diff --git a/resources/skins.minerva.base.styles/ui.less b/resources/skins.minerva.base.styles/ui.less
index 23ff93c..beef00f 100644
--- a/resources/skins.minerva.base.styles/ui.less
+++ b/resources/skins.minerva.base.styles/ui.less
@@ -18,6 +18,7 @@ body {
 	// avoid margin collapsing (see T147956)
 	border-top: 1px solid transparent;
 	padding-bottom: 32px;
+	display: block; // T207618 - Define this <main> element for IE11 and under.
 }
 
 .overlay-enabled,