diff --git a/src/other/firefox/chrome/WhiteSur/parts/csd.css b/src/other/firefox/chrome/WhiteSur/parts/csd.css
index 35c5bbb..c0b4936 100644
--- a/src/other/firefox/chrome/WhiteSur/parts/csd.css
+++ b/src/other/firefox/chrome/WhiteSur/parts/csd.css
@@ -7,7 +7,7 @@
 }
 
 /* Headerbar top border corners rounded */
-:root[tabsintitlebar]:not([inFullscreen]) #nav-bar {
+:root[tabsintitlebar]:not([inFullscreen]):not([sizemode="maximized"]) #nav-bar {
 	border-radius: 16px 16px 0 0 !important;
 }
 
diff --git a/src/other/firefox/chrome/WhiteSur/rounded-window-maximized.css b/src/other/firefox/chrome/WhiteSur/rounded-window-maximized.css
new file mode 100644
index 0000000..ff05099
--- /dev/null
+++ b/src/other/firefox/chrome/WhiteSur/rounded-window-maximized.css
@@ -0,0 +1,5 @@
+@namespace xul url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
+
+:root[tabsintitlebar]:not([inFullscreen]) #nav-bar {
+	border-radius: 16px 16px 0 0;
+}
diff --git a/src/other/firefox/chrome/customChrome.css b/src/other/firefox/chrome/customChrome.css
new file mode 100644
index 0000000..6b97dd3
--- /dev/null
+++ b/src/other/firefox/chrome/customChrome.css
@@ -0,0 +1,3 @@
+
+/* Add your own custom styles here */
+
diff --git a/src/other/firefox/chrome/userChrome.css b/src/other/firefox/chrome/userChrome.css
index d9abb65..048ddbc 100644
--- a/src/other/firefox/chrome/userChrome.css
+++ b/src/other/firefox/chrome/userChrome.css
@@ -21,6 +21,9 @@
 /* Rounded title buttons (headerbar window controls) (GNOMISH) */
 /*@import "WhiteSur/rounded-title-buttons.css"; /**/
 
+/* Rounded window even when it gets maximized */
+/*@import "WhiteSur/rounded-window-maximized.css"; /**/
+
 /* Active tab high contrast */
 /*@import "WhiteSur/active-tab-contrast.css"; /**/