How to Create a Simple Website with HTML, CSS, and jQuery ( TypeB: Fixed Header & Footer )

style.css

@charset "utf-8";
@import url(https://fonts.googleapis.com/css?family=Open+Sans:400,700);
  
/*
============================
    Common
============================    
*/
body {
    margin: 0;
    font-family: 'Open Sans', sans-serif;
}

/*
============================
    Header
============================    
*/
#header {
    background-color: navy;
    height: 60px;
    width: 100%;
    position: fixed;
} 
ul#menu {
    width: 100%;
    padding: 0;
    margin: 0;
    list-style: none;
}
ul#menu li {
    float: left;
    padding: 20px 0 0 0;
    height: 60px;
    box-sizing: border-box;
}
li.site_name {
    width: 60%;
    text-align: left;
}
li.site_name a {
    color: white;
    text-decoration: none;
    padding-left: 30px;
}
li.link {
    width: 10%;
    text-align: center;
}
li.link a {
    color: white;
    text-decoration: none;
}
li.site_name a:hover, li.link a:hover {
    color: lightcyan;
}
  
/*
============================
    Contents
============================    
*/
  
#contents {
    width: 40%;
    margin: 0 auto;
    padding: 10px 0 130px 0;
}
h1 {
    padding-top: 100px;
}
.top {
    bottom: 50px;
    right: 50px;
    position: fixed;
    z-index: 100;
    color: navy;
}

/*
============================
    Footer
============================    
*/
#footer {
    background-color: navy;
    bottom: 0;
    width: 100%;
    height: 30px;
    position: fixed;
    box-sizing: border-box;
    text-align: center;
    color: white;
    font-size: 12px;
    padding-top: 6px;
}