/* foreground representation */
#digraphs .u-l3 {color: #080} /* partial */
+#digraphs .u-l3.ex {color: #4C0} /* experimental */
#digraphs .u-l2 {color: #A44; color: rgba(128, 0, 0, .6)} /* unofficial proposal */
#digraphs .u-l1 {color: #D00; color: rgba(255, 0, 0, .8)} /* minimal or invalid */
.l3:hover {background: #FF8}
.l4:hover {background: #CF8}
.l5:hover {background: #8F8}
-.u-l3:hover {outline: 1px solid #0F0}
+.u-l3:hover {outline: 1px solid #080}
+.u-l3.ex:hover {outline: 1px solid #8F0}
.u-l2:hover {outline: 1px solid #800}
.u-l1:hover {outline: 1px solid #F00}