*,*:before,*:after{box-sizing:border-box}body{margin:0;font-family:system-ui,sans-serif;background:#0f0f0f;color:#e8e8e8}header{display:flex;justify-content:space-between;align-items:center;padding:1rem 2rem;border-bottom:1px solid #2a2a2a}main{max-width:900px;margin:2rem auto;padding:0 2rem}button{padding:.5rem 1.25rem;background:#2563eb;color:#fff;border:none;border-radius:6px;cursor:pointer}button:hover{background:#1d4ed8}