Thử nghiệm bôi đen code

.thumbnail{position: relative;z-index: 0;}.thumbnail:hover{background-color: transparent;z-index: 50;}.thumbnail span{ /*CSS for enlarged image*/position: absolute;background-color: lightyellow;padding: 5px;left: -1000px;border: 1px dashed black;visibility: hidden;color: black;text-decoration: none;}.thumbnail span img{ /*CSS for enlarged image*/border-width: 0;padding: 2px;}.thumbnail:hover span{ /*CSS for enlarged image on hover*/visibility: visible;top: 0;left: 150px; /*position where enlarged image should offset horizontally */}