diff --git a/src/main.scss b/src/main.scss
index aca977a..a2ffc76 100644
--- a/src/main.scss
+++ b/src/main.scss
@@ -123,3 +123,54 @@
 .toc {
   padding-bottom: 10px;
 }
+
+.menu {
+  font-size: 1rem;
+}
+.menu.is-small {
+  font-size: 0.85em;
+}
+.menu.is-medium {
+  font-size: 1.25rem;
+}
+.menu.is-large {
+  font-size: 1.5rem;
+}
+
+.menu-list {
+  line-height: 1;
+  font-size: 0.9em;
+}
+.menu-list a {
+  border-radius: 3px;
+  color: #34495e;
+  display: block;
+  padding: 0.5em 0.75em;
+}
+.menu-list a:hover {
+  background-color: #ecf0f1;
+  color: #2b3c4e;
+}
+.menu-list a.is-active {
+  background-color: #1abc9c;
+  color: #fff;
+}
+.menu-list li ul {
+  border-left: 1px solid #dee2e5;
+  margin: 0.75em;
+  padding-left: 0.75em;
+}
+
+.menu-label {
+  color: #1abc9c;
+  font-size: 0.8em;
+  letter-spacing: 0.1em;
+  text-transform: uppercase;
+}
+.menu-label:not(:first-child) {
+  margin-top: 1em;
+}
+.menu-label:not(:last-child) {
+  margin-bottom: 0.5em;
+}
+