style.css

body {
    font-family: Arial, sans-serif;
    background-color: #ffffff; 
  }
  .calculator {
    width:280px;
    height: 300px;
    margin: 100px ; 
    background-color: #13223D; 
    padding: 20px;
    font-size: 1em;
    font-family: Impact, Haettenschweiler, 'Arial Narrow Bold', sans-serif;
    border-radius: 20px;
    box-shadow: 0px 10px 20px #000;
   
  }
  .display {
    width:90%;
    height: 30px;
    background: #edebeb;
    color: #057E18;
    text-align: right;
    padding: 10px;
    box-sizing: border-box;
    border: none;
    border-radius: 5px;
    margin-bottom: 20px;
  }


  .key {
    width: 45px;
    height: 45px;
    background: #f3f1f1;
    display: inline-block;
    
    margin: 10px;
    text-align: center;
    line-height: 50px;
    border-radius: 50%; 
    cursor: pointer;
    color: #ED7A30;
    
   
  }
  .key:active {
    background: #343AEE;
    box-shadow: 0 2px #666;
    transform: translateY(2px);
  }