grayscale hover

 .post {
    filter: url(http://static.tumblr.com/eptm5us/ueTmafr4p/filters.svg#grayscale); /* Firefox 3.5+ */
    filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale"); /* Firefox 10+, IE10 */

    filter: gray; /* IE6-9 */
    -webkit-filter: grayscale(0%); /* Chrome 19+ & Safari 6+ */
    -webkit-transition: all .7s ease; /* Fade to color for Chrome and Safari */
    -webkit-backface-visibility: hidden; /* Fix for transition flickering */}

.post:hover {
    filter: none;
    -webkit-filter: grayscale(85%);}

/* Permalinks and Tags */