style.css

*{
    margin: 0px; 
    padding: 0px;
    box-sizing: border-box;
    background-color: #ecf0f3;
    font-size:15px;
    /* border: none; */
}
.container{
   
   
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    
}
.calculator{
    padding: 25px;
    background-color: #ecf0f3 ;
    border-radius: 30px;
    box-shadow: inset 5px 5px 5px 12px #ffff,
                      5px 5px 5px 12px rgba(0,0,0,0.16);
    display: grid;
    grid-template-columns: repeat(4, 70px);
}

input{
    grid-column: span 4;
    height: 70px;
    background-color: #ecf0f3;
    border-radius: 30px;
    box-shadow: inset -5px -5px 12px #ffff,
                inset  5px  5px 12px rgba(0,0,0,0.16);
    font-size:50px;    
    text-align: end;  
    border: none;   
    color: rgb(70,70,70);
    /* margin: auto; */
    margin-top: 40px;
    margin-bottom: 30px;
    padding: 20px;
}
button{
    height:50px;
    width: 50px;
    margin:5px 5px ;
    border-radius: 50%;
    border: none;
    background-color: #ecf0f3;
    box-shadow: inset -5px -5px 12px #ffff,
    inset  5px  5px 12px rgba(0,0,0,0.16);

}
.equal{
    width: 115px;
    
    border-radius: 35%;
}