The font for HipChat 4 on Windows doesn't looks good because the default font configured for the HipChat client. User cannot change font settings in the client application.

Want to change font style and size in application setting.

Workaround (Windows 8/10):

1. Open your editor as admin
2. Open Program Files (x86)\Atlassian\HipChat4\localweb\hipchat-client.css
3. Replace font-family value with your preferred font like below.

 body,
#page,
#hipchat {
  font-family: Meiryo;
  height: 100%;
  width: 100%;
  min-width: 750px;
  transition: 0.5s -webkit-filter linear, 0.5s filter linear;
}