show disabled held piece

css/minimal.css

@@ -88,6 +88,10 @@ tr.matrix td:not(.mino) {
     animation-duration: 0.2s;
 }
 
+.disabled.mino {
+    filter: brightness(50%) contrast(50%);
+}
+
 @keyframes locked-animation {
     from {
         filter: saturate(50%) brightness(300%);