nextcloud-server/apps/files_sharing/css/authenticate.css

#body-login form label.infield {
	width: 190px;
	padding: 10px;
	left: 8px;
	top: 8px;
}

#password {
	width: 190px !important;
	padding: 10px;
	margin:	6px;
}

input[type="submit"]{
	width: 45px;
	height: 45px;
	margin:	6px;
	background-image: url('%webroot%/core/img/actions/confirm.svg');
	background-repeat: no-repeat;
	background-position: center;
}

#body-login input[type="submit"] {
	position: absolute;
	top: 0px;
}