diff --git a/modules/themes/alucard/README.org b/modules/themes/alucard/README.org
new file mode 100644
index 00000000..d6f512dd
--- /dev/null
+++ b/modules/themes/alucard/README.org
@@ -0,0 +1,14 @@
+#+TITLE:  Alucard
+#+AUTHOR: Henrik Lissner
+#+DATE:   October 1, 2019
+
+A regal dracula-inspired theme for piles of miserable secrets.
+
+* Wallpaper
+![Alucard wallpaper](config/wallpaper.jpg)
+
+* Screenshots
+![My desktop, pretending to look busy, with gaps](/../screenshots/alucard/fakebusy.png?raw=true)
+![My desktop, unfettered by windows](/../screenshots/alucard/desktop.png?raw=true)
+![My app launcher, rofi](/../screenshots/alucard/rofi.png?raw=true)
+![The gapless experience](/../screenshots/alucard/tiling.png?raw=true)
diff --git a/modules/themes/fluorescence/config/Xresources b/modules/themes/alucard/config/Xresources
similarity index 100%
rename from modules/themes/fluorescence/config/Xresources
rename to modules/themes/alucard/config/Xresources
diff --git a/modules/themes/fluorescence/config/bspwmrc b/modules/themes/alucard/config/bspwmrc
similarity index 100%
rename from modules/themes/fluorescence/config/bspwmrc
rename to modules/themes/alucard/config/bspwmrc
diff --git a/modules/themes/fluorescence/config/dunstrc b/modules/themes/alucard/config/dunstrc
similarity index 100%
rename from modules/themes/fluorescence/config/dunstrc
rename to modules/themes/alucard/config/dunstrc
diff --git a/modules/themes/fluorescence/config/firefox/userChrome.css b/modules/themes/alucard/config/firefox/userChrome.css
similarity index 100%
rename from modules/themes/fluorescence/config/firefox/userChrome.css
rename to modules/themes/alucard/config/firefox/userChrome.css
diff --git a/modules/themes/fluorescence/config/inkscape/default-template.svg b/modules/themes/alucard/config/inkscape/default-template.svg
similarity index 100%
rename from modules/themes/fluorescence/config/inkscape/default-template.svg
rename to modules/themes/alucard/config/inkscape/default-template.svg
diff --git a/modules/themes/fluorescence/config/polybar/config b/modules/themes/alucard/config/polybar/config
similarity index 100%
rename from modules/themes/fluorescence/config/polybar/config
rename to modules/themes/alucard/config/polybar/config
diff --git a/modules/themes/fluorescence/config/polybar/modules/redshift b/modules/themes/alucard/config/polybar/modules/redshift
similarity index 100%
rename from modules/themes/fluorescence/config/polybar/modules/redshift
rename to modules/themes/alucard/config/polybar/modules/redshift
diff --git a/modules/themes/fluorescence/config/polybar/run.sh b/modules/themes/alucard/config/polybar/run.sh
similarity index 100%
rename from modules/themes/fluorescence/config/polybar/run.sh
rename to modules/themes/alucard/config/polybar/run.sh
diff --git a/modules/themes/fluorescence/config/rofi/appmenu.rasi b/modules/themes/alucard/config/rofi/appmenu.rasi
similarity index 100%
rename from modules/themes/fluorescence/config/rofi/appmenu.rasi
rename to modules/themes/alucard/config/rofi/appmenu.rasi
diff --git a/modules/themes/fluorescence/config/rofi/base.cyclemenu.rasi b/modules/themes/alucard/config/rofi/base.cyclemenu.rasi
similarity index 100%
rename from modules/themes/fluorescence/config/rofi/base.cyclemenu.rasi
rename to modules/themes/alucard/config/rofi/base.cyclemenu.rasi
diff --git a/modules/themes/fluorescence/config/rofi/bookmarkmenu.rasi b/modules/themes/alucard/config/rofi/bookmarkmenu.rasi
similarity index 100%
rename from modules/themes/fluorescence/config/rofi/bookmarkmenu.rasi
rename to modules/themes/alucard/config/rofi/bookmarkmenu.rasi
diff --git a/modules/themes/fluorescence/config/rofi/config.rasi b/modules/themes/alucard/config/rofi/config.rasi
similarity index 100%
rename from modules/themes/fluorescence/config/rofi/config.rasi
