diff --git a/phpBB/styles/prosilver/template/overall_header.html b/phpBB/styles/prosilver/template/overall_header.html
index 09824d0a16..cb1283cab4 100644
--- a/phpBB/styles/prosilver/template/overall_header.html
+++ b/phpBB/styles/prosilver/template/overall_header.html
@@ -61,10 +61,6 @@
 	<link href="{T_ASSETS_PATH}/cookieconsent/cookieconsent.min.css?assets_version={T_ASSETS_VERSION}" rel="stylesheet">
 <!-- ENDIF -->
 
-<!--[if lte IE 9]>
-	<link href="{T_THEME_PATH}/tweaks.css?assets_version={T_ASSETS_VERSION}" rel="stylesheet">
-<![endif]-->
-
 <!-- EVENT overall_header_head_append -->
 
 {$STYLESHEETS}
diff --git a/phpBB/styles/prosilver/template/simple_header.html b/phpBB/styles/prosilver/template/simple_header.html
index 905d25096f..d7a6e050e9 100644
--- a/phpBB/styles/prosilver/template/simple_header.html
+++ b/phpBB/styles/prosilver/template/simple_header.html
@@ -31,10 +31,6 @@
 	<link href="{T_THEME_PATH}/bidi.css?assets_version={T_ASSETS_VERSION}" rel="stylesheet">
 <!-- ENDIF -->
 
-<!--[if lte IE 8]>
-	<link href="{T_THEME_PATH}/tweaks.css?assets_version={T_ASSETS_VERSION}" rel="stylesheet">
-<![endif]-->
-
 <!-- DEFINE $POPUP = 1 -->
 
 <!-- EVENT simple_header_head_append -->
diff --git a/phpBB/styles/prosilver/theme/stylesheet.css b/phpBB/styles/prosilver/theme/stylesheet.css
index ddae99a94e..0da29846db 100644
--- a/phpBB/styles/prosilver/theme/stylesheet.css
+++ b/phpBB/styles/prosilver/theme/stylesheet.css
@@ -19,3 +19,4 @@
 @import url("icons.css?v=3.3");
 @import url("colours.css?v=3.3");
 @import url("responsive.css?v=3.3");
+@import url("tweaks.css?v=3.3");
diff --git a/phpBB/styles/prosilver/theme/tweaks.css b/phpBB/styles/prosilver/theme/tweaks.css
index d6328ae5f6..4b3b7afd24 100644
--- a/phpBB/styles/prosilver/theme/tweaks.css
+++ b/phpBB/styles/prosilver/theme/tweaks.css
@@ -1,61 +1,4 @@
 /* -------------------------------------------------------------- /*
 	$Tweaks
 /* -------------------------------------------------------------- /*
-	These style definitions are IE 8 & 9 only.
-	They are required due to the poor CSS support in IE browsers.
 /* -------------------------------------------------------------- */
-
-/* stylelint-disable selector-max-compound-selectors */
-/* stylelint-disable selector-no-qualifying-type */
-
-
-/* IE 8 Tweaks (value)\9 equates to  IE <= 8
------------------------------------------------------------------ */
-
-/* Clear float fix */
-.inner,
-ul.linklist {
-	zoom: 1\9;
-}
-
-/* Align checkboxes/radio buttons nicely */
-dd label input {
-	vertical-align: text-bottom\9;
-}
-
-/* Fixes header-avatar aspect-ratio */
-.header-avatar img {
-	height: 20px\9;
-}
-
-/* IE8 often can not handle max-width in %, so we use px instead */
-.postprofile .avatar img {
-	max-width: 150px\9;
-}
-
-
-/* IE 9 Tweaks
------------------------------------------------------------------ */
-
-/* Border-radius bleed fix in IE9 */
-.search-header,
-.search-header .inputbox,
-.search-header a.button {
-	border-radius: 0;
-}
-
-.headerbar,
-.forumbg {
-	background-image: url("./images/bg_header.gif");
-}
-
-.forabg {
-	background-image: url("./images/bg_list.gif");
-}
-
-.tabs .tab > a {
-	border-radius: 0;
-}
-
-/* stylelint-enable selector-max-compound-selectors */
-/* stylelint-enable selector-no-qualifying-type */