body {
    background-image: url(pic/about.jpg);
    background-repeat:no-repeat ;
    background-position:center;
    background-size: cover;
    background-attachment: fixed;
}

p{
    text-align-all: center;
    font-size: xx-large;
    color: green;
}

.but{
	width:300px;
	min-height:40px;
	display:block;
	background-color:orange;
	border:1px;
	color:#fff;
	padding:9px 14px;
	font-size:15px;
	line-height:normal;
	border-radius:5px;
	margin:20px;
}