rename to modules/themes/alucard/config/rofi/config.rasi
diff --git a/modules/themes/fluorescence/config/rofi/filemenu.rasi b/modules/themes/alucard/config/rofi/filemenu.rasi
similarity index 100%
rename from modules/themes/fluorescence/config/rofi/filemenu.rasi
rename to modules/themes/alucard/config/rofi/filemenu.rasi
diff --git a/modules/themes/fluorescence/config/rofi/passmenu.rasi b/modules/themes/alucard/config/rofi/passmenu.rasi
similarity index 100%
rename from modules/themes/fluorescence/config/rofi/passmenu.rasi
rename to modules/themes/alucard/config/rofi/passmenu.rasi
diff --git a/modules/themes/fluorescence/config/rofi/powermenu.rasi b/modules/themes/alucard/config/rofi/powermenu.rasi
similarity index 100%
rename from modules/themes/fluorescence/config/rofi/powermenu.rasi
rename to modules/themes/alucard/config/rofi/powermenu.rasi
diff --git a/modules/themes/fluorescence/config/rofi/windowmenu.rasi b/modules/themes/alucard/config/rofi/windowmenu.rasi
similarity index 100%
rename from modules/themes/fluorescence/config/rofi/windowmenu.rasi
rename to modules/themes/alucard/config/rofi/windowmenu.rasi
diff --git a/modules/themes/fluorescence/config/tmux.conf b/modules/themes/alucard/config/tmux.conf
similarity index 100%
rename from modules/themes/fluorescence/config/tmux.conf
rename to modules/themes/alucard/config/tmux.conf
diff --git a/modules/themes/fluorescence/config/userstyles/firefox/stylus-2020-02-11.json b/modules/themes/alucard/config/userstyles/firefox/stylus-2020-02-11.json
similarity index 100%
rename from modules/themes/fluorescence/config/userstyles/firefox/stylus-2020-02-11.json
rename to modules/themes/alucard/config/userstyles/firefox/stylus-2020-02-11.json
diff --git a/modules/themes/fluorescence/config/userstyles/qutebrowser/github.scss b/modules/themes/alucard/config/userstyles/qutebrowser/github.scss
similarity index 100%
rename from modules/themes/fluorescence/config/userstyles/qutebrowser/github.scss
rename to modules/themes/alucard/config/userstyles/qutebrowser/github.scss
diff --git a/modules/themes/fluorescence/config/userstyles/qutebrowser/monospace-textareas.scss b/modules/themes/alucard/config/userstyles/qutebrowser/monospace-textareas.scss
similarity index 100%
rename from modules/themes/fluorescence/config/userstyles/qutebrowser/monospace-textareas.scss
rename to modules/themes/alucard/config/userstyles/qutebrowser/monospace-textareas.scss
diff --git a/modules/themes/fluorescence/config/userstyles/qutebrowser/quora.scss b/modules/themes/alucard/config/userstyles/qutebrowser/quora.scss
similarity index 100%
rename from modules/themes/fluorescence/config/userstyles/qutebrowser/quora.scss
rename to modules/themes/alucard/config/userstyles/qutebrowser/quora.scss
diff --git a/modules/themes/fluorescence/config/userstyles/qutebrowser/stackoverflow.scss b/modules/themes/alucard/config/userstyles/qutebrowser/stackoverflow.scss
similarity index 100%
rename from modules/themes/fluorescence/config/userstyles/qutebrowser/stackoverflow.scss
rename to modules/themes/alucard/config/userstyles/qutebrowser/stackoverflow.scss
diff --git a/modules/themes/fluorescence/config/userstyles/qutebrowser/xkcd.scss b/modules/themes/alucard/config/userstyles/qutebrowser/xkcd.scss
similarity index 100%
rename from modules/themes/fluorescence/config/userstyles/qutebrowser/xkcd.scss
rename to modules/themes/alucard/config/userstyles/qutebrowser/xkcd.scss
diff --git a/modules/themes/fluorescence/config/userstyles/qutebrowser/youtube.scss b/modules/themes/alucard/config/userstyles/qutebrowser/youtube.scss
similarity index 100%
rename from modules/themes/fluorescence/config/userstyles/qutebrowser/youtube.scss
rename to modules/themes/alucard/config/userstyles/qutebrowser/youtube.scss
diff --git a/modules/themes/fluorescence/config/wallpaper.png b/modules/themes/alucard/config/wallpaper.png
