gallery.css

:root {
  --thumb-width: 160px;
  --thumb-height: 160px;
}
        .thumbs {
         color: white;
         background-color: grey;
        }
        a > .thumb { color: #fff; }
        .thumb {
          border-radius: 10px;
          background-color: black;
          position: relative;
          display: inline-block;
          width:var(--thumb-width); height:var(--thumb-height);
          margin: 4px;
          padding: 8px;
          cursor: pointer;
          overflow: hidden;
        }
	.folder {
          border-style: solid;
          border-width: 1px;
          border-color: #CCCCCC;
        }
       .caption {
         text-align: center;
         font-size: 80%;
         font-family: Helvetica, Arial, Sans-Serif;
         text-shadow: 1px 0 0 #000, 0 -1px 0 #000, 0 1px 0 #000, -1px 0 0 #000;
         position: absolute;
         width:var(--thumb-width);
         bottom:0px;
       }
       .thumbicon {
         position: absolute;
         font-size:48px;
         left:50%;
         top:50%;
         transform: translateX(-50%) translateY(-50%);
       }
       .thumbimage {
          width:var(--thumb-width); height:var(--thumb-height);
          background-position: center;
          background-repeat: no-repeat;
          background-size: contain;
       }