Fixed invalid HTML in workshop previews

app/assets/stylesheets/_application.scss

@@ -1748,20 +1748,31 @@ html[data-lingua-franca-example="html"] {
 		overflow: hidden;
 	}
 
-	> li {
-		margin-bottom: 1em;
-		border: 0.2em solid;
-		@include _(border-radius, 0.25em);
+	.workshop-link {
+		position: static;
 
-		> a {
+		@include before {
+			content: '';
 			display: block;
-			color: inherit;
-
+			position: absolute;
+			top: 0;
+			right: 0;
+			bottom: 0;
+			left: 0
+		}
 		@include after {
 			display: none;
 		}
 	}
 
+	> li {
+		position: relative;
+		margin-bottom: 1em;
+		border: 0.2em solid;
+		@include _(border-radius, 0.25em);
+		@include _(transition, box-shadow 250ms ease-in-out);
+		will-change: box-shadow;
+
 		ul {
 			padding-left: 2.5em;
 			margin-bottom: 1.5em;

app/views/workshops/_workshop_previews.html.haml

@@ -2,7 +2,7 @@
 	- workshops.sort_by{ |w| w.title.downcase }.each do |w|
 		- is_interested = w.interested?(current_user)
 		%li{class: [is_interested ? :interested : nil]}
-			= link_to view_workshop_path(w.conference.slug, w.id) do
+			= link_to view_workshop_path(w.conference.slug, w.id), class: 'workshop-link' do
 				%h4.title=w.title
 			.workshop-interest
 				- if is_interested