.test-mode-banner {
  position: sticky;
  z-index: 1000;
  top: 0;
  width: 100%;
  padding: 10px 16px;
  color: #ffffff;
  background: #b42318;
  border-bottom: 3px solid #7a140d;
  text-align: center;
  font-family: Arial, Helvetica, sans-serif;
  font-size: clamp(14px, 2vw, 18px);
  font-weight: 900;
  line-height: 1.25;
  letter-spacing: .06em;
  animation: test-warning-blink 1.4s ease-in-out infinite;
}

@keyframes test-warning-blink {
  0%, 100% { background: #b42318; }
  50% { background: #e14b3c; }
}

@media (prefers-reduced-motion: reduce) {
  .test-mode-banner { animation: none; }
}