Media Gallery: Support for dark theme

ts/components/conversation/media-gallery/EmptyState.tsx

@@ -3,28 +3,14 @@
  */
 import React from 'react';
 
-import * as Colors from '../../styles/Colors';
-
 interface Props {
   label: string;
 }
 
-const styles = {
-  container: {
-    display: 'flex',
-    justifyContent: 'center',
-    alignItems: 'center',
-    flexGrow: 1,
-
-    fontSize: 28,
-    color: Colors.TEXT_SECONDARY,
-  } as React.CSSProperties,
-};
-
 export class EmptyState extends React.Component<Props> {
   public render() {
     const { label } = this.props;
 
-    return <div style={styles.container}>{label}</div>;
+    return <div className="module-empty-state">{label}</div>;
   }
 }