fonts support, cleanup

src/components/rich_content/rich_content.scss

@@ -1,10 +1,10 @@
-@import "../../variables";
-
 .RichContent {
+  font-family: var(--font);
+
   blockquote {
     margin: 0.2em 0 0.2em 0.2em;
     font-style: italic;
-    border-left: 0.2em solid var(--faint, $fallback--faint);
+    border-left: 0.2em solid var(--textFaint);
     padding-left: 1em;
   }
 
@@ -17,7 +17,7 @@
   kbd,
   var,
   pre {
-    font-family: var(--postCodeFont, monospace);
+    font-family: var(--monoFont);
   }
 
   p {

src/components/rich_content/rich_content.style.js

@@ -9,6 +9,8 @@ export default {
   defaultRules: [
     {
       directives: {
+        '--font': 'generic | inherit',
+        '--monoFont': 'generic | monospace',
         textNoCssColor: 'yes'
       }
     }