html, body {
  height: 100% ;
  margin: 0 ;
  padding: 0 ;
}
.wrapper {
  display: table ;
  width: 100% ;
  height: 100% ;
}
.header, .content, .footer {
  display: table-row ;
}
.header, .footer {
  height: 0 ;
}
.inner {
  height: 100% ;
  overflow: auto ;
}