* { margin:0; padding:0; box-sizing:border-box; }
html, body { height:100%;  }
body { background-color:#e4e4e4; color:#000; }
.content {
    max-width:500px;
    margin:0 auto;
    height:100%;
    padding:10px; 
    background-color:#fff;
}

.content h1 { text-align:center; font-size:20px; padding:10px; color:#000; }
.content .image { margin:10px;  }
.content .image img { width:100%; }
.btn { 
    background-color: skyblue;
    padding: 15px;
    text-align: center;
    display: table;
    margin:10px auto;
}
.btn:hover { background-color:#215421; }
a  { text-decoration:none; color:#fff; font-weight:bold;}
footer { margin-top:20px; border-top:1px solid #eee; padding-top:10px; font-size:12px; text-align:center; }