[Solved] display login pop up

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your html and css tweaked to achieve your final lookup.

check below 

@import url(http://fonts.googleapis.com/css?family=Roboto);    
/****** LOGIN MODAL ******/
.loginmodal-container {
  max-width: 350px;
  width: 100% !important;
  background-color: #eceff6;
  margin: 0 auto;
  border-radius: 6px;
  box-shadow: 0px 2px 2px rgba(0, 0, 0, 0.3);
  overflow: hidden;
  font-family: roboto;
  border:8px solid;
  border-color:rgba(0,0,0,0.5);
}
#popupHeader
{
    background-color:#3c5899;padding:5px;
    margin-bottom:25px;
}
.loginmodal-container form{padding:35px;}
.loginmodal-container h1 {
  text-align: center;
  font-size: 1.2em;
  margin:0px;
  font-family: roboto;
  color:#fff;
}

.loginmodal-container input[type=submit] {
  width: 100%;
  display: block;
  margin-bottom: 10px;
  position: relative;
}

.loginmodal-container input[type=text], input[type=password] {
  height: 30px;
  font-size: 16px;
  width: 100%;
  -webkit-appearance: none;
  background: #fff;
  border: 1px solid #d9d9d9;
  border-top: 1px solid #c0c0c0;
  /* border-radius: 2px; */
  padding: 0 8px;
  box-sizing: border-box;
  -moz-box-sizing: border-box;
}

.loginmodal-container input[type=text]:hover, input[type=password]:hover {
  border: 1px solid #b9b9b9;
  border-top: 1px solid #a0a0a0;
  -moz-box-shadow: inset 0 1px 2px rgba(0,0,0,0.1);
  -webkit-box-shadow: inset 0 1px 2px rgba(0,0,0,0.1);
  box-shadow: inset 0 1px 2px rgba(0,0,0,0.1);
}

.loginmodal {
  text-align: center;
  font-size: 14px;
  font-family: 'Arial', sans-serif;
  font-weight: 700;
  height: 36px;
  padding: 0 8px;
/* border-radius: 3px; */
/* -webkit-user-select: none;
  user-select: none; */
}

.loginmodal-submit {
  /* border: 1px solid #3079ed; */
  border: 0px;
  color: #fff;
  text-shadow: 0 1px rgba(0,0,0,0.1); 
  background-color: #5e75a7;
  padding: 10px 0px;
  font-family: roboto;
  font-size: 14px;
  margin-top:20px;
  border-radius:4px;
}

.loginmodal-submit:hover {
  /* border: 1px solid #2f5bb7; */
  border: 0px;
  text-shadow: 0 1px rgba(0,0,0,0.3);
  background-color: #6a8acf;
}

.loginmodal-container a {
  text-decoration: none;
  color: #666;
  font-weight: 400;
  text-align: center;
  display: inline-block;
  opacity: 0.6;
  transition: opacity ease 0.5s;
} 

.login-help{
  font-size: 12px;
  margin-bottom:50px;
}
.login-help a{display:block;text-align:center;}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
<link href="https://fonts.googleapis.com/css?family=Roboto" rel="stylesheet">



<a href="#" data-toggle="modal" data-target="#login-modal">Login</a>

<div class="modal fade" id="login-modal" tabindex="-1" role="dialog">
    	  <div class="modal-dialog">
				<div class="loginmodal-container">
                    <div class="row" id="popupHeader">
                        <div class="col-xs-12 text">
                            <h1>Login to Your Account</h1>    
                        </div>
                    </div>
				  <form>
					<input type="text" name="user" placeholder="Username">
					<input type="password" name="pass" placeholder="Password">
					<input type="submit" name="login" class="login loginmodal-submit" value="Login">
				  </form>
					
				  <div class="login-help">
					<a href="#">Register</a><a href="#">Forgot Password</a>
				  </div>
				</div>
			</div>
		  </div>

solved display login pop up