You can set preferences that control the format of your CSS code whenever you create or edit a CSS rule using the Dreamweaver interface. For example, you can set preferences that will place all CSS properties on separate lines, place a blank line between CSS rules, and so on.
When you set CSS code formatting preferences, the preferences you select are automatically applied to all new CSS rules that you create. You can, however, also apply these preferences manually to individual documents. This might be useful if you have an older HTML or CSS document that needs formatting.