How to set the CentOS-Base.repo properly to install lxde?

[luofeiyu]

I want to have lxde installed on my cnetos7 with the command:
yum install -y lxde

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.btte.net
* extras: mirrors.nwsuaf.edu.cn
* updates: mirror.neu.edu.cn
No package lxde available.
Error: Nothing to do

How to set the CentOS-Base.repo properly to install lxde?
Here is my repo file ,the default one,i have not modify it.

[base]
name=CentOS-$releasever - Base
mirrorlist=http://mirrorlist.centos.org/?release=$ ... fra=$infra
#baseurl=http://mirror.centos.org/centos/$releas ... $basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#released updates
[updates]
name=CentOS-$releasever - Updates
mirrorlist=http://mirrorlist.centos.org/?release=$ ... fra=$infra
#baseurl=http://mirror.centos.org/centos/$releas ... $basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
mirrorlist=http://mirrorlist.centos.org/?release=$ ... fra=$infra
#baseurl=http://mirror.centos.org/centos/$releas ... $basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
mirrorlist=http://mirrorlist.centos.org/?release=$ ... fra=$infra
#baseurl=http://mirror.centos.org/centos/$releas ... $basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

[TrevorH]

You will not find LXDE in the CentOS repos as we do not ship it. I don't see it in any of my third party (non-CentOS) yum repositories either - so not in EPEL or nux-dextop. There are other lightweight window managers around: xfce and MATE are both in EPEL and nux-dextop supplies some extra MATE packages as well.