diff --git a/phpBB/styles/prosilver/theme/colours.css b/phpBB/styles/prosilver/theme/colours.css
index 46eaa999b5..5f2454ff00 100644
--- a/phpBB/styles/prosilver/theme/colours.css
+++ b/phpBB/styles/prosilver/theme/colours.css
@@ -1262,63 +1262,6 @@ fieldset.quick-login input.inputbox {
 	color: transparent;
 }
 
-
-/* form button styles */
-
-a.button1,
-input.button1,
-input.button3,
-a.button2,
-input.button2 {
-	background-color: #efefef; /* old browsers */ /* ff3.6+ */
-	background-image: linear-gradient(to bottom, #d2d2d2 0%, #efefef 100%); /* w3c */
-	color: #000000;
-	filter: progid:dximagetransform.microsoft.gradient(startcolorstr='#d2d2d2', endcolorstr='#efefef', gradienttype=0); /* ie6-9 */
-}
-
-a.button1,
-input.button1 {
-	border-color: #666666;
-}
-
-input.button3 {
-	background-image: none;
-}
-
-/* alternative button */
-a.button2,
-input.button2,
-input.button3 {
-	border-color: #666666;
-}
-
-/* <a> button in the style of the form buttons */
-a.button1,
-a.button2 {
-	color: #000000;
-}
-
-/* hover states */
-a.button1:hover,
-input.button1:hover,
-a.button2:hover,
-input.button2:hover,
-input.button3:hover {
-	background-color: #d2d2d2; /* old browsers */ /* ff3.6+ */
-	background-image: linear-gradient(to bottom, #efefef 0%, #d2d2d2 100%); /* w3c */
-	border-color: #d31141;
-	color: #d31141;
-	filter: progid:dximagetransform.microsoft.gradient(startcolorstr='#efefef', endcolorstr='#d2d2d2', gradienttype=0); /* ie6-9 */
-}
-
-/* focus states */
-input.button1:focus,
-input.button2:focus,
-input.button3:focus {
-	border-color: #11a3ea;
-	color: #0f4987;
-}
-
 input.disabled {
 	color: #666666;
 }
@@ -1411,4 +1354,3 @@ li.notification-disapproved strong {
 	color: #ffffff;
 }
 /* stylelint-enable */
-
diff --git a/phpBB/styles/prosilver/theme/common.css b/phpBB/styles/prosilver/theme/common.css
index c4eead7027..709515d38c 100644
--- a/phpBB/styles/prosilver/theme/common.css
+++ b/phpBB/styles/prosilver/theme/common.css
@@ -850,12 +850,6 @@ fieldset.fields1 dd.recipients {
 	margin-left: 1em;
 }
 
-fieldset.fields1 ul.recipients input.button2 {
-	font-size: 0.8em;
-	margin-right: 0;
-	padding: 0;
-}
-
 fieldset.fields1 dl.pmlist > dt {
 	width: auto !important;
 }
diff --git a/phpBB/styles/prosilver/theme/forms.css b/phpBB/styles/prosilver/theme/forms.css
index f4985f5508..5d24c7511c 100644
--- a/phpBB/styles/prosilver/theme/forms.css
+++ b/phpBB/styles/prosilver/theme/forms.css
@@ -341,41 +341,6 @@ input[type='search']::-webkit-search-cancel-button {
 	cursor: pointer;
 }
 
-/* Form button styles
----------------------------------------- */
-input.button1,
-input.button2 {
-	font-size: 1em;
-}
-
-a.button1,
-input.button1,
-input.button3,
-a.button2,
-input.button2 {
-	font-family: 'Lucida Grande', Verdana, Helvetica, Arial, sans-serif;
-	line-height: 1.5;
-	background: transparent none repeat-x top left;
-	width: auto !important;
-	padding-top: 1px;
-	padding-bottom: 1px;
-}
-
-a.button1,
-input.button1 {
-	font-weight: bold;
-	border: 1px solid transparent;
-}
-
-input.button3 {
-	font-variant: small-caps;
-	line-height: 5px;
-	background-image: none;
-	height: 12px;
-	margin: 0;
-	padding: 0;
-}
-
 input[type='button'],
 input[type='submit'],
 input[type='reset'],
@@ -384,41 +349,10 @@ input[type='radio'] {
 	cursor: pointer;
 }
 
-/* Alternative button */
-a.button2,
-input.button2,
-input.button3 {
-	border: 1px solid transparent;
-}
-
-/* <a> button in the style of the form buttons */
-a.button1,
-a.button2 {
-	text-decoration: none;
-	vertical-align: text-bottom;
-	padding: 0 3px;
-}
-
-/* Hover states */
-a.button1:hover,
-input.button1:hover,
-a.button2:hover,
-input.button2:hover,
-input.button3:hover {
-	border: 1px solid transparent;
-}
-
 input.disabled {
 	font-weight: normal;
 }
 
-/* Focus states */
-input.button1:focus,
-input.button2:focus,
-input.button3:focus {
-	outline-style: none;
-}
-
 /* Topic and forum Search */
 .search-box {
 	float: left;