css trên giao diện mobile

<link rel="alternate" href="http://ten_website" hreflang="vi-vn" />

<link rel="alternate" media="only screen and (max-width: 640px)" href="http://m.ten_website/">
<link rel="alternate" media="handheld" href="http://m.ten_website/" />

**** subdomain

**** deca.vn

**** css giao dien dien thoai