.flash-stack {
  position: fixed;
  top: 18px;
  right: 18px;
  z-index: 1200;
  display: grid;
  gap: 10px;
  max-width: min(420px, calc(100vw - 32px));
}

.flash-message {
  padding: 12px 14px;
  border-radius: 16px;
  border: 1px solid rgba(216, 227, 242, 0.9);
  background: rgba(255, 255, 255, 0.98);
  color: #182433;
  box-shadow: 0 18px 36px rgba(15, 31, 61, 0.12);
  line-height: 1.6;
}

.flash-message--success {
  border-color: rgba(21, 128, 61, 0.2);
  background: rgba(240, 253, 244, 0.98);
  color: #166534;
}

.flash-message--error {
  border-color: rgba(220, 38, 38, 0.18);
  background: rgba(254, 242, 242, 0.98);
  color: #b91c1c;
}