Css design problems

Sir, i want to include two frameworks in my applications.

one framework is useful for webpage layout designs and it contains

groundwork.css and groundwork.js file;

another framework is useful for window themes, create the modal and modaless window and

it contains easyui.css and easyui.js files

i include both frameworks in my application like.. .

<link href="css/groundwork.css" rel="stylesheet" type="text/css" />

<script src="js/groundwork.all.js" type="text/javascript"></script>

<link href="css/easyui.css" rel="stylesheet" type="text/css" />

<script src="js/easyui.js" type="text/javascript"></script>

My problem is

• i create an element like comboBox .. . this design is affected by the frameworks.
• How can i include mutiple css classes
• how can i avoid certain conflicts b\w the frameworks..

i thought .. . i doesn't know .. .how to ask the questions..

but my problem is .. . include multipe css files without conflicts likewise include multiple js files without conflicts.. .

sorry for bothering .. . pls explain to solve this issue.. .