improve button style

style/components/button.less

@@ -101,22 +101,25 @@
   &-clicked:before {
   	content: '';
   	position: absolute;
-  	top: -6px;
-  	left: -6px;
-  	bottom: -6px;
-  	right: -6px;
+  	top: 0;
+  	left: 0;
+  	bottom: 0;
+  	right: 0;
   	border-radius: inherit;
   	z-index: -1;
-    background: inherit;
-  	opacity: 1;
-  	transform: scale3d(0.5, 0.5, 1);
-    animation: buttonEffect 0.48s ease forwards;
+    border: 0 solid @primary-color;
+  	opacity: 0.44;
+    animation: buttonEffect 0.36s ease forwards;
   }
 }
 
 @keyframes buttonEffect {
 	to {
 		opacity: 0;
-		transform: scale3d(1, 1, 1);
+    top: -6px;
+  	left: -6px;
+  	bottom: -6px;
+  	right: -6px;
+    border-width: 6px;
 	}
 }

style/mixins/button.less

@@ -77,6 +77,7 @@
   cursor: pointer;
   background-image: none;
   border: 1px solid transparent;
+  font-weight: 500;
   // outline: none;
   white-space: nowrap;
   line-height: @line-height-base;