html {  background-image:url(2.png);
background-attachment: fixed;
}

body {
width: 800px;
margin: 30px auto;
background: #CDEEF2;
border-radius: 5px;
text-align: center;
background: url(3.png) no-repeat center;
  -webkit-background-size: cover;
  background-size: cover;
  min-height: 100vh;
}

header {
background: #58E000;
color: #FFEFA5;
width: 775px;
height: 100px;
border:solid #1D8300;
padding: 10px;
text-align: center;
border-radius: 5px;
}

nav a {
color: #FFEFA5;
text-decoration: none;
padding: 5px 40px;
}

nav a:hover {
/*text-decoration: underline;*/
border-bottom: 2px solid;
}

main, footer {
padding: 20px;
}