Don't show "Join the conversation" to demo users

And minor style tweaks

src/styles/_comments.sass

@@ -18,11 +18,8 @@ $comments-width-max: 710px
 	#comments-list-header
 		#comments-list-title
 			padding: 15px 0 10px 0
-			margin: 0
-			font:
-				size: 1.5em
-				weight: 300
-				family: $font-body
+			font-size: 1.3em
+			font-weight: 300
 			color: $color-text-dark-primary
 
 	#comments-list-items-loading
@@ -416,19 +413,13 @@ $comments-width-max: 710px
 							border-color: $color-danger
 
 					&.sign-in
-						textarea
-							margin: 0
-
-						.sign-in
-							position: absolute
-							top: 0
-							left: 0
-							right: 0
-							bottom: 0
+						display: block
+						padding: 10px
+						border-radius: 3px
+						border: thin solid $color-background
 						background-color: rgba(white, .5)
-							display: flex
-							align-items: center
-							padding-left: 15px
+						color: $color-text-dark-primary
+						cursor: default
 
 						a
 							margin-right: 4px

src/templates/nodes/custom/comment/list_embed.jade

@@ -44,13 +44,7 @@
 			| {# * User is authenticated, but has no subscription or 'POST' permission #}
 			.comment-reply-form
 				.comment-reply-field.sign-in
-					textarea(
-						disabled,
-						id="comment_field",
-						data-parent-id="{{ node_id }}",
-						placeholder="")
-					.sign-in
-						| {% if current_user.has_role('subscriber') %}
+					| {% if current_user.has_role('subscriber') or current_user.has_role('demo') %}
 					i.pi-lock
 					|  Only project members can comment.
 					| {% else %}