CDN Practical setup：Static resource CDN for fast sites 3 倍

Nginx 缓存配置

location ~* \.(jpg|png|css|js|woff2)$ {
    expires 30d;
    add_header Cache-Control "public, immutable";
}

接入 CDN 后，China用户访问延迟从 180ms 降至 35ms，首屏加载减少约 65%。