*{box-sizing:border-box}
body{margin:0;font-family:Arial,sans-serif;background:#eef2f7;color:#243244}
main{max-width:720px;margin:55px auto;background:#fff;padding:38px;border-top:7px solid #2563eb;box-shadow:0 12px 28px #0002}
h1{text-align:center;margin:0 0 25px;font-size:28px}
ol{margin:0;padding-left:28px}
li{margin:12px 0;padding:10px;background:#f8fafc;border-left:4px solid #60a5fa}
li a{color:#1d4ed8;text-decoration:none}
li a:hover{text-decoration:underline}
nav{margin-top:28px;padding-top:18px;border-top:1px solid #d1d5db;text-align:center}
nav a{color:#1d4ed8}