How to make HTTPS domain pull in the CSS data?

Question

I'm having some issues in IE8 where when I go to https://www.myapp.com, I get a security warning that says:

Security Warning: "Do you want to view only the webpage content that was delivered securely?" 

It appears that my CSS files are getting blocked because when I choose "Yes", there's no styling.

I looked at my page source on my homepage as well as on the internal pages and this is what I found:

    <link href="/assets/application.css?body=1" media="all" rel="stylesheet" type="text/css" />
<link href="/assets/active_admin.css?body=1" media="all" rel="stylesheet" type="text/css" />
<link href="/assets/comments.css?body=1" media="all" rel="stylesheet" type="text/css" />
<link href="/assets/custom.css?body=1" media="all" rel="stylesheet" type="text/css" />
<link href="/assets/sessions.css?body=1" media="all" rel="stylesheet" type="text/css" />
<link href="/assets/static_pages.css?body=1" media="all" rel="stylesheet" type="text/css" />

How can I make it so that HTTPS renders in my CSS files without that security warning? I'm a beginner so even after looking in various files I wasn't sure where to find the data to change.

Also, I'm using the Bootstrap-sass ruby gem if anyone is familiar with that. In my CSS file, I have @import "bootstrap";

Answer 1

Use protocol-relative links of the following form for external resources. They will ensure that those resources gets served over https when required. (For example, if linking in an external script-library)

//domain.com/external/resource

Also use the same path-relative-absolute style, to request resources within your css as well.

.elem{ background: url(/path/to/something.png); }

Answer 2

Open your CSS files and look for any absolute url in there loading any image via HTTP. This happens when any element is loaded on an HTTP URL. Most probably your CSS files are including any background or any image from a complete url which is hardcoded as HTTP. Even the jquery source files if you have, have to be linked HTTPS