Add text variant

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

assets/css/lib/tocbot.css

@@ -0,0 +1,19 @@
+.toc ol {
+  counter-reset: item;
+  list-style: decimal;
+  line-height: 1.25;
+}
+
+.toc li:before {
+  content: counters(item, ".") " ";
+  counter-increment: item;
+}
+
+a.toc-link {
+  text-decoration: none;
+  font-weight: normal;
+}
+
+.toc>.toc-list li {
+  list-style: none
+}