0;
}

.tariff-option {
  border: 1px solid #ddd;
  border-radius: 8px;
  padding: 10px;
  margin: 10px 0;
}

button {
  width: 100%;
  padding: 12px;
  background: #007bff;
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 16px;
  cursor: pointer;
}

button:disabled {
  background: #aaa;
}

.error {
  color: red;
}

.loader {
  text-align: center;
}

/* Modal */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.5);
  display: flex;
  justify-content: center;
}

.modal.hidden {
  display: none;
}

.modal-content {
  background: white;
  padding: 20px;
  border-radius: 10px;
  max-width: 400px;
  text-align: center;
}