/* 更新提示独立于 Flutter 画布，仅在正式 Web 版本发现更新时显示。 */
.pwa-update {
  position: fixed;
  z-index: 2147483647;
  bottom: max(16px, env(safe-area-inset-bottom));
  left: 50%;
  transform: translateX(-50%);
  width: min(560px, calc(100% - 32px));
  box-sizing: border-box;
  padding: 16px;
  border: 1px solid #d8dcd2;
  border-radius: 20px;
  background: #fafbf6;
  color: #20241b;
  box-shadow: 0 6px 24px #0003;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: flex-end;
  font: 14px/1.6 system-ui, sans-serif;
}
.pwa-update span { flex: 1 0 100%; }
.pwa-update button {
  font: inherit;
  min-height: 44px;
  padding: 8px 16px;
  border: 0;
  border-radius: 24px;
  background: #e9ece3;
  color: #20241b;
  cursor: pointer;
}
.pwa-update button:focus-visible { outline: 2px solid #658000; outline-offset: 3px; }
.pwa-update .pwa-update-primary { background: #ccff33; color: #182000; }
.pwa-update button:disabled { opacity: .6; cursor: wait; }
@media (prefers-color-scheme: dark) {
  .pwa-update { background: #191d1b; color: #f2f5ec; border-color: #394035; }
  .pwa-update button:not(.pwa-update-primary) { background: #30382c; color: #f2f5ec; }
}