Update docs

README-zh.md

@@ -100,7 +100,7 @@ https://gitlab.com/hwdsl2/setup-ipsec-vpn/-/raw/master/vpnsetup.sh
 
 对于有外部防火墙的服务器（比如 [EC2](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-security-groups.html)/[GCE](https://cloud.google.com/vpc/docs/firewalls)），请为 VPN 打开 UDP 端口 500 和 4500。
 
-另外，你也可以使用预构建的 [Docker 镜像](https://github.com/hwdsl2/docker-ipsec-vpn-server/blob/master/README-zh.md)。高级用户可以在 [Raspberry Pi](https://www.raspberrypi.org) 上安装。[[1]](https://elasticbyte.net/posts/setting-up-a-native-cisco-ipsec-vpn-server-using-a-raspberry-pi/) [[2]](https://www.stewright.me/2018/07/create-a-raspberry-pi-vpn-server-using-l2tpipsec/)
+另外，你也可以使用预构建的 [Docker 镜像](https://github.com/hwdsl2/docker-ipsec-vpn-server/blob/master/README-zh.md)。高级用户可以在 [Raspberry Pi](https://www.raspberrypi.com) 上安装。[[1]](https://elasticbyte.net/posts/setting-up-a-native-cisco-ipsec-vpn-server-using-a-raspberry-pi/) [[2]](https://www.stewright.me/2018/07/create-a-raspberry-pi-vpn-server-using-l2tpipsec/)
 
 :warning: **不要** 在你的 PC 或者 Mac 上运行这些脚本！它们只能用在服务器上！
 
@@ -163,9 +163,9 @@ https://gitlab.com/hwdsl2/setup-ipsec-vpn/-/raw/master/vpnsetup.sh
 如果无法下载，打开 [vpnsetup.sh](vpnsetup.sh)，然后点击右边的 `Raw` 按钮。按快捷键 `Ctrl/Cmd+A` 全选，`Ctrl/Cmd+C` 复制，然后粘贴到你喜欢的编辑器。
 </details>
 
-#### 可选：在安装 VPN 时自定义 IKEv2 选项。
+## 自定义 IKEv2 选项
 
-在安装 VPN 时，你可以自定义 IKEv2 选项。这是可选的。
+在安装 VPN 时，高级用户可以自定义 IKEv2 选项。这是可选的。
 
 <details>
 <summary>

README.md

@@ -100,7 +100,7 @@ Quick deploy to:
 
 For servers with an external firewall (e.g. [EC2](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-security-groups.html)/[GCE](https://cloud.google.com/vpc/docs/firewalls)), open UDP ports 500 and 4500 for the VPN.
 
-A pre-built [Docker image](https://github.com/hwdsl2/docker-ipsec-vpn-server) is also available. Advanced users can install on a [Raspberry Pi](https://www.raspberrypi.org). [[1]](https://elasticbyte.net/posts/setting-up-a-native-cisco-ipsec-vpn-server-using-a-raspberry-pi/) [[2]](https://www.stewright.me/2018/07/create-a-raspberry-pi-vpn-server-using-l2tpipsec/)
+A pre-built [Docker image](https://github.com/hwdsl2/docker-ipsec-vpn-server) is also available. Advanced users can install on a [Raspberry Pi](https://www.raspberrypi.com). [[1]](https://elasticbyte.net/posts/setting-up-a-native-cisco-ipsec-vpn-server-using-a-raspberry-pi/) [[2]](https://www.stewright.me/2018/07/create-a-raspberry-pi-vpn-server-using-l2tpipsec/)
 
 :warning: **DO NOT** run these scripts on your PC or Mac! They should only be used on a server!
 
@@ -163,9 +163,9 @@ https://gitlab.com/hwdsl2/setup-ipsec-vpn/-/raw/master/vpnsetup.sh
 If you are unable to download, open [vpnsetup.sh](vpnsetup.sh), then click the `Raw` button on the right. Press `Ctrl/Cmd+A` to select all, `Ctrl/Cmd+C` to copy, then paste into your favorite editor.
 </details>
 
-#### Optional: Customize IKEv2 options during VPN setup.
+## Customize IKEv2 options
 
-When installing the VPN, you can optionally customize IKEv2 options.
+When installing the VPN, advanced users can optionally customize IKEv2 options.
 
 <details>
 <summary>