*{box-sizing:border-box}body{margin:0;font-family:system-ui,sans-serif;background:#f5f6f8;color:#222}
nav{display:flex;gap:16px;align-items:center;padding:12px 24px;background:#1f2937}
nav a{color:#fff;text-decoration:none}.spacer{flex:1}
.btn,button{background:#2563eb;color:#fff!important;border:0;padding:8px 16px;border-radius:6px;cursor:pointer;text-decoration:none;display:inline-block}
main{max-width:800px;margin:32px auto;padding:0 16px}
.card{max-width:380px;margin:40px auto;background:#fff;padding:24px;border-radius:10px;box-shadow:0 2px 8px #0002}
input[type=text]{width:100%;padding:10px;margin:12px 0;border:1px solid #bbb;border-radius:6px}
.error{color:#b91c1c}footer{text-align:center;padding:24px;color:#777}