<body class="background">
<div class="cor">
<label>User</label>
</div>
<div class="cor">
<input type="text" id="user">
</div>
<div class="cor">
<label>Password</label>
</div>
<div class="cor">
<input type="text" id="pass">
</div>
<div class="cor">
<button>Enter</button>
</div>
</body>
<style>
<--- This values i used in a Full HD monitor(1920 X 1080) --->
<--- Estes valores eu usei num monitor Full HD(1920 X 1080) --->
.background{
background-image: url (https://www.teahub.io/photos/full/97-976476_doom-wallpaper-hd.jpg);
background-size: cover;
background-repeat: no-repeat;
text-align:center;
padding:15%
}
.cor{
background: #b07517;
width: 25%;
margin-left: auto;
margin-right: auto;
}
</style>