style.css

body{
	margin:0;
	padding:0;
	background:url(images/bg.jpg);
	background-size: cover;
	font-family:sens-serif;
}

.loginbox{
	position: absolute;
	top: 50%;
    left: 50%;
	transform: translate(-50%,-50%);
	height:420px;
	width:350px;
	padding: 80px 40px;  
	box-sizing: border-box;
	background: rgba(255,255,255,.4);
}

h3{
	margin:0;
	padding:0 0 20px;
	color: blue;
	text-align: center;
}

.loginbox p{
	margin:0;
	padding:0;
	font-weight:bold;
	color:black;
	
}

.loginbox input{
	width:100%;
	margin-bottom: 20px; 
}


input{
	border: none;
	border-bottom:  1px solid black; 
	background: transparent;
	outline:none;
	height:40px; 
	color:black;
	font-size:16px;
	
}

::placeholder{
	color:rgba(0,0,0,.9);
}

.loginbox input[type="submit"]
{
	border:none;
	outline:none;
	height:40px;
	color:black;
	font-size:16px;
	background:green;
	cursor:pointer;
	border-radius:20px;
}

.loginbox input[type="submit"]:hover{
	background: lightgreen;
	color: blue;
}