add "transform" vendor prefixes

Author: AntouanK

docs/dist/less/components/checkbox.less

@@ -37,13 +37,13 @@
 	input {
 		display: @checkbox-input-display;
 	}
-	
-	.mui-checkbox-label { 
+
+	.mui-checkbox-label {
 		position: relative;
 		left: @checkbox-label-spacing;
 		padding: 0 5px;
-	} 
-	
+	}
+
 	.mui-checkbox-box {
 		.ease-out;
 		background-color: @checkbox-box-background-color;
@@ -52,6 +52,9 @@
 		box-sizing: @checkbox-box-box-sizing;
 		height: @checkbox-box-size;
 		position: @checkbox-box-position;
+		-webkit-transform: @checkbox-box-transform;
+		-moz-transform: @checkbox-box-transform;
+		-ms-transform: @checkbox-box-transform;
 		transform: @checkbox-box-transform;
 		transform-origin: @checkbox-box-transform-origin;
 		width: @checkbox-box-size;
@@ -65,6 +68,9 @@
 		height: @checkbox-check-height;
 		left: @checkbox-check-fix-left;
 		position: @checkbox-check-position;
+		-webkit-transform: @checkbox-check-transform;
+		-moz-transform: @checkbox-check-transform;
+		-ms-transform: @checkbox-check-transform;
 		transform: @checkbox-check-transform;
 		transform-origin: @checkbox-check-transform-origin;
 		width: @checkbox-check-height;
@@ -73,15 +79,21 @@
 	&.mui-checked {
 		.mui-checkbox-box {
 			.ease-out;
+			-webkit-transform: rotate(45deg) scale(0);
+			-moz-transform: rotate(45deg) scale(0);
+			-ms-transform: rotate(45deg) scale(0);
 			transform: rotate(45deg) scale(0);
 		}
 
 		.mui-checkbox-check {
 			.ease-out;
 			height: @checkbox-checked-check-height;
+			-webkit-transform: @checkbox-checked-check-transform;
+			-moz-transform: @checkbox-checked-check-transform;
+			-ms-transform: @checkbox-checked-check-transform;
 			transform: @checkbox-checked-check-transform;
 			transition-delay: @checkbox-checked-check-transition-delay;
 			width: @checkbox-checked-check-width;
 		}
 	}
-}
+}