.X {background: #FFF} /* unidentified */
#digraphs .Xa {color: #0A0} /* ascii */
#digraphs .Xl {color: #070} /* latin1 */
-#digraphs .Xz {color: #D00} /* proposed */
+#digraphs .u-prop {color: #D00} /* proposed */
+#digraphs .u-prop.ex {color: #A44} /* experimental, disfavoured */
.Lm, .Mc, .Me, .Zl, .Zp {background: #F00} /* unstyled */
.X > span {background: #888} /* invisible contents */
.Xr:hover {background: #FFF} /* reserved */
.Xa:hover {outline: 1px solid #0F0} /* ascii */
.Xl:hover {outline: 1px solid #0C0} /* latin1 */
-.Xz:hover {outline: 1px solid #F00} /* proposed */
+.u-prop:hover {outline: 1px solid #F00} /* proposed */
.l0:hover {background: #888}
.l1:hover {background: #F88}
.l2:hover {background: #FC8}