If you recently upgraded your WordPress installation to run through https using SSL certificate and your theme went “nuts” it’s simply because the safe protocol doesn’t “like” to load resources from non secure http addresses. And your database is full of it. One of simplest fixes is getting the
SSL Insecure Content Fixer plugin, activating it, enabling the fix in settings. This should go over your database which includes all posts, pages and image links and simply replace all links starting with http to https.
After you’re done you can just deactivate the plugin and remove it in order to keep your WordPress installation as clean as possible. If you’re curious on what exactly is causing the errors you can use site like https://www.whynopadlock.com or ordinarily open up your website in Chrome, press CTRL+SHIFT+C to get Chrome Developer Tools, then click on console. You’ll see a lot of messages saying “this content was loaded over insecure protocol” – this will give you rough idea on what is causing the lack of green padlock on your site!