similarity index 100%
rename from modules/themes/fluorescence/config/wallpaper.png
rename to modules/themes/alucard/config/wallpaper.png
diff --git a/modules/themes/fluorescence/config/zsh/prompt.zsh b/modules/themes/alucard/config/zsh/prompt.zsh
similarity index 100%
rename from modules/themes/fluorescence/config/zsh/prompt.zsh
rename to modules/themes/alucard/config/zsh/prompt.zsh
diff --git a/modules/themes/alucard/default.nix b/modules/themes/alucard/default.nix
new file mode 100644
index 00000000..fad85f10
--- /dev/null
+++ b/modules/themes/alucard/default.nix
@@ -0,0 +1,99 @@
+# modules/themes/alucard/default.nix --- a regal dracula-inspired theme
+
+{ options, config, lib, pkgs, ... }:
+
+with lib;
+with lib.my;
+let cfg = config.modules.theme;
+in {
+  config = mkIf (cfg.active == "alucard") (mkMerge [
+    # Desktop-agnostic configuration
+    {
+      modules = {
+        theme = {
+          wallpaper = mkDefault ./config/wallpaper.png;
+          gtk = {
+            theme = "Dracula";
+            iconTheme = "Paper";
+            cursorTheme = "Paper";
+          };
+        };
+
+        shell.zsh.rcFiles  = [ ./config/zsh/prompt.zsh ];
+        shell.tmux.rcFiles = [ ./config/tmux.conf ];
+        desktop.browsers = {
+          firefox.userChrome = concatMapStringsSep "\n" readFile [
+            ./config/firefox/userChrome.css
+          ];
+          qutebrowser.userStyles = concatMapStringsSep "\n" toCSSFile [
+            ./config/qutebrowser/github.scss
+            ./config/qutebrowser/monospace-textareas.scss
+            ./config/qutebrowser/quora.scss
+            ./config/qutebrowser/stackoverflow.scss
+            ./config/qutebrowser/xkcd.scss
+            ./config/qutebrowser/youtube.scss
+          ];
+        };
+      };
+    }
+
+    # Desktop (X11) theming
+    (mkIf config.services.xserver.enable {
+      user.packages = with pkgs; [
+        unstable.dracula-theme
+        paper-icon-theme # for rofi
+      ];
+      fonts.fonts = [ pkgs.jetbrains-mono ];
+
+      # Compositor
+      services.picom = {
+        fade = true;
+        fadeDelta = 1;
+        fadeSteps = [ 0.01 0.012 ];
+        shadow = true;
+        shadowOffsets = [ (-10) (-10) ];
+        shadowOpacity = 0.22;
+        # activeOpacity = "1.00";
+        # inactiveOpacity = "0.92";
+        settings = {
+          shadow-radius = 12;
+          # blur-background = true;
+          # blur-background-frame = true;
+          # blur-background-fixed = true;
+          blur-kern = "7x7box";
+          blur-strength = 320;
+        };
+      };
+
+      # Login screen theme
+      services.xserver.displayManager.lightdm.greeters.mini.extraConfig = ''
+        text-color = "#ff79c6"
+        password-background-color = "#1E2029"
+        window-color = "#181a23"
+        border-color = "#181a23"
+      '';
+
+      # Other dotfiles
+      home.configFile = mkMerge [
+        {
+          # Sourced from sessionCommands in modules/themes/default.nix
+          "xtheme/90-theme".source = ./config/Xresources;
+        }
+        (mkIf m.desktop.bspwm.enable {
+          "bspwm/rc.d/polybar".source = ./config/polybar/run.sh;
+          "bspwm/rc.d/theme".source = ./config/bspwmrc;
+        })
+        (mkIf m.desktop.apps.rofi.enable {
+          "rofi/theme" = { source = ./config/rofi; recursive = true; };
+        })
+        (mkIf (m.desktop.bspwm.enable || m.desktop.stumpwm.enable) {
+          "polybar" = { source = ./config/polybar; recursive = true; };
+          "dunst/dunstrc".source = ./config/dunstrc;
+        })
+        (mkIf m.desktop.media.graphics.vector.enable {
+          "inkscape/templates/default.svg".source = ./config/inkscape/default-template.svg;
+        })
+      ];
+    })
+  ]);
