SOURCE

<div class="login-box">
		<h2>Login</h2>
		<form>
			<div class="login-field">
				<input type="text" name="" required="">
				<label>Username</label>
			</div>
			<div class="login-field">
				<input type="password" name="" required="">
				<label>Password</label>
			</div>
			<button type="submit" name="">Submit</button>
		</form>
	</div>

<!-- <script src="https://code.jquery.com/jquery-3.4.1.min.js"></script> -->

body {
		margin: 0;
		padding: 0;
		font-family: sans-serif;
		background: url(https://10wallpaper.com/wallpaper/1280x960/1205/lift_me_up-HD_Space_Wallpapers_1280x960.jpg);
		background-size: cover;
	}
	
	.login-box {
		position: absolute;
		top: 50%;
		left: 50%;
		transform: translate(-50%,-50%);
		width: 400px;
		padding: 40px;
		background: rgba(0,0,0,.8);
		box-sizing: border-box;
		box-shadow: 0 15px 25px rgba(0,0,0,.5);
		border-radius: 10px;
	}
	
	.login-box h2 {
		margin: 0 0 30px;
		padding: 0;
		text-align: center;
		color: #fff;
	}
	
	.login-box .login-field {
		position: relative;
		
	}
	
	.login-box .login-field input {
		width: 100%;
		padding: 10px 0;
		font-size: 16px;
		color: #fff;
		margin-bottom: 30px;
		border: none;
		border-bottom: 1px solid #fff;
		outline: none;
		background: transparent;
	}
	
	.login-box .login-field label {
		position: absolute;
		top: 0;
		left: 0;
		letter-spacing: 1px;
		padding: 10px 0;
		font-size: 16px;
		color: #fff;
		pointer-events: none;
		transition: .5s;		
	}
	
	.login-box .login-field input:focus ~ label,
	.login-box .login-field input:valid ~ label {
		top: -23px;
		left: 0;
		color: aqua;
		font-size: 12px;
	}
	
	.login-box button {
		background: transparent;
		border: none;
		outline: none;
		color: #fff;
		background: #03a9f4;
		padding: 10px 20px;
		cursor: pointer;
		border-radius: 5px;
	}