Beginning in version 9.5 of the ACM, the system allows you to edit a site's current design package without having to download the design package. You can edit it within the ACM using a special design package editor.
From the System menu, go to the Site Design manager.
Click the Manage Templates button.
In the Download Templates section, select the Site whose templates you wish to edit.
The currently used design package - the one at the top of the list of packages - displays an icon to the right of its name. Click this Edit icon 
to display the Edit Template Package page.
Select files to edit in the Edit Template Package section.
Once you have completed all of your edits, you can click Save New to save the changes to a new version of the design package, or you can click Save All to overwrite the existing design package with your new edits. The safest method is to Save New. That way you can revert to the previous design package if you need to.