:root{--primary-color: #1677ff;--bg-color: #f5f5f5;--paper-color: #ffffff}body{font-family:Inter,system-ui,Avenir,Helvetica,Arial,sans-serif;line-height:1.5;font-weight:400;background-color:var(--bg-color);color:#333}.container{max-width:800px;margin:0 auto;padding:2rem;text-align:center}h1{font-size:2rem;margin-bottom:2rem}button{border-radius:8px;border:1px solid transparent;padding:.6em 1.2em;font-size:1em;font-weight:500;font-family:inherit;background-color:#1a1a1a;color:#fff;cursor:pointer;transition:border-color .25s;margin:0 5px}button:hover{border-color:#646cff;background-color:#333}button.secondary{background-color:#e0e0e0;color:#333}button.danger{background-color:#ff4d4f;color:#fff}button:disabled{opacity:.5;cursor:not-allowed}