diff --git a/chrome/centered_tab_content.css b/chrome/centered_tab_content.css
new file mode 100644
index 0000000..aa34e22
--- /dev/null
+++ b/chrome/centered_tab_content.css
@@ -0,0 +1,8 @@
+/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/centered_tab_content.css made available under Mozilla Public License v. 2.0
+See the above repository for updates as well as full license text. */
+
+.tab-content:not([pinned])::before{
+  display: -moz-box;
+  content: "";
+  -moz-box-flex: 1;
+}
\ No newline at end of file
diff --git a/html_resources/tagmap.json b/html_resources/tagmap.json
index 0c9c2e0..e177541 100644
--- a/html_resources/tagmap.json
+++ b/html_resources/tagmap.json
@@ -111,5 +111,6 @@
 "theme_aware_modal_prompts.css":["effect","dark-mode","colors","popup"],
 "centered_top_statuspanel.css":["status"],
 "custom_menupopup_check_icons.css":["icon","menu","minimal","popup"],
-"show_toolbars_in_popup_windows.css":["toolbars","popup"]
+"show_toolbars_in_popup_windows.css":["toolbars","popup"],
+"centered_tab_content.css":["tab","icon"]
 }
diff --git a/tags.csv b/tags.csv
index 0496940..aed142b 100644
--- a/tags.csv
+++ b/tags.csv
@@ -111,3 +111,4 @@ theme_aware_modal_prompts.css,effect,dark-mode,colors,popup
 centered_top_statuspanel.css,status
 custom_menupopup_check_icons.css,icon,menu,minimal,popup
 show_toolbars_in_popup_windows.css,toolbars,popup
+centered_tab_content.css,tab,icon