+}
diff --git a/modules/themes/default.nix b/modules/themes/default.nix
index 6d5861e8..26c687b6 100644
--- a/modules/themes/default.nix
+++ b/modules/themes/default.nix
@@ -2,14 +2,123 @@
 # intertwined with others, and are solely responsible for aesthetics. Disabling
 # a theme module should never leave a system non-functional.
 
-{ config, lib, ... }:
+{ options, config, lib, pkgs, ... }:
 
 with lib;
 with lib.my;
-let cfg = config.modules.themes;
+let cfg = config.modules.theme;
 in {
-  assertions = [{
-    assertion = countAttrs (_: x: x.enable) cfg < 2;
-    message = "Can't have more than one theme enabled at a time";
-  }];
+  options.modules.theme = with types; {
+    active = mkOption {
+      type = nullOr str;
+      default = null;
+      apply = v: let theme = builtins.getEnv "THEME"; in
+                 if theme != "" then theme else v;
+      description = ''
+        Name of the theme to enable. Can be overridden by the THEME environment
+        variable. Themes can also be hot-swapped with 'hey theme $THEME'.
+      '';
+    };
+
+    wallpaper = mkOpt (either path null) null;
+
+    loginWallpaper = mkOpt (either path null)
+      (if cfg.wallpaper != null
+       then toFilteredImage cfg.wallpaper "-gaussian-blur 0x2 -modulate 70 -level 5%"
+       else null);
+
+    gtk = {
+      theme = mkOpt str "";
+      iconTheme = mkOpt str "";
+      cursorTheme = mkOpt str "";
+    };
+
+    onReload = mkOpt (attrsOf lines) {};
+  };
+
+  config = mkIf (cfg.active != null) (mkMerge [
+    # Read xresources files in ~/.config/xtheme/* to allow modular
+    # configuration of Xresources.
+    (let xrdb = ''xrdb -merge "$XDG_CONFIG_HOME"/xtheme/*'';
+     in {
+       services.xserver.displayManager.sessionCommands = xrdb;
+       modules.theme.onReload.xtheme = xrdb;
+     })
+
+    {
+      home.configFile = {
+        # GTK
+        "gtk-3.0/settings.ini".text = ''
+          [Settings]
+          ${optionalString (cfg.gtk.theme != "")
+            ''gtk-theme-name="${cfg.gtk.theme}"''}
+          ${optionalString (cfg.gtk.iconTheme != "")
+            ''gtk-icon-theme-name="${cfg.gtk.iconTheme}"''}
+          ${optionalString (cfg.gtk.cursorTheme != "")
+            ''gtk-cursor-theme-name="${cfg.gtk.cursorTheme}"''}
+          gtk-fallback-icon-theme=gnome
+          gtk-application-prefer-dark-theme=true
+          gtk-xft-hinting=1
+          gtk-xft-hintstyle=hintfull
+          gtk-xft-rgba=none
+        '';
+        # GTK2 global theme (widget and icon theme)
+        "gtk-2.0/gtkrc".text = ''
+          ${optionalString (cfg.gtk.theme != "")
+            ''gtk-theme-name="${cfg.gtk.theme}"''}
+          ${optionalString (cfg.gtk.iconTheme != "")
+            ''gtk-icon-theme-name="${cfg.gtk.iconTheme}"''}
+          gtk-font-name="Sans 10"
+        '';
+        # QT4/5 global theme
+        "Trolltech.conf".text = ''
+          [Qt]
+          ${optionalString (cfg.gtk.theme != "")
+            ''style="${cfg.gtk.theme}"''}
+        '';
+      };
+    }
+
+    (mkIf (cfg.wallpaper != null)
+      (let wCfg = config.services.xserver.desktopManager.wallpaper;
+           command = ''
+             if [ -e "$XDG_DATA_HOME/wallpaper" ]; then
+               ${pkgs.feh}/bin/feh --bg-${wCfg.mode} \
