CSS: Style the <pre> block

Fixes: #21

Author: encukou

static/style.css

@@ -174,3 +174,19 @@ footer a {
         margin-left: 1rem;
     }
 }
+
+pre {
+    background-color: #e4e6e8;
+    border: 1px solid rgba(0, 0, 0, 0.2);
+    box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.05);
+    border-radius: 4px;
+    padding: 0.5em;
+    margin-top: 0.5em;
+    margin-bottom: 0.5em;
+    margin-left: -0.5em;
+    margin-right: -0.5em;
+}
+
+code {
+    font-family: monospace;
+}