add Table of Contents

- can be used by
     `ShowToc = true` in Single Post params

assets/css/main.css

@@ -44,4 +44,10 @@
     margin-left: auto;
     padding-left: 18px;
     padding-right: 16px;
+}
+
+.toc {
+    border-bottom: 1px solid var(--border);
+    font-size: 20px;
+    font-weight: 500;
 }

layouts/_default/single.html

@@ -12,6 +12,12 @@
       {{- .Date.Format "January 2, 2006" -}}
     </div>
   </header>
+  {{ if .Params.ShowToc }}
+  <blockquote>
+    <div class="toc">Table of Contents</div>
+    {{ .TableOfContents }}
+  </blockquote>
+  {{ end }}
   <div class="post-content">{{ .Content }}</div>
   {{- if .Params.tags }}
   <footer class="post-footer">