+                 ${optionalString wCfg.combineScreens "--no-xinerama"} \
+                 --no-fehbg \
+                 $XDG_DATA_HOME/wallpaper
+             fi
+          '';
+       in {
+         # Set the wallpaper ourselves so we don't need .background-image and/or
+         # .fehbg polluting $HOME
+         services.xserver.displayManager.sessionCommands = command;
+         modules.theme.onReload.wallpaper = command;
+
+         home.dataFile = mkIf (cfg.wallpaper != null) {
+           "wallpaper".source = cfg.wallpaper;
+         };
+       }))
+
+    (mkIf (cfg.loginWallpaper != null) {
+      services.xserver.displayManager.lightdm.background = cfg.loginWallpaper;
+    })
+
+    (mkIf (cfg.onReload != {}) {
+      user.packages = [
+        (pkgs.writeScriptBin "reloadTheme" ''
+          #!${stdenv.shell}
+          echo "Reloading current theme: ${cfg.active}"
+          ${concatStrings "\n"
+            (mapAttrsToList (name: script: ''
+              echo "[${name}]"
+              ${script}
+            '') cfg.onReload)}
+        '')
+      ];
+      system.userActivationScripts.reloadTheme = ''
+        [ -z "$NORELOAD" ] && reloadTheme
+      '';
+    })
+  ]);
 }
diff --git a/modules/themes/fluorescence/README.org b/modules/themes/fluorescence/README.org
deleted file mode 100644
index 33ca9ea3..00000000
--- a/modules/themes/fluorescence/README.org
+++ /dev/null
@@ -1,14 +0,0 @@
-#+TITLE:  Fluorescence
-#+AUTHOR: Henrik Lissner
-#+DATE:   October 1, 2019
-
-A regal dracula-inspired theme.
-
-* Wallpaper
-![Fluorescence wallpaper](config/wallpaper.jpg)
-
-* Screenshots
-![My desktop, pretending to look busy, with gaps](/../screenshots/fluorescence/fakebusy.png?raw=true)
-![My desktop, unfettered by windows](/../screenshots/fluorescence/desktop.png?raw=true)
-![My app launcher, rofi](/../screenshots/fluorescence/rofi.png?raw=true)
-![The gapless experience](/../screenshots/fluorescence/tiling.png?raw=true)
diff --git a/modules/themes/fluorescence/default.nix b/modules/themes/fluorescence/default.nix
deleted file mode 100644
index 9d3fc46d..00000000
--- a/modules/themes/fluorescence/default.nix
+++ /dev/null
@@ -1,130 +0,0 @@
-# modules/themes/fluorescence/default.nix --- a regal dracula-inspired theme
-
-{ options, config, lib, pkgs, ... }:
-
-with lib;
-with lib.my;
-let m   = config.modules;
-    cfg = m.themes.fluorescence;
-in {
-  options.modules.themes.fluorescence = with types; {
-    enable = mkBoolOpt false;
-    wallpaper = mkOpt (either path null) ./config/wallpaper.png;
-    loginWallpaper = mkOpt (either path null)
-      (toFilteredImage cfg.wallpaper "-gaussian-blur 0x2 -modulate 70 -level 5%");
-  };
-
-  config = mkIf cfg.enable (mkMerge [
-    # Desktop-agnostic configuration
-    {
-      home.configFile = mkIf m.shell.tmux.enable {
-        "tmux/theme".source = ./config/tmux.conf;
-      };
-      modules.shell.zsh.rcFiles = [ ./config/zsh/prompt.zsh ];
-    }
-
-    # Desktop (X11) theming
-    (mkIf config.services.xserver.enable {
-      user.packages = with pkgs; [
-        unstable.dracula-theme
-        paper-icon-theme # for rofi
-      ];
-      fonts.fonts = [ pkgs.jetbrains-mono ];
-
-      # Compositor
-      services.picom = {
-        fade = true;
