Issue #1817996 by dead_arm: Added sane default styles for table <caption>.

core/modules/system/system.theme-rtl.css

@@ -12,6 +12,9 @@ th {
   padding-left: 1em;
   padding-right: 0;
 }
+caption {
+  text-align: right;
+}
 
 /**
  * Markup generated by theme_item_list().

core/modules/system/system.theme.css

@@ -37,6 +37,9 @@ tr {
   border-bottom: 1px solid #ccc;
   padding: 0.1em 0.6em;
 }
+caption {
+  text-align: left; /* LTR */
+}
 
 /**
  * Publishing status.

core/themes/bartik/css/style-rtl.css

@@ -1,6 +1,5 @@
 /* ------------------ Reset Styles ------------------ */
 
-caption,
 th,
 td {
   text-align: right;

core/themes/bartik/css/style.css

@@ -134,10 +134,6 @@ a.button {
 
 /* ------------------ Reset Styles ------------------ */
 
-caption {
-  text-align: left; /* LTR */
-  font-weight: normal;
-}
 blockquote {
   background: #f7f7f7;
   border-left: 1px solid #bbb;