CDN 公共库是指将常用的 JavaScript、CSS 等前端资源文件托管在全球分布的服务器上，方便开发者直接引用，从而提高网站加载速度、降低服务器负载。
hexo-theme-next cdn 格式
custom_cdn_url:
国际
cdnjs.com
custom_cdn_url: https://cdnjs.cloudflare.com/ajax/libs/${cdnjs_name}/${version}/${cdnjs_file}
unpkg.com
custom_cdn_url: https://unpkg.com/${npm_name}@${version}/${npm_file}
jsdelivr.com
custom_cdn_url: https://cdn.jsdelivr.net/npm/${npm_name}@${version}/${minified}
国内
bootcdn.cn
custom_cdn_url: https://cdn.bootcdn.net/ajax/libs/${cdnjs_name}/${version}/${cdnjs_file}
staticfile.net
custom_cdn_url: https://cdn.staticfile.net/${cdnjs_name}/${version}/${cdnjs_file}
zstatic.net
custom_cdn_url: https://s4.zstatic.net/ajax/libs/${cdnjs_name}/${version}/${cdnjs_file}
webcache.cn
custom_cdn_url: https://cdnjs.webstatic.cn/ajax/libs/${cdnjs_name}/${version}/${cdnjs_file}
custom_cdn_url: https://npm.webcache.cn/${npm_name}@${version}/${npm_file}
7ed.net
custom_cdn_url: https://use.sevencdn.com/ajax/libs/${cdnjs_name}/${version}/${cdnjs_file}