removed unneeded css

public/assets/css/main.less

@@ -328,20 +328,6 @@ button, .button {
         opacity: 0.4;
         cursor: not-allowed;
     }
-
-    &.button-label {
-        background: transparent;
-
-        &:hover {
-            background: rgba(255, 255, 255, 0.2);
-            color: #fff;
-        }
-        &:active {
-            background: #fff;
-            color: #222;
-            cursor: pointer;
-        }
-    }
 }
 input[type='range'] {
     overflow: hidden;