As they say, a picture is worth a thousand words. It looks like your css isn't loading. I use Firefox, and in Firefox, you can right click on a page and view source.
When you view the source, you should see a list near the top like this:
<link rel="stylesheet" type="text/css" href="/manager/assets/ext3/resources/css/ext-all-notheme-min.css" />
<link rel="stylesheet" type="text/css" href="/manager/templates/default/css/xtheme-modx.css" />
<link rel="stylesheet" type="text/css" href="/manager/templates/default/css/index.css" />
<link rel="stylesheet" type="text/css" href="/manager/templates/default/css/login.css" />
Since this is the login page, and login is the last css on the list, it would seem like a good idea to see if you can get to that link. I see that in the source being generated, there is no base url, so I assume that this is relative to the root of the site.
In Firefox, it has the href values highlighted, and when I click on them, I can see the source. Check to see if you have permissions to see those files and that the files are in the expected location.
Hope this helps.