body{
margin:0;
padding:0;
font-family: 'Inter';
}

h1, h2, h3, h4, h5{
text-align:center;
border-bottom:1px solid silver;
padding:10px 0;
}

.body-ctr{
background-color:#ddd;
padding:50px 0;
box-sizing:border-box;
}

.ctr{
max-width:960px;
padding:40px;
box-sizing:border-box;
margin:0 auto;
background-color:#fff;
font-size:12px;
color:#333;
box-shadow:0 0 4px #000;
}

pre{
border:1px solid silver;
background-color:#ddd;
padding:10px;
overflow-x: auto;
}

p{
margin-top:40px;
}

.demo-list-33 > ul{
margin:0;
padding:10px 0;
width:33.3333%;
float:left;
box-sizing: border-box;
}

.demo-list-33 > ul > li{
list-style: none;
text-align:center;
padding:5px;
border: 1px solid silver;
margin-bottom: -1px;
margin-right: -1px;
}

.demo-list-33:before, .demo-list-33:after{
content:' ';
clear:both;
display:block;
}

a{text-decoration:none;}
a:hover{text-decoration:underline;}