Custom CSS for each page
Design and Skin Customization
No, that's a different system. There are many different systems in jamroom. Which you use depends on your preferences. If you're a web developer/programmer who is comfortable with running a development environment then you'll use the skins system and modules system and upload stuff you create via SFTP to the site.
There are many ways to interact with jamroom but this way will give you the most freedom and most possibilities to over-ride.
If you are not comfortable with web development technologies such as CSS, HTML, PHP, jQuery ( javascript ), then you are limited to using the things that have already been created.
The pages module is one of those things. ADMIN -> PAGE CREATOR stores its contents in the database not the file system.
Site builder is another system again. It also stores its contents in the database not in the file system.
--edit--
If its just a small amount of CSS that you're interested in adding to tweak existing styles, probably the place you're after is
ACP -> SKINS -> (currently active skin) -> STYLE -> CUSTOM EDITOR
You can put CSS into there.
updated by @michael: 09/13/20 04:47:16AM