#calculator-container{width:300px;margin:0 auto;text-align:center;background-color:#ccc;padding:20px}#calculator{text-align:center}button{background-color:#ff6900;padding:10px 20px;border:none;box-shadow:none;color:#fff}#result{padding:10%;color:green;font-size:34px;font-weight:700}