style(nix/floorp): Vertical tab is too small on my thinkpad setup

.config/nix/files/floorp/userChrome.css

@@ -16,7 +16,7 @@
   /*--hoverd-verticaltab-width: 20em;*/
 
   --default-verticaltab-width: 4.125em !important;
-  --hoverd-verticaltab-width: 18em;
+  --hoverd-verticaltab-width: /*ZI:VERTICAL-TAB-HOVER-WIDTH-IN-EM*/ !important;
 }
 
 @charset "UTF-8";

.config/nix/flake.nix

@@ -4,6 +4,9 @@
   outputs = inputs@{ self, nix-darwin, nixpkgs, home-manager, system-manager, ... }:
   let
     vars = {
+      floorp = {
+        verticalTabHoverWidthInEm = 18;
+      };
       rev = self.rev or self.dirtyRev or null;
     };
   in

.config/nix/modules/home-manager/floorp.nix

@@ -6,7 +6,7 @@
     # REF: https://github.com/nix-community/home-manager/blob/342a1d682386d3a1d74f9555cb327f2f311dda6e/modules/programs/firefox/mkFirefoxModule.nix#L264
     package = null;  # we only want the config
     profiles.${vars.name} = {
-      userChrome = builtins.readFile ../../files/floorp/userChrome.css;
+      userChrome = builtins.replaceStrings ["/*ZI:VERTICAL-TAB-HOVER-WIDTH-IN-EM*/"] ["${builtins.toString vars.floorp.verticalTabHoverWidthInEm}em"] (builtins.readFile ../../files/floorp/userChrome.css);
       settings = {
         "browser.toolbars.bookmarks.visibility" = "newtab";
         "floorp.browser.sidebar.is.displayed" = false;

.config/nix/users/default.nix

@@ -20,6 +20,7 @@ in
     let
       inherit (mkSystem "x86_64-darwin" nixpkgs [inputs.firefox-darwin.overlay]) system pkgs;
       vars.name = "ziro";
+      vars.floorp.verticalTabHoverWidthInEm = 30;
     in
     home-manager.lib.homeManagerConfiguration {
       inherit pkgs;