.calculator-container{max-width:400px;margin:0 auto;text-align:center;padding:20px;background-color:#f2f2f2;border:1px solid #ccc;border-radius:5px}.calculator-container h1{text-align:center}.calculator-container select,input{width:100%;padding:10px;margin-bottom:10px}.calculator-container button{background-color:#007bff;color:#fff;padding:10px;margin-bottom:10px}#fee_result{font-size:20px}