body{background-color:#f8f9fa;font-family:'Segoe UI',Tahoma,Geneva,Verdana,sans-serif}header{background:#212529;color:#fff;padding:2rem 1rem;text-align:center}main{padding:2rem 1rem}.calculator-card{border-radius:1rem;box-shadow:0 .5rem 1rem rgba(0,0,0,.1);padding:2rem;background:#fff}.result-box{font-size:1.5rem;font-weight:700;color:#0d6efd}footer{background:#212529;color:#fff;padding:2rem 1rem;text-align:center;margin-top:2rem}.ads-placeholder{background:#e9ecef;border:1px dashed #6c757d;text-align:center;padding:1rem;margin-bottom:1rem;color:#6c757d}