[css-align-3] Tweak table styling

Author: fantasai

css-align-3/Overview.bs

@@ -64,7 +64,12 @@ spec:css2; type:dfn; text:line box
 table small { display: block; }
 
 table.align-details { width: 100%; }
-.align-details th { font: inherit; white-space: nowrap; width: 1em; }
+.align-details th {
+	font: inherit;
+	font-style: italic;
+	white-space: nowrap; width: 1em;
+	vertical-align: baseline; }
+.align-details td { vertical-align: baseline; }
 </style>
 
 <h2 id="intro">