#app-error {
  display: none;
  position: fixed;
  z-index: 99999;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  background: #f5f5f5;
  color: #333;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  padding: 16px;
  overflow-y: auto;
}
#app-error.show {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
#app-error .err-card {
  background: #fff;
  border-radius: 8px;
  padding: 20px;
  max-width: 480px;
  width: calc(100% - 32px);
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
}
#app-error .err-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: #e53935;
  margin-bottom: 12px;
}
#app-error .err-msg {
  font-size: 1rem;
  word-break: break-all;
  margin-bottom: 12px;
}
#app-error .err-stack {
  font-size: 0.75rem;
  color: #999;
  background: #fafafa;
  padding: 12px;
  word-break: break-all;
  white-space: pre-wrap;
  max-height: 200px;
  overflow-y: auto;
}
#app-error .err-btn {
  display: inline-block;
  margin-top: 12px;
  padding: 8px 16px;
  background: #1976d2;
  color: #fff;
  border: none;
  border-radius: 4px;
  font-size: 1rem;
  cursor: pointer;
}