diff --git a/neovim/default.nix b/neovim/default.nix
index c06ccb7..8422c2a 100644
--- a/neovim/default.nix
+++ b/neovim/default.nix
@@ -177,7 +177,17 @@
 
         require("local_firenvim")
 
-        require("CopilotChat").setup()
+        require("CopilotChat").setup({
+          highlight_headers = false,
+          separator = "---",
+          error_header = "> [!ERROR] Error",
+          window = {
+            layout = "float",
+            width = 0.8,
+            height = 0.8,
+          }
+        })
+
         require("diffview").setup({
           view = {
             merge_tool = {
diff --git a/neovim/keymaps.lua b/neovim/keymaps.lua
index 2179b03..5ece7b2 100644
--- a/neovim/keymaps.lua
+++ b/neovim/keymaps.lua
@@ -67,3 +67,6 @@ vim.cmd('nnoremap <expr> * v:hlsearch ? ":nohlsearch<cr>" : "*"')
 
 -- insert-map jj/jk to escape
 require("better_escape").setup()
+
+-- open Copilot Chat window
+nnoremap("<leader>cc", ":lua require('CopilotChat').open()<CR>")