*{box-sizing:border-box}body{margin:0;background:#f5f7fb;color:#17253a;font:17px/1.7 system-ui,-apple-system,sans-serif}header,main,footer{width:min(840px,100% - 40px);margin:auto}header{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:28px 0;border-bottom:1px solid #d6dfeb}.brand{font-size:22px;font-weight:750;text-decoration:none}nav{display:flex;gap:20px}a{color:#1559a6;text-underline-offset:3px}a:focus-visible{outline:3px solid #1559a6;outline-offset:5px}main{padding:35px 0 40px}h1{font-size:clamp(30px,6vw,44px);line-height:1.2;margin:0 0 20px}h2{font-size:23px;line-height:1.3;margin:32px 0 10px}p{margin:12px 0}.muted,footer{color:#536278}.note{background:#e7effb;border-left:4px solid #216ad0;padding:20px;border-radius:4px}.button{display:inline-block;background:#1559a6;color:white;padding:12px 22px;border-radius:10px;font-weight:650;text-decoration:none}footer{padding:24px 0 36px;border-top:1px solid #d6dfeb;font-size:14px}@media(max-width:420px){header{align-items:flex-start;flex-direction:column;gap:8px}}