body {
  background-color: #f6f8fa;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
}

.checkout-container {
  width: 100%;
  max-width: 420px;
}

.checkout-panel {
  background-color: #fff;
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.1);
  overflow: hidden;
}

.panel-header {
  padding: 20px 24px;
  background-color: #f6f8fa;
  border-bottom: 1px solid #e5e7eb;
}

.logo-link {
  display: flex;
  align-items: center;
  text-decoration: none;
  color: #111827;
  font-weight: 600;
  font-size: 18px;
}

.logo-link img {
  margin-right: 10px;
}

.panel-body {
  padding: 24px;
}

.panel-body h2 {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 16px 0;
  color: #4b5563;
}

.order-item, .order-total {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 16px;
  padding: 12px 0;
}

.order-item {
  color: #374151;
}

.order-total {
  font-weight: 600;
  color: #111827;
  border-top: 1px solid #e5e7eb;
  margin-top: 8px;
}

#payment-form {
  margin-top: 24px;
}

.pay-button {
  width: 100%;
  padding: 12px;
  background-color: #2563eb;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.2s ease;
  margin-top: 16px;
}

.pay-button:hover {
  background-color: #1d4ed8;
}

#error-message {
  color: #dc2626;
  font-size: 14px;
  margin-top: 12px;
  text-align: center;
}