Dynamic CRM Modify existing css of a form

Hello all,

I want to modify css of account form on page load and used following code:

function LoadCSS() {
var serverUrl = Xrm.Page.context.getClientUrl();
var path=serverUrl +"/WebResources/new_AccountCss.css";
var head = document.getElementsByTagName('head')[0];
var link = document.createElement('link');
link.rel = 'stylesheet';
link.type = 'text/css';
link.href = path;
//link.media = 'all';
head.appendChild(link);
}

and created CSS file :

new_AccountCss.css

and call LoadCSS method on load but not working.

Anyone have  idea.

thanks

akram