diff --git a/phpBB/adm/style/admin.css b/phpBB/adm/style/admin.css
index a71d55a499..50d55cad17 100644
--- a/phpBB/adm/style/admin.css
+++ b/phpBB/adm/style/admin.css
@@ -1707,26 +1707,26 @@ fieldset.submit-buttons legend {
 	flex-shrink: 0;
 	justify-content: center;
 	align-items: center;
-	margin-right: 10px;
+	margin-right: 16px;
 	margin-left: 0;
 }
 
 .rtl .mention-media {
 	margin-right: 0;
-	margin-left: 10px;
+	margin-left: 16px;
 }
 
 .mention-media-avatar {
-	font-size: 32px;
-	line-height: 36px;
-	text-align: center;
-	vertical-align: center;
-	width: 36px;
-	height: 36px;
+	width: 40px;
+	height: 40px;
+}
+
+svg.mention-media-avatar { /* TODO: remove it after general normalization */
+	fill: currentColor;
 }
 
 .mention-item {
-	font-size: 14px;
+	font-size: 16px;
 	font-weight: 400;
 	line-height: 1.5;
 	letter-spacing: 0.04em;
@@ -1738,7 +1738,7 @@ fieldset.submit-buttons legend {
 	justify-content: flex-start;
 	align-items: center;
 	max-width: 300px;
-	padding: 10px;
+	padding: 16px;
 	cursor: pointer;
 }
 
@@ -1764,7 +1764,7 @@ fieldset.submit-buttons legend {
 }
 
 .mention-rank {
-	font-size: 12px;
+	font-size: 14px;
 	font-weight: 400;
 	line-height: 1.2871;
 	letter-spacing: 0.04em;
diff --git a/phpBB/assets/javascript/editor.js b/phpBB/assets/javascript/editor.js
index c80d47ddf8..076b7fd7ff 100644
--- a/phpBB/assets/javascript/editor.js
+++ b/phpBB/assets/javascript/editor.js
@@ -385,6 +385,10 @@ function getCaretPosition(txtarea) {
 }
 
 (function($) {
+	function mention_default_avatar(type) {
+		return (type === 'group') ? '<svg class="mention-media-avatar" xmlns="http://www.w3.org/2000/svg" viewbox="0 0 24 24"><path fill-rule="evenodd" d="M16 11c1.66 0 2.99-1.34 2.99-3S17.66 5 16 5c-1.66 0-3 1.34-3 3s1.34 3 3 3zm-8 0c1.66 0 2.99-1.34 2.99-3S9.66 5 8 5C6.34 5 5 6.34 5 8s1.34 3 3 3zm0 2c-2.33 0-7 1.17-7 3.5V19h14v-2.5c0-2.33-4.67-3.5-7-3.5zm8 0c-.29 0-.62.02-.97.05 1.16.84 1.97 1.97 1.97 3.45V19h6v-2.5c0-2.33-4.67-3.5-7-3.5z"/></svg>' : '<svg class="mention-media-avatar" xmlns="http://www.w3.org/2000/svg" viewbox="0 0 24 24"><path fill-rule="evenodd" d="M12,19.2C9.5,19.2 7.29,17.92 6,16C6.03,14 10,12.9 12,12.9C14,12.9 17.97,14 18,16C16.71,17.92 14.5,19.2 12,19.2M12,5A3,3 0 0,1 15,8A3,3 0 0,1 12,11A3,3 0 0,1 9,8A3,3 0 0,1 12,5M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12C22,6.47 17.5,2 12,2Z"/></svg>';
+	}
+
 	function handle_mentions(txtarea) {
 		var $mentionDataContainer = $('[data-mention-url]'),
 			mentionURL = $mentionDataContainer.data('mentionUrl'),
@@ -393,8 +397,7 @@ function getCaretPosition(txtarea) {
 		$(txtarea).atwho({
 			at: "@",
 			displayTpl: function(data) {
-				var avatar = (data.avatar.src) ? "<img src='" + data.avatar.src + "' class='mention-media-avatar'>" :
-					"<i class='mention-media-avatar fa fa-" + data.avatar.type + "'></i>",
+				var avatar = (data.avatar.src) ? "<img src='" + data.avatar.src + "' class='mention-media-avatar'>" : mention_default_avatar(data.avatar.type),
 					rank = (data.rank) ? "<span class='mention-rank'>" + data.rank + "</span>" : '';
 				return "<li class='mention-item'><span class='mention-media'>" + avatar + "</span><span class='mention-name'>" + data.name + rank + "</span></li>";
 			},
diff --git a/phpBB/styles/prosilver/theme/bidi.css b/phpBB/styles/prosilver/theme/bidi.css
index 5a3286da56..7f9642b7cc 100644
--- a/phpBB/styles/prosilver/theme/bidi.css
+++ b/phpBB/styles/prosilver/theme/bidi.css
@@ -380,7 +380,7 @@
 
 .rtl .mention-media {
 	margin-right: 0;
-	margin-left: 10px;
+	margin-left: 16px;
 }
 
 /**
diff --git a/phpBB/styles/prosilver/theme/mentions.css b/phpBB/styles/prosilver/theme/mentions.css
index 01146e1128..32c77b196c 100644
--- a/phpBB/styles/prosilver/theme/mentions.css
+++ b/phpBB/styles/prosilver/theme/mentions.css
@@ -34,21 +34,21 @@
 	flex-shrink: 0;
 	justify-content: center;
 	align-items: center;
-	margin-right: 10px;
+	margin-right: 16px;
 	margin-left: 0;
 }
 
 .mention-media-avatar {
-	font-size: 32px;
-	line-height: 36px;
-	text-align: center;
-	vertical-align: center;
-	width: 36px;
-	height: 36px;
+	width: 40px;
+	height: 40px;
+}
+
+svg.mention-media-avatar { /* TODO: remove it after general normalization */
+	fill: currentColor;
 }
 
 .mention-item {
-	font-size: 14px;
+	font-size: 16px;
 	font-weight: 400;
 	line-height: 1.5;
 	letter-spacing: 0.04em;
@@ -59,7 +59,7 @@
 	justify-content: flex-start;
 	align-items: center;
 	max-width: 300px;
-	padding: 10px;
+	padding: 16px;
 	cursor: pointer;
 }
 
@@ -77,7 +77,7 @@
 }
 
 .mention-rank {
-	font-size: 12px;
+	font-size: 14px;
 	font-weight: 400;
 	line-height: 1.2871;
 	letter-spacing: 0.04em;