closes https://github.com/NodeBB/NodeBB/issues/4413

less/modules/composer-default.less

@@ -0,0 +1,17 @@
+.composer {
+	.preview {
+		overflow-y: auto;
+
+		p {
+			margin: 0 0 18px;
+		}
+		
+		blockquote {
+			font-size: 12px;
+			
+			p {
+				margin-bottom: 0px;
+			}
+		}
+	}
+}

less/persona.less

@@ -30,6 +30,7 @@
 @import "modules/alerts";
 @import "modules/fab";
 @import "modules/morph";
+@import "modules/composer-default";
 
 
 @material-primary:         #337ab7;