First of all, download these two images and upload them to your theme directory.
Next, we will navigate to AdminCP > Templates & Style > Themes > Your theme > global.css and open it in the advanced editor.
Add this code:
Code:
#spinner {
background: #303030 !important;
-webkit-border-radius: 50%;
-moz-border-radius: 50%;
border-radius: 50%;
color: #ccc !important;
border: 1px solid #404040 !important;
-webkit-box-shadow: 0px 0px 10px 1px #000;
box-shadow: 0px 0px 10px 1px #000;
}
If the new spinner doesn't show up immediately, clear your cache.
If you're using cloudflare, go to CloudFlare settings and click "purge cache".