diff --git a/modules/home/tmux/default.nix b/modules/home/tmux/default.nix
index 08b9202..01d48b0 100644
--- a/modules/home/tmux/default.nix
+++ b/modules/home/tmux/default.nix
@@ -6,13 +6,16 @@ let
     (config.my.home.wm.windowManager != null)
   ];
 
-  mkTerminalFlags = opt: flag:
+  mkTerminalFlags = tmuxVar: opt: flag:
     let
-      mkFlag = term: ''set -as terminal-features ",${term}:${flag}"'';
+      mkFlag = term: ''set -as ${tmuxVar} ",${term}:${flag}"'';
       enabledTerminals = lib.filterAttrs (_: v: v.${opt}) cfg.terminalFeatures;
       terminals = lib.attrNames enabledTerminals;
     in
     lib.concatMapStringsSep "\n" mkFlag terminals;
+
+  mkTerminalFeatures = mkTerminalFlags "terminal-features";
+  mkTerminalOverrides = mkTerminalFlags "terminal-overrides";
 in
 {
   options.my.home.tmux = with lib; {
@@ -28,6 +31,8 @@ in
           hyperlinks = my.mkDisableOption "hyperlinks through OSC8";
 
           trueColor = my.mkDisableOption "24-bit (RGB) color support";
+
+          underscoreStyle = my.mkDisableOption "underscore style/color support";
         };
       });
 
@@ -54,6 +59,20 @@ in
     terminal = "tmux-256color"; # I want accurate termcap info
     aggressiveResize = true; # Automatic resize when switching client size
 
+    # FIXME
+    # * Sixel support
+    # * OSC 133 prompt integration
+    # FIXME: when sensible-on-top is disabled: check if any of those are unset
+    # * tmux bind-key $prefix_without_ctrl last-window
+    # *
+    # * tmux bind-key C-b send-prefix: included
+    # * aggressive resize? done
+    # * tmux bind-key C-p previous-window: done
+    # * tmux bind-key C-n next-window: done
+    # * C-r to refresh my config: done
+    # * tmux set-option -g focus-events on: done
+
+    # FIXME: make PRs for `bind-key` description
     plugins = with pkgs.tmuxPlugins; builtins.filter (attr: attr != { }) [
       # Open high-lighted files in copy mode
       open
@@ -123,9 +142,14 @@ in
       }
 
       # Force OSC8 hyperlinks for each relevant $TERM
-      ${mkTerminalFlags "hyperlinks" "hyperlinks"}
+      ${mkTerminalFeatures "hyperlinks" "hyperlinks"}
       # Force 24-bit color for each relevant $TERM
-      ${mkTerminalFlags "trueColor" "RGB"}
+      ${mkTerminalFeatures "trueColor" "RGB"}
+      # Force underscore style/color for each relevant $TERM
+      ${mkTerminalFeatures "underscoreStyle" "usstyle"}
+      # FIXME: see https://github.com/folke/tokyonight.nvim#fix-undercurls-in-tmux for additional overrides
+      ${mkTerminalOverrides "underscoreStyle" "Smulx=\\E[4::%p1%dm"}
+      ${mkTerminalOverrides "underscoreStyle" "Setulc=\\E[58::2::::%p1%{65536}%/%d::%p1%{256}%/%{255}%&%d::%p1%{255}%&%d%;m"}
     '';
   };
 }