fix code block flowing into float

content/common/kwant.css

@@ -87,6 +87,7 @@ img {
 }
 
 pre, code { background-color: #eee; border: 1px solid #ccc; }
+pre.literal-block { overflow: hidden }
 pre { padding: 0.3em; }
 code { padding: 0 0.1em; }
 pre > code { border: none; padding: 0; }