# Changing syntax modes

Various functions of the editor are controlled by your currently selected syntax mode, including syntax highlighting, autocompletion, and hints.

For best results, make sure your syntax mode matches the type of document you are editing. For example: CSS mode for .css files, etc.

Generally, Coda manages this automatically for you, but there may be occasions when you have to manually change the syntax mode.

To change the syntax mode:

- Choose the appropriate syntax mode from the Text > Syntax Modes sub-menu, or
- Choose from the Syntax Modes sub-menu in the editor's action button

Coda may not be able to determine which syntax mode to use for an unfamiliar file extension. To assign a particular syntax mode to a particular file extension:

1. Choose Coda > Preferences...
2. Click Editor
3. Click the + button below the Custom Syntax Modes table
4. Enter the desired extension and choose which syntax mode it should use

Coda is compatible with syntax mode files used by SubEthaEdit. To use SubEthaEdit syntax mode files, place them in either of two locations:

- Home > Library > Application Support > Coda > Modes (only affects you)
- Library > Application Support > Coda > Modes (affects all users of the computer)