html, body { height:100%; }

body > .container,
body > .container-fluid {
    flex: 1 0 auto;          
    display: flex;
    flex-direction: column; 
}

body > .container > main,
body > .container-fluid > main {
    flex: 1 0 auto;
    overflow: auto;
}

main{
  flex:1 0 auto;      
  overflow:auto;    
}