[css-color-4] Force a text color for the deltaE table, as the chosen colors are light and assume black text

Author: tabatkins

css-color-4/Overview.bs

@@ -121,7 +121,7 @@ table.named-color-table td:nth-child(-n+2) { border:1px solid var(--text); }
 .color-table th { white-space: pre-line; }
 .color-table td {	padding: .75em; }
 .color-table .white { color: white; }
-table.deltaE td {border: 4px solid white; padding: 6px; font-size: 1.4em;}
+table.deltaE td {border: 4px solid white; padding: 6px; font-size: 1.4em; color: black;}
 table.deltaE td.dE0 { background: rgb(68, 243, 91)}
 table.deltaE td.dE1 { background: rgb(153, 243, 68)}
 table.deltaE td.dE2 { background: rgb(217, 243, 68)}