:root{--primary: #0f172a;--primary-hover: #334155;--bg: #f8fafc;--surface: #ffffff;--border: #e2e8f0;--text: #334155}body{font-family:system-ui,-apple-system,sans-serif;background-color:var(--bg);color:var(--text);display:flex;justify-content:center;align-items:center;min-height:100vh;margin:0}.container{width:100%;max-width:480px;padding:1rem}.header{text-align:center;margin-bottom:2rem}.card{background:var(--surface);padding:2rem;border-radius:12px;box-shadow:0 4px 6px -1px #0000001a;border:1px solid var(--border)}.hidden{display:none}.input-group{margin-bottom:1rem}label{display:block;font-size:.875rem;font-weight:500;margin-bottom:.5rem}input{width:100%;padding:.75rem;border:1px solid var(--border);border-radius:6px;box-sizing:border-box}.btn-primary{width:100%;background:var(--primary);color:#fff;padding:.875rem;border:none;border-radius:6px;font-weight:600;cursor:pointer;margin-top:1rem}.btn-primary:hover{background:var(--primary-hover)}.btn-secondary{background:transparent;color:var(--text);border:none;cursor:pointer;margin-top:10px;width:100%;text-decoration:underline}.plan-summary{display:flex;justify-content:space-between;background:#f1f5f9;padding:1rem;border-radius:6px;margin-bottom:1.5rem;font-weight:600}#message-box{margin-top:1rem;padding:1rem;border-radius:6px;text-align:center}.success{background:#dcfce7;color:#166534}.error{background:#fee2e2;color:#991b1b}