style.css

*{
     margin: 0;
     padding: 0;
     font-family: 'Poppins' , sans-serif;
      bax-sizing : border-box;
 
 }
 .container{
     width: 100%;
     height: 100vh;
     display: flex;
     align-items: center;
 justify-content: center;
 background-color: #e3f9ff;
 }
 .calculator{
     background-color: #304452;
     padding: 20px;
     border-radius: 10px;
 
 }
 .calculator form input{
     border: 0;
     outline:0;
     width: 60px;
     height: 60px;
     border-radius: 10px;
     box-shadow: -8px -8px 15px rgba(255,255,255,0.1), 5px 5px 10px rgba(0,0,0,0.2);
     background: transparent;
     font-size: 20px;
     color: white;
     cursor: pointer;
     margin: 10px;
     
 }
 .display{
     display: flex;
     justify-content: flex-end;
     margin: 20px 0px;
 
 }
 form .display input{
     text-align: right;
     font-size: 45px;
     box-shadow: none;
     flex: 1;
 }
 form input.equal {
     width: 145px;}
 
     form input.op{
         color: #33ffd8;
     }
        h1 {text-align: center;
     
         color: red;
     }
     h1::first-letter{
         color: #85ff33;
     }