docs: Make links blue and underlined (#2264)

* docs: Make links blue and underlined

* docs: No blue or underlined links inside nav

docs/_static/custom.css

@@ -4,3 +4,11 @@
   --md-primary-fg-color--dark:  #000000;
   --md-footer-bg-color--dark:   #000000;
 }
+
+.md-content {
+  --md-typeset-a-color: var(--md-accent-fg-color);
+}
+
+.md-content a {
+  text-decoration: underline;
+}