.collapsible {background-color: #616161;color: white;cursor: pointer;padding: 18px;width: 100%;border: none;text-align: left;outline: none;font-size: 15px;}
.active, .collapsible:hover {background-color: #9e9e9e;}
.content {padding: 0 18px;background-color: white;max-height: 0;overflow: hidden;transition: max-height 0.2s ease-out;}
.collapsible:after {content: '+'; /*'\02795';  Unicode character for "plus" sign (+) */font-size: 13px;color: white;float: right;margin-left: 5px;}
.active:after {content: '-' /*"\2796";  Unicode character for "minus" sign (-) */}