#gallery {font: x-small sans-serif; width: 642px; text-align: right;}
#gallery div {margin: 1em 0;}
img {display: block; width: 640px; height: 64px; 
  border: 1px solid #777;}
span {display: inline-block; color: #999;
  border: 1px solid #999; border-top: none;
  padding: 0.33em 0.66em;}
span.num {border-left: none; background: #E2E2E2;}
#gallery div:hover span {color: #000; font-weight: bold;}