add a vim-like command line under :

content/treehouse/cmd.tree

@@ -0,0 +1,20 @@
+%% title = "command line"
+
+% id = "01JEK4XKK26T6W603FTPQHQ7C8"
+- press `<kbd>:</kbd>`{=html} to open the command line.
+
+    % id = "01JEK4XKK27KXP01EK8K890SPK"
+    - type in your command, then press `<kbd>Enter</kbd>`{=html} to run it.
+    
+    - `<kbd>Esc</kbd>`{=html} closes the command line.
+
+    - `<kbd>Tab</kbd>`{=html} cycles through suggestions.
+
+    - you may also use the mouse to close the command line or pick a suggestion from the list.
+
+% id = "01JEK4XKK2EDTVCNZQRV9XDZXJ"
+- unknown commands do not do anything.
+known commands usually result in immediate feedback.
+
+% id = "01JEK4XKK2S4W0TPT4JY8AH143"
+- the command line is currently not accessible on mobile devices.

content/treehouse/dev/tools.tree

@@ -1,5 +1,5 @@
 %% title = "developer tools"
-styles = ["page/treehouse/dev/tools.css"]
+styles = ["dev.css"]
 scripts = ["treehouse/dev/picture-upload.js"]
 
 % id = "01JEHDJSJP282VCTRKYHNFM4N7"