Comments: When editing, resize the textarea

Minor tweaks:
* Remove the 'editing' class after cancel/save
* Style <code>, <pre>, etc tags

src/styles/_comments.sass

@@ -99,13 +99,13 @@ $comments-width-max: 710px
 				+media-lg
 					max-width: $comments-width-max
 
+				border: thin solid transparent
 				color: darken($color-text, 10%)
 				font:
 					size: 1em
 					weight: normal
-				transition: background-color 200ms ease-in-out, margin 200ms ease-in-out
 				margin: 0
-				border: thin solid transparent
+				transition: background-color 200ms ease-in-out, margin 200ms ease-in-out
 
 				+media-xs
 					padding-left: 0
@@ -126,24 +126,28 @@ $comments-width-max: 710px
 					&.comment-author
 						margin-bottom: 0
 
-				strong, b
-					font-weight: bold
-					color: $color-text
-
 				img.emoji
+					display: inline-block
 					padding-top: inherit
 					padding-bottom: inherit
 
 				.editing
 					background-color: $color-background-light
-					margin-bottom: 10px
-					border-color: $color-background-dark
-					border-radius: 3px
+					display: flex
+					margin: 30px 0 10px
 
 					textarea
-						box-shadow: none
+						background-color: $color-background
+						border-radius: 3px
+						border: none
+						box-shadow: inset 0 0 2px 0 rgba(darken($color-background-dark, 30%), .5)
+						display: block
+						padding: 10px
 						width: 100%
 
+						&:focus
+							box-shadow: inset 0 0 2px 0 darken($color-background-dark, 30%)
+
 			.comment-content
 				display: flex
 				flex-direction: column