Style support for (potential) code walkthrough pages

style.css

@@ -82,7 +82,7 @@ h1, h2, h3, h4, h5, h6 {
     font-family: {{ page.headerfonts }};
 }
 
-h1, h2, h3 {
+h1, h2, h3, h4 {
     margin-top: 1em;
     color: {{ page.headercolor }};
     font-weight: normal;
@@ -104,6 +104,13 @@ h3 {
     font-size: 1.4em;
 }
 
+h4 {
+    font-size: 1.2em;
+}
+h4 + p {
+    margin-top: 0.5em;
+}
+
 p, ul, ol {
     margin-top: 1em;
     line-height: 1.3em;
@@ -188,6 +195,10 @@ hr {
     margin-left: -3rem;
 }
 
+.content h4 {
+    margin-left: -1rem;
+}
+
 .content .entry_footer {
     text-align: right;
 }