*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;color:#1a1a1a;background:#f8f9fa;line-height:1.6}.app{max-width:720px;margin:0 auto;padding:2rem 1rem}.nav{display:flex;gap:1.5rem;padding-bottom:1.5rem;margin-bottom:2rem;border-bottom:2px solid #e2e8f0}.nav a{text-decoration:none;color:#64748b;font-weight:500;padding:.25rem 0;border-bottom:2px solid transparent;transition:color .2s,border-color .2s}.nav a:hover{color:#1a1a1a}.nav a.active{color:#2563eb;border-bottom-color:#2563eb}.main{min-height:60vh}h1{font-size:1.75rem;margin-bottom:1rem}p{margin-bottom:.75rem;color:#475569}.form-group{margin-bottom:1rem}.form-group label{display:block;margin-bottom:.375rem;font-weight:500}.form-group input{width:100%;max-width:400px;padding:.625rem .75rem;border:1px solid #cbd5e1;border-radius:6px;font-size:1rem;transition:border-color .2s}.form-group input:focus{outline:none;border-color:#2563eb;box-shadow:0 0 0 3px #2563eb1a}button{padding:.625rem 1.5rem;background:#2563eb;color:#fff;border:none;border-radius:6px;font-size:1rem;font-weight:500;cursor:pointer;transition:background .2s}button:hover{background:#1d4ed8}button:disabled{background:#94a3b8;cursor:not-allowed}.message{margin-top:1rem;padding:.75rem 1rem;border-radius:6px;font-size:.9rem}.message.success{background:#f0fdf4;color:#166534;border:1px solid #bbf7d0}.message.error{background:#fef2f2;color:#991b1b;border:1px solid #fecaca}.back-link{display:inline-block;margin-top:1rem;color:#2563eb;text-decoration:none}.back-link:hover{text-decoration:underline}@media(max-width:480px){.app{padding:1rem}.nav{gap:1rem;font-size:.9rem}h1{font-size:1.4rem}}