:root{font-family:system-ui,sans-serif;color:#182633;background:#f3f6f8;line-height:1.5}
*{box-sizing:border-box}body{margin:0}main{max-width:760px;margin:6vh auto;padding:28px;background:white;border-radius:12px;border:1px solid #d9e1e8}
header{display:flex;justify-content:space-between;align-items:center;gap:16px}h1{font-size:1.6rem}h2{font-size:1.2rem}form{max-width:360px;margin:24px auto}label{display:block;margin:16px 0 5px}input,button{font:inherit;border:1px solid #9aa9b5;border-radius:6px;padding:10px}input{width:100%}button{cursor:pointer;background:#185477;color:white}form button{width:100%;margin-top:22px}button:disabled{opacity:.65;cursor:wait}a:focus-visible,input:focus-visible,button:focus-visible{outline:3px solid #e6a900;outline-offset:3px}[hidden]{display:none!important}#error{color:#9c2020;background:#fff2f0;padding:12px}#courses{display:flex;gap:12px;flex-wrap:wrap}.course{padding:18px 24px;border:1px solid #b9cbd8;border-radius:8px;color:#185477;text-decoration:none}.course[aria-disabled]{color:#63717b;background:#f6f7f8}@media(max-width:600px){main{margin:0;min-height:100vh;border:0;border-radius:0;padding:20px}}