clean up description style

ui/component/common/markdown-preview.jsx

@@ -1,5 +1,6 @@
 // @flow
 import * as React from 'react';
+import classnames from 'classnames';
 import remark from 'remark';
 import remarkAttr from 'remark-attr';
 import remarkStrip from 'strip-markdown';
@@ -29,6 +30,7 @@ type MarkdownProps = {
   content: ?string,
   promptLinks?: boolean,
   noDataStore?: boolean,
+  className?: string,
 };
 
 const SimpleText = (props: SimpleTextProps) => {
@@ -97,7 +99,7 @@ schema.attributes.a.push('embed');
 const REPLACE_REGEX = /(<iframe\s+src=["'])(.*?(?=))(["']\s*><\/iframe>)/g;
 
 const MarkdownPreview = (props: MarkdownProps) => {
-  const { content, strip, promptLinks, noDataStore } = props;
+  const { content, strip, promptLinks, noDataStore, className } = props;
   const strippedContent = content
     ? content.replace(REPLACE_REGEX, (iframeHtml, y, iframeSrc) => {
         // Let the browser try to create an iframe to see if the markup is valid
@@ -151,7 +153,7 @@ const MarkdownPreview = (props: MarkdownProps) => {
   }
 
   return (
-    <div dir="auto" className="markdown-preview">
+    <div dir="auto" className={classnames('markdown-preview', className)}>
       {
         remark()
           .use(remarkAttr, remarkAttrOpts)

ui/component/fileDescription/view.jsx

@@ -32,7 +32,7 @@ class FileDescription extends PureComponent<Props> {
           <>
             {description && (
               <div className="media__info-text">
-                <MarkdownPreview content={description} />
+                <MarkdownPreview className="markdown-preview--description" content={description} />
               </div>
             )}
             <ClaimTags uri={uri} type="large" />

ui/scss/component/_markdown-preview.scss

@@ -20,6 +20,7 @@
   h6 {
     font-size: inherit;
     margin-bottom: var(--spacing-m);
+    font-weight: bold;
 
     &:not(:first-child) {
       margin-top: var(--spacing-l);
@@ -45,6 +46,27 @@
     font-size: 1em;
   }
 
+  &.markdown-preview--description {
+    h1 {
+      font-size: 1.2em;
+    }
+    h2 {
+      font-size: 1.1em;
+    }
+    h3 {
+      font-size: 1em;
+    }
+    h4 {
+      font-size: 0.9em;
+    }
+    h5 {
+      font-size: 0.8em;
+    }
+    h6 {
+      font-size: 0.7em;
+    }
+  }
+
   dl,
   ul,
   ol,