server {
    listen       80;
    server_name  _;

    root   /usr/share/nginx/html;
    index  index.html;

    # 字符集 + gzip
    charset utf-8;
    gzip on;
    gzip_types text/css application/javascript text/javascript application/json
               image/svg+xml application/xml text/xml application/xml+rss;

    # 安全 headers
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;

    # SPA 回退（虽然当前没路由，但留个兜底）
    location / {
        try_files $uri $uri/ $uri.html /index.html;
    }

    # 静态资源缓存（图片 / css / js）
    location ~* \.(css|js|jpg|jpeg|png|gif|svg|woff|woff2|ttf|eot)$ {
        expires 30d;
        add_header Cache-Control "public, max-age=2592000";
    }

    # 错误页 fallback
    error_page 404 /index.html;
}