diff --git a/core/modules/forum/css/forum.theme.css b/core/modules/forum/css/forum.theme.css
index e7490f2..9e2ef5d 100644
--- a/core/modules/forum/css/forum.theme.css
+++ b/core/modules/forum/css/forum.theme.css
@@ -3,19 +3,19 @@
  * Styling for the Forum module.
  */
 
-#forum .description {
+.forum__description {
   font-size: 0.9em;
   margin: 0.5em;
 }
-#forum td.created,
-#forum td.posts,
-#forum td.topics,
-#forum td.last-reply,
-#forum td.replies,
-#forum td.pager {
+.forum__created,
+.forum__posts,
+.forum__topics,
+.forum__last-reply,
+.forum__replies,
+.forum__pager {
   white-space: nowrap;
 }
-#forum .icon{
+.forum__icon {
   background-image: url(../icons/forum-icons.png);
   background-repeat: no-repeat;
   float: left; /* LTR */
@@ -23,11 +23,11 @@
   margin: 0 9px 0 0; /* LTR */
   width: 24px;
 }
-[dir="rtl"] #forum .icon {
+[dir="rtl"] .forum__icon {
   float: right;
   margin: 0 0 0 9px;
 }
-#forum .title {
+.forum__title {
   overflow: hidden;
 }
 #forum div.indent {
@@ -37,31 +37,30 @@
   margin-left: 0;
   margin-right: 20px;
 }
-
-#forum .topic-status-new {
+.forum__topic-status--new {
   background-position: -24px 0;
 }
-#forum .topic-status-hot {
+.forum__topic-staus--hot {
   background-position: -48px 0;
 }
-#forum .topic-status-hot-new {
+.forum__topic-staus--hot-new {
   background-position: -72px 0;
 }
-#forum .topic-status-sticky {
+.forum__topic-staus--sticky {
   background-position: -96px 0;
 }
-#forum .topic-status-closed {
+.forum__topic-staus--closed {
   background-position: -120px 0;
 }
 
 [dir="rtl"] .forum-topic-navigation {
   padding: 1em 3em 0 0;
 }
-[dir="rtl"] .forum-topic-navigation .topic-previous {
+[dir="rtl"] .forum-topic-navigation__previous {
   text-align: left;
   float: right;
 }
-[dir="rtl"] .forum-topic-navigation .topic-next {
+[dir="rtl"] .forum-topic-navigation__next {
   text-align: right;
   float: left;
 }