.mobile-filter-btn {
  display: none;
  background: #333;
  color: #fff;
  padding: 10px 16px;
  border: none;
  border-radius: 4px;
  font-size: 16px;
}
.mobile-filter-btn.active {
  background: #28a745;
  box-shadow: 0 0 10px rgba(40,167,69,0.5);
}
#filter-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  z-index: 999;
}
#filter-overlay.active { display: block; }
#mobile-filter-panel {
  position: fixed;
  top: 0; right: -100%;
  width: 85%; max-width: 360px;
  height: 100%; background: #fff;
  overflow-y: auto; z-index: 1000;
  transition: right .3s ease;
  padding: 20px;
}
#mobile-filter-panel.active { right: 0; }
#close-filter-panel {
  position: absolute; top: 10px; right: 10px;
  background: none; border: none; font-size: 24px;
}
@media (max-width:768px){
  .custom-filter-form { display:none; }
  .mobile-filter-btn { display:inline-block; margin-bottom:10px; }
}