As follows:
<! DOCTYPE html>
<meta charset= "Utf-8" >
<meta http-equiv= "x-ua-compatible" content= "Ie=edge" >
<meta name= "viewport" content= "Width=device-width, initial-scale=1" >
<meta name= "description" content= "" >
<meta name= "Author" content= "" >
<link rel= "icon" href= ". /.. /favicon.ico ">
<title>signin Template for Bootstrap</title>
<!--Bootstrap Core CSS--
<link href= "Http://cdn.bootcss.com/bootstrap/3.3.2/css/bootstrap.min.css" rel= "stylesheet" >
<style>
. vertical-center {
Position:absolute;
top:40%;
left:50%;
Transform:translate (-50%,-50%);
}
</style>
<body>
<div class= "Container vertical-center" style= "border:1px solid blue;" >
<div class= "col-lg-4 col-lg-offset-4 col-sm-6 col-sm-offset-3 col-xs-8 col-xs-offset-2" id= "Logindev" style= "border : 1px solid red; " >
<form class= "Form" >
<label for= "Inputemail" class= "sr-only" >email address</label>
<input type= "Email" id= "Inputemail" class= "Form-control" placeholder= "email address" required= "autofocus=" ">
<label for= "Inputpassword" class= "Sr-only" >Password</label>
<input type= "Password" id= "Inputpassword" class= "Form-control" placeholder= "password" required= "" >
<div class= "checkbox" >
<label>
<input type= "checkbox" value= "Remember-me" > Remember Me
</label>
</div>
<button class= "btn btn-lg btn-primary Btn-block" type= "Submit" >sign in</button>
</form>
</div>
</div> <!--/container--
</body>
My Vertical Center