Fix padding for multiline code blocks

sass/_markdown.scss

@@ -22,10 +22,14 @@
   color: #4a4a4a;
   font-size: .875em;
   font-weight: normal;
-  padding: 0.25em 0.5em 0.25em;
+  padding: 0.25em 0.5em;
   font-family: monospace;
 }
 
+.content pre code {
+  padding: 0;
+}
+
 .content a {
   color: var(--primary-link-color);
 
@@ -39,4 +43,4 @@
   margin: 0;
   background-color: #f2f1f0;
   padding: 0 20px;
-}
+}