style tweak

bin/style.css

@@ -725,7 +725,7 @@ input[type=checkbox]:checked:after {
 }
 .hide-properties .group > .title {
   text-align: center;
-  background-color: #1e1e1e;
+  background-color: #151515;
   cursor: pointer;
   user-select: none;
   padding: 1px;

bin/style.less

@@ -810,7 +810,7 @@ input[type=checkbox] {
 	.group {
 		>.title {
 			text-align : center;
-			background-color : rgb(30,30,30);
+			background-color : #151515;
 			cursor:pointer;
 			user-select:none;
 			padding : 1px;