replaced table

docs/stylesheets/extra.css

@@ -47,3 +47,13 @@ footer a:hover {
     line-height: 1.6;
     color: var(--md-footer-fg-color--light);
 }
+
+.md-typeset thead th {
+    background-color: #ecf3ff; /*rgba(69, 84, 107, 0.5);*/
+    color: black;
+    font-size: 0.74rem;
+    border-bottom-color: black;
+    border-bottom-width: 2px;
+    border-bottom-style: solid;
+    font-style: normal;
+  }