css--設置整塊灰色圖片，文字等

.gray {     
	 -webkit-filter: grayscale(100%);   
  	-moz-filter: grayscale(100%);  
  	-ms-filter: grayscale(100%);   
  	-o-filter: grayscale(100%);     
    filter: grayscale(100%); 	
    filter: gray;
   }