Split CSS
Use a group of CSS elements instead of only one, and only call CSS that is useful for the situation. Doing so minimizes the size of the page when it is first loaded, thus saving bandwidth and reducing CPU load.
Use a CDN
Some files such as the JavaScript libraries, CSS style sheets and images consume lots of network resources because there are lots of them and they are usually small. CDNs (Content Delivery Network) are thus recommended as they bring the files physically closer to users, saving large amounts of bandwidth and improving response time.