Fix background color declaration.

static/api.css

@@ -66,10 +66,13 @@ table.parameters th {
 table.parameters tr:first-child {
     font-family: sans-serif;
     font-size: 1.17em;
-    background-color: #369;
     color: white;
 }
 
+table.parameters tr:first-child td {
+    background-color: #369;
+}
+
 table.parameters td:first-child {
     font-family: monospace;
 }