①hederの中に下記を記載する
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.6.4/css/all.css">
②bodyの中に下記を記載する
<div id="page_top"><a href="#"></a></div>
③CSSに下記を記載する
page_top{
width: 50px;
height: 50px;
position: fixed;
right: 0;
bottom: 0;
background: #3f98ef;
opacity: 0.6;
border-radius: 50%;
}
page_top a{
position: relative;
display: block;
width: 50px;
height: 50px;
text-decoration: none;
}
page_top a::before{
font-family: 'Font Awesome 5 Free';
font-weight: 900;
content: '\f102';
font-size: 25px;
color: #fff;
position: absolute;
width: 25px;
height: 25px;
top: -5px;
bottom: 0;
right: 0;
left: 0;
margin: auto;
text-align: center;
}