-        fadeDelta = 1;
-        fadeSteps = [ 0.01 0.012 ];
-        shadow = true;
-        shadowOffsets = [ (-10) (-10) ];
-        shadowOpacity = 0.22;
-        # activeOpacity = "1.00";
-        # inactiveOpacity = "0.92";
-        settings = {
-          shadow-radius = 12;
-          # blur-background = true;
-          # blur-background-frame = true;
-          # blur-background-fixed = true;
-          blur-kern = "7x7box";
-          blur-strength = 320;
-        };
-      };
-
-      services.xserver.displayManager.lightdm = mkMerge [
-        # Login screen theme
-        {
-          greeters.mini.extraConfig = ''
-            text-color = "#ff79c6"
-            password-background-color = "#1E2029"
-            window-color = "#181a23"
-            border-color = "#181a23"
-          '';
-        }
-
-        (mkIf (cfg.loginWallpaper != null) {
-          background = cfg.loginWallpaper;
-        })
-      ];
-      home.dataFile = mkIf (cfg.wallpaper != null) {
-        "wallpaper".source = cfg.wallpaper;
-      };
-
-      modules.desktop.browsers = {
-        firefox.userChrome = concatMapStringsSep "\n" readFile [
-          ./config/firefox/userChrome.css
-        ];
-        qutebrowser.userStyles = concatMapStringsSep "\n" toCSSFile [
-          ./config/qutebrowser/github.scss
-          ./config/qutebrowser/monospace-textareas.scss
-          ./config/qutebrowser/quora.scss
-          ./config/qutebrowser/stackoverflow.scss
-          ./config/qutebrowser/xkcd.scss
-          ./config/qutebrowser/youtube.scss
-        ];
-      };
-
-      home.configFile = mkMerge [
-        {
-          # This is sourced in the displayManager (see
-          # modules/desktop/default.nix) to modularize my Xresources config.
-          "xtheme/90-theme".source = ./config/Xresources;
-          # GTK
-          "gtk-3.0/settings.ini".text = ''
-            [Settings]
-            gtk-theme-name=Dracula
-            gtk-icon-theme-name=Paper
-            gtk-fallback-icon-theme=gnome
-            gtk-application-prefer-dark-theme=true
-            gtk-cursor-theme-name=Paper
-            gtk-xft-hinting=1
-            gtk-xft-hintstyle=hintfull
-            gtk-xft-rgba=none
-          '';
-          # GTK2 global theme (widget and icon theme)
-          "gtk-2.0/gtkrc".text = ''
-            gtk-theme-name="Dracula"
-            gtk-icon-theme-name="Paper-Mono-Dark"
-            gtk-font-name="Sans 10"
-          '';
-          # QT4/5 global theme
-          "Trolltech.conf".text = "[Qt]\nstyle=Dracula";
-        }
-        (mkIf m.desktop.bspwm.enable {
-          "bspwm/rc.d/polybar".source = ./config/polybar/run.sh;
-          "bspwm/rc.d/theme".source = ./config/bspwmrc;
-        })
-        (mkIf m.desktop.apps.rofi.enable {
-          "rofi/theme" = { source = ./config/rofi; recursive = true; };
-        })
-        (mkIf (m.desktop.bspwm.enable || m.desktop.stumpwm.enable) {
-          "polybar" = { source = ./config/polybar; recursive = true; };
-          "dunst/dunstrc".source = ./config/dunstrc;
-        })
-        (mkIf m.desktop.media.graphics.vector.enable {
-          "inkscape/templates/default.svg".source = ./config/inkscape/default-template.svg;
-        })
-      ];
-    })
-  ]);
-}