.calculator{max-width:600px;margin:0 auto;background:#fff;padding:20px;border-radius:8px;box-shadow:0 0 10px rgba(0,0,0,.1)}h1{text-align:center;color:#333}.form-group{margin-bottom:15px}label{display:block;margin-bottom:5px;font-weight:700}select,input[type=checkbox]{width:100%;padding:8px;margin-bottom:10px;border:1px solid #ddd;border-radius:4px}button{background:#4caf50;color:#fff;border:none;padding:10px 15px;border-radius:4px;cursor:pointer;width:100%;font-size:16px}button:hover{background:#45a049}.result{margin-top:20px;padding:10px;background:#e9f7ef;border-radius:4px;text-align:center}#totalCost{color:#2e7d32;font-weight:700}