html, body {
  height: 100%;
  margin: 0;
}
.mask {
  	height: 100%;
  /* Equal to height of footer */
  /* But also accounting for potential margin-bottom of last child */
}
footer
{
   position:relative;
   left:0px;
   bottom:50px;
   height:50px;
   width:100%;
}
.footer_parent{
	position: relative;
	height:100%;
}

.the_point_of_this_page{
	min-height: 100vh;
	padding-bottom: 100px
}
.not_footer{
	display:none;
}
.min_height_50vh{
	min-height: 50vh;
}