Append custom class to wordpress headway theme
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I would like to hack headway theme by adding an option to pages to append custom "classes" for that particular page. It's similar to your regular page where you have an option to select page template. but instead of selecting page template user would just have to select the class he/she wanted to append on the page. that class will have a CSS overide.

Example:

**HTML**

    <body class=" red ...other headway css classes..." ">

**CSS**

    body.red #container { background: red }
    body.green #container { background: green }





1. I want to add a custom dropdown that list some classes option for theme to choose. example item on the dropdown. "red theme", "blue theme". This can also be done using Custom field but prefred to use dropdown so user won't get it wrong.


2. Append the class that was selected on the page to the <body> tag of that page. I tried using "body_class" on my functions.php But It totally erased all the classes causing my page to break appart. What I wanted to do is just append the custom class instead of erasing the entire classes of the body.

Please advice